- Engine:
- G3520B (S/N: GLF1-UP)
- Petroleum Engine:
- G3520B PETROLEUM (S/N: TPC1-UP)
Introduction
Note: Do not perform any procedure in this Special Instruction until you read this information and you understand this information.
This Special Instruction provides the following information for G3520B Industrial Engines:
- Requirements for the electrical system
- Proper welding practices
- Grounding procedures
- Required service tools
- Electrical components and electronic components
- Wiring connections and the corresponding functions that are available to the customer
- Initial start-up procedures
- Governor adjustment procedures
ReferenceInformation from the following sources will be needed for this Special Instruction:
- Complete analysis of the fuel
- Data from a complete fuel analysis that is entered into Caterpillar Software, LEKQ6378, "Methane Number Program"
- The engine performance data sheet from the engine Technical Marketing Information (TMI) or Gas Engine Rating Pro (GERP)
- Engine Operation and Maintenance Manual, SEBU7201
- Systems Operation, Testing and Adjusting, KENR5412
- Troubleshooting Manual, KENR5413
- Schematic, KENR5929
Requirements for the Electrical System
All of the wiring must conform to all of the codes that are applicable to the site. When you route the wiring, avoid acute bends and sharp edges. To protect the wiring harnesses, route the harnesses through metal conduit. A liquid tight conduit is recommended. Use proper support and alignment in order to avoid strain on the conduit.
Electrical power must be supplied to the junction box that serves as the main distribution panel for the engine control system. The engine control system requires a clean 24 VDC power supply capable of supplying 30 A of continuous power.
The maximum allowable AC ripple voltage is 150 mV AC peak to peak. For the wiring, the maximum allowable voltage drop is 1 VDC from the power supply to an Electronic Control Module (ECM) or to an actuator.
Grounding Practices
Proper grounding is necessary for optimum engine performance and for reliability. Improper grounding will result in electrical current paths that are uncontrolled and unreliable.
Uncontrolled electrical circuit paths can result in damage to main bearings, to crankshaft bearing journal surfaces, and to aluminum components. Uncontrolled electrical circuit paths can also cause electrical activity that may degrade the engine electronics and communications.
- Connect all metal cases that contain electrical components or electronic components to the cylinder block with an electrical ground strap.
- Do not connect the negative terminal from the electrical power supply directly to the cylinder block. Connect the negative terminal from the electrical power supply to the negative terminal "−" on the power distribution box.
- Ground the cylinder block with a ground strap that is furnished by the customer. Connect this ground strap to the ground plane.
- Use a separate ground strap to ground the battery negative terminal for the control system to the ground plane.
- Rubber couplings may connect the steel piping of the cooling system to the radiator. The couplings cause the piping and the radiator to be electrically isolated. Ensure that the piping and the radiator are continuously grounded to the cylinder block. Use ground straps that bypass the rubber couplings.
- Ensure that all grounds are secure and free of corrosion.
Proper Welding Procedures
Proper welding procedures are necessary in order to avoid damage to electronic controls. Perform welding on the engine according to the following procedure.
- Set the engine control to the "STOP" mode.
- Turn OFF the fuel supply to the engine.
- Disconnect the negative terminal from the battery.
- Disconnect the engine electronic components from the wiring harnesses: ECM, throttle actuator, actuator for the turbocharger compressor bypass, fuel metering valve and sensors.
- Protect the wiring harnesses from welding debris and/or from welding spatter.
- Connect the welder ground cable directly to the engine component that will be welded. Place the clamp close to the weld to reduce the possibility of welding current damage to the engine bearings, electrical, and engine components.
| NOTICE |
|---|
Do NOT use electrical components (ECM or sensors) or electronic component grounding points for grounding the welder. |
- Use standard welding procedures in order to weld the materials together.
Service Tools
The Caterpillar Electronic Technician (ET) is designed to run on a personal computer.
Cat ET can display the following information:
- Parameters
- Diagnostic codes
- Event codes
- Engine configuration
- Status of the monitoring system
Cat ET can perform the following functions:
- Perform diagnostic tests.
- Calibrate sensors.
- Download flash files.
- Set parameters.
| Service Tools | ||
|---|---|---|
| Pt. No. | Description | Functions |
| N/A | Personal Computer (PC) | The PC is required for the use of Cat ET. |
| JERD2124 | Software | Single user license for Cat ET Use the most recent version of this software. |
| JERD2129 | Software | Data subscription for all engines |
| 171-4400 (1) | Communication Adapter Gp | This group provides the communication between the PC and the engine. |
| 275-5120 (2) | Communication Adapter Gp | This group provides the communication between the PC and the engine. |
| 7X-1414 | Data Link Cable As | This cable connects the communication adapter to the service tool connector on the engine. |
| 237-7547 | Adapter Cable As | This cable connects to the USB port on computers that are not equipped with a serial port. |
| 8T-8726 | Adapter Cable As | This cable is for use between the jacks and the plugs of the sensors. |
| 151-6320 | Wire Removal Tool (Red) 14 Ga to 18 GA |
This tool is used for the removal of pins and sockets from Deutsch connectors and AMP connectors. |
| 121-9588 | Wire Removal Tool (Blue) 16 GA |
|
| 1U-5805 | Wire Removal Tool (Green) 14 GA |
|
| 1U-5804 | Crimp Tool | This tool is used for work with CE electrical connectors. |
| 146-4080 | Digital Multimeter | The multimeter is used for the testing and for the adjusting of electronic circuits. |
| 7X-1710 | Multimeter Probes | The probes are used with the multimeter to measure voltage in wiring harnesses without disconnecting the harnesses. |
| 156-1060 or 156-1070 | Emission Analyzer Tool | This tool is used to measure the level of emissions in the engine exhaust. The 156-1060 measures the levels of four different compounds. The 156-1070 measures the levels of six different compounds. Either tool may be used. |
| ( 1 ) | This item includes the 171-4401 Communication Adapter As . |
| ( 2 ) | This item includes the 275-5121 Communication Adapter As . The 7X-1700 Communication Adapter Gp may also be used. |
Note: For more information regarding the use of Cat ET and the PC requirements, refer to the documentation that accompanies your Cat ET software.
Connecting the Caterpillar Electronic Technician (ET)
The engine battery supplies the communication adapter with 24 VDC. Use the following procedure to connect Cat ET to the engine control system.
- Set the engine control to the OFF/RESET mode.
 | |
| Illustration 1 | g01221508 |
(1) PC (2) 237-7547 Adapter Cable As (3) 196-0055 Serial Cable (4) 171-4401 Communication Adapter II (5) 207-6845 Adapter Cable (6) 7X-1414 Data Link Cable | |
Note: Items (3), (4), and (5) are part of the 171-4400 Communication Adapter Gp . The 275-5120 Communication Adapter Gp will have similar items for the connection.
- Connect communications adapter (4) to a communications port on the PC by using one of the following methods:
- Connect cables (3) and (2) between the "PC CABLE" end of communication adapter (4) and the USB port of PC (1) .
- Connect cable (3) between the "PC CABLE" end of communication adapter (4) and the RS232 serial port of PC (1) .
- Connect cable (5) between communication adapter (4) and the service tool connector on the terminal box or control panel.
- Set the engine control to the STOP mode. The engine should be OFF.
If Cat ET and the communication adapter do not communicate with the ECM, refer to Troubleshooting, "Electronic Service Tool Does Not Communicate".
If Cat ET displays "Duplicate Type on data link. Unable to Service", check the harness code for the slave ECM.
The harness inside the terminal box for the slave ECM has a jumper wire (harness code) that connects terminals J3-29 and J3-60. The ECM that is connected to the harness reads the harness code. Now the ECM can operate as the slave ECM. The jumper wire must be connected in order for Cat ET to communicate with the modules. The jumper wire must be connected in order for the engine to crank. The jumper wire must remain connected in order for the engine to run.
Check the continuity between terminals J3-29 and J3-60. Verify that the jumper wire is in good condition. Make repairs, as needed.
Terminal Box
Note: The terminal box is designed to remain mounted on the engine. The mounting hardware includes isolators. Do not move the terminal box to a remote location. Moving the terminal box could result in wiring problems and in reduction of the service life of the components inside the terminal box.
 | |
| Illustration 2 | g01096220 |
Terminal box | |
The ECM is inside the terminal box. This terminal box provides the point of termination for all of the wiring that is related to the engine sensors and for the ignition system. The components in the terminal box's are identified in Illustrations 3 and 4.
 | |
| Illustration 3 | g01097717 |
The connectors on the terminal box connect the Electronic Control Module (ECM) to various engine controls, sensors, actuators. (1) Emergency stop button (2) Connector J6/P6 for the harness to the detonation sensors on the left side of the engine (3) J9 service tool connector for the Caterpillar Electronic Technician (ET) (4) Connectors J8/P8 for the harness from the engine (5) Connectors J7/P7 for the harness from the engine (6) Ignition harness for the cylinders on the left side of the engine (7) Connectors J10/P10 for the harness to the engine control panel | |
 | |
| Illustration 4 | g01097723 |
Components inside the terminal box for the master ECM (8) Master ECM (9) Ground strap (10) J2/P2 connectors (11) J1/P1 connectors (12) J5/P5 connector for the wiring to the customer connections (13) J13/P13 connector for the termination resistor for the CAN data link (14) P50 connector for calibration of the speed/timing sensor (15) Relay for activation of the throttle actuator (16) Relay for activation of the compressor bypass valve actuator | |
 | |
| Illustration 5 | g01947783 |
Connectors at the terminal box for the slave ECM (right side engine view) (17) (J3/P3) ECM connectors for the slave ECM (18) Ground strap (19) (J4/P4) ECM connectors for the slave ECM (20) Right side connectors for the detonation sensors (21) Right side ignition harness (22) Harness to master ECM connector | |
Engine Control Panel
 | |
| Illustration 6 | g01096133 |
Engine control panel (1) Advisor monitor display (2) Keypad (3) Emergency "stop" button (4) "ENGINE ON" indicator (5) "ACTIVE ALARM" indicator (6) "ENGINE FAILURE" indicator (7) Indicator for prelube (8) Engine control switch (9) Desired speed potentiometer (10) Service tool connector | |
Refer to Systems Operation, Testing and Adjusting, "Engine Control Panel" for the descriptions of the panel controls and displays.
Power Distribution Box
The power distribution box is located on the left side of the engine. The engine electrical power supply and the alternator (if equipped) are connected to lugs that are inside the box. The box also contains five fuses. Refer to Illustration 7.
 | |
| Illustration 7 | g01096525 |
Left side view (1) Power distribution box (2) 20 amp fuse for the throttle actuator (3) 15 amp fuse for the actuator for the compressor bypass (4) 15 amp fuse for the electronic control modules, the advisor, and the service tool (5) 6 amp fuse for the fuel metering valve (6) 6 amp fuse for the keyswitch and the integrated temperature sensing module (7) Connection for the +Battery from the engine power supply (8) Connection for the −Battery to the throttle actuator (9) Connection for the −Battery to the actuator for the compressor bypass (10) Connection for the −Battery to the fuel metering valve (11) Connection for the −Battery to the electronic control modules, the advisor, and the service tool (12) Connection for the −Battery to the electronic control modules, the advisor, and the service tool (13) Connection for the −Battery from the engine power supply | |
Customer Wiring
To wire the engine for requirements of specific application, the customer must be aware of several inputs and outputs associated with the ECM. The following list includes some examples of the inputs and outputs:
- Emergency stop
- Electrical power supply for the control system
- Start-up and shutdown
- Engine speed and governing
- Status of engine operation
There are four options for wiring the engine to the customer equipment:
- P5 connector
- P10 connector via a 9X-4187 Connector Plug As
- 235-2820 Panel Harness As
- Terminal strip inside the engine control panel
The P5 connector is installed at the factory. This connector contains jumper wires that are required in order for the engine to run. Refer to Illustration 8.
| Connections for the Driven Equipment | ||||
| Description | Engine Master J Box Connector | Interconnect Harness ( Wire Identification) | Remote Panel (Terminal Strip) | Function and Comments |
| Emergency Stop | Pin A | C256B-BK | 9 | These terminals must be connected in order for the engine to start. These terminals must remain connected in order for the engine to run. If the ECM is controlling the gas shutoff valve and this circuit is opened, the ECM de-energizes the gas shutoff valve. The fuel is immediately shut off. Additional emergency stop buttons may be added to the emergency stop circuit. For details, refer to "Wiring for the Emergency Stop Circuit". |
| Emergency Stop | Pin B | C256C-BK | 10 | |
| Crank Terminate | Pin C | P696C-WH | 15 | This output is activated when the engines crank terminate speed is achieved. Typically, the crank terminate speed is 250 rpm. The output remains active until the engine speed is reduced to 0 rpm. Normally, the output circuit is open. When the output is activated, the output is grounded. The remote panel does not have an indicator for this output. The sinking driver has a capacity of absorbing a maximum of 0.3 A. |
| Cat Data Link + | Pin D | D100B-RD | 31 | These connections provide the means for communicating the status of the engine control system, of various engine components, and of sensors. The Advisor Monitor Display in the remote panel is connected to these terminals. The Cat Data Link can be connected to the PL1000. For information on connecting the PL1000, refer to the most recent literature for the PL1000. |
| Cat Data Link – | Pin I | D100B-BK | 23 | |
| Desired Speed 4 to 20 mA(+) | Pin E | M500-WH | 40 | The 4 to 20 mA is an optional method for providing the desired engine speed input. If the 4 to 20 mA method is used to control the desired speed, the 0 to 5 VDC input must be disabled. This selection is made on the configuration screen on Cat ET. The 4 to 20 mA input is an isolated input. The "+"input must be in the same circuit as the "-"input. The ECM scales the 4 to 20 mA input range. An input of 4 mA causes the engine rpm to equal the value of the "Minimum High Idle Speed"parameter. An input of 20 mA causes the engine rpm to equal the value of the "Maximum High Idle Speed" parameter. |
| Desired Speed 4 to 20 mA | Pin J | M500-BK | 41 | |
| CAN DATA LINK (+) | Pin F | D200-YL | 33 | The Advisor Monitor Display on the remote panel is connected to these terminals. This data link conforms to the "CAN Data Link 2.0 Hardware Standard" and the "J1939 software Standard". |
| CAN DATA LINK (–) | Pin L | D200-GN | 34 | |
| CAN DATA LINK SHIELD | Pin V | D200-CU | 35 | |
| 4 to 20 mA (+) OUTPUT #1. | Pin G | X000A-RD | 44 | |
| Active Alarm | Pin H | P698C-WH | 16 | This output is activated if the ECM detects an alarm condition. When this output is activated, the output is connected to ground. |
| Normal Stop | Pin K | M010-WH | 25 | This input must be connected to a digital return in order for the engine to operate. This input is not recommended for normal shutdown. The functions of the ECS are recommended for normal shutdown. Connecting the "Input for the COOLDOWN/STOP Mode" to a digital return is the recommended method for initiating a normal shutdown. If the engine is not running and this input is not connected to a digital return, the engine will not crank. No diagnostic codes or event codes are provided for this condition. When the input is removed from the ground, the following shutdown sequence occurs: Power is removed from The GSOV and the fuel is shut off. Power is removed from the ignition system when the engine speed is reduced to less than 50 rpm. The postlube occurs. The cooldown does not operate. |
| 4 to 20 mA (-)OUTPUT # 1. | Pin M | M010-BK | 45 | The preferred method for the desired speed input must be selected with Cat ET. The optional control panel has the appropriate analog speed potentiometer. The wiring must be installed according to the information in this Table. The ECM provides the +5 V supply to the potentiometer. The potentiometer provides the signal input for the desired speed. The signal input ranges from 0 to 5 V. The potentiometer must be in the same circuit as the return. The cable shield must be connected to the signal return. An input of 0 VDC causes the engine rpm to equal the value of the "Minimum High Idle Speed" parameter. An input of 5 VDC causes the engine rpm to equal the value of the "Maximum High Idle Speed"parameter. |
| Desired Speed Analog Supply +5 V | Pin N | M170-RD | 36 | |
| Desired Speed Analog Input | Pin X | M170-WH | 37 | |
| Desired Speed Analog Return | Pin g | M170-BK | 38 | |
| Desired Speed Shield | Pin p | M170-CU | 39 | |
| MCS-STOP | Pin O | P613-BK | 5 | If these inputs are not wired correctly, the ECM will activate a diagnostic code. Typically, these inputs are connected to an engine control switch (ECS). Refer to "Inputs for the Engine's Mode of Operation" for additional information on these inputs. These inputs must be connected to a switch or a logic device. The switch or a logic device must connect the inputs to a digital return. When terminal 6 is connected to the digital return, the ECM will begin the engine start sequence. When terminal 7 is connected to the digital return, the ECM is in "STANDBY" mode. The engine mode of operation is determined by the "Input for the START Mode". When the "Input for the START Mode" terminal 6 is connected to the digital return, the normal sequence for start-up is initiated. When the "Input for the START Mode" is disconnected from a digital return, a normal shutdown is initiated. The ECM remains in the STANDBY Mode. If the engine is running and "Input for the Cooldown/STOP Mode" is connected to digital return, the sequence for normal shutdown is initiated. The shutdown sequence will begin when the terminal 6 is disconnected from the return and terminal 5 is connected to the return. The shutdown sequence is followed by a cooldown period if the time has been programmed in. |
| MCS-START | Pin h | P615C-BK | 6 | |
| MCS-AUTO | Pin Y | P614C-BK | 7 | |
| Digital Return | Pin r | M500D-BK | 8 | This connection provides a return (GND) for various inputs. |
| Engine Failure | Pin P | P698C-WH | 17 | The ECM connects this terminal to ground when the ECM causes the engine to shut down. This output capacity is of sinking 0.3 A. |
| E-STOP Diagnostic-Advisor | Pin R | N900B-BK | 12 | |
| 4 to 20 mA (+)Input | Pin S | X000A-RD | 42 | |
| Manual Prelube | Pin T | C205C-WH | 18 | If the optional control panel is used, the manual prelube switch can be operated when the ECS is in the STOP position. If the prelube is controlled by the customer equipment, the function can be activated by providing a 24 VDC power supply to the input. Activation of the manual prelube switch or 24 VDC power supply will cause the prelube pump to operate. The pump will operate until the switch for prelube oil pressure closes. If either method continues to activate the input, the prelube pump will operate again when the switch for prelube oil pressure opens. |
| Driven Equipment | Pin U | M000-BK | 21 | This input indicates when the driven equipment is ready for operation. This input must be connected to a digital return in order for the engine to crank and/or run the engine. When this input is connected to a digital return, the engine can be started. When this input is not connected to a digital return, the engine will not crank. The ECM generates an event code if this input is not connected to a digital return within the programmed delay time. When the engine is running, this input normally continues to be connected to the digital return. If the engine is running and this input is disconnected from digital return, the ECM immediately generates and event code. The ECM also de-energizes the GSOV. Because the cooldown is not performed, do not use this input for normal shutdown. |
| 4 to 20 mA (+) Output # 2 | Pin W | X100C-RD | 46 | |
| Run Relay | Pin Z | M040-WH | 14 | This output is activated when the engine is cranked. The output remains active until the beginning of an engine shutdown. Normally, when the engine is not running the output circuit is open. When the output is activated, the output is grounded. The "ENGINE ON" indicator on the optional control panel is illuminated. The sinking driver capacity of absorption is maximum of 0.3 A. |
| E-STOP Diagnostic-Advisor | Pin a | N900A-BK | 13 | |
| 4 to 20 mA (-) Input | Pin b | X000B-BK | 43 | |
| Prelube Active Signal | Pin c | A320C-RD | 19 | This output is activated when the ECM requests operations of the prelube pump. The circuit driver has a capacity of supplying 2.0 A at 24 VDC to the prelube pump solenoid. When the output is activated, the "PRELUBE ON" indicator on the optional control panel is illuminated. |
| Idle/Rated Input | Pin d | M030-WH | 22 | When this input is not connected to a digital return, the engine will run at the idle speed "Low Idle Speed" that has been programmed with Cat ET. When the engine oil pressure is greater than the setpoint for the engine speed, the engine will run at the desired speed input. |
| Second Timing | Pin c | M050-BK | 23 | This function is not available for the G3520B. Do not attempt to wire to this connection. |
| 4 to 20 mA (-) #2 Output | Pin f | X100D-BK | 47 | |
| Spare 01 | Pin j | SP01-BK | 51 | |
| PWM Output # 1 | Pin k | X110B-BK | 48 | |
| Gas Shutoff Active Signal | Pin m | A330C-RD | 20 | This output is activated when the pressure switch and when the ECM energizes the GSOV coil. The gas shutoff valve (GSOV) is energized to run. To enable fuel flow to the engine, voltage is supplied to the solenoid for the GSOV. The voltage is removed for an engine shutdown and the output is deactivated. The circuit driver capacity is 2.0 A at 24 VDC. The output can be used to provide a signal for control of multiple valves that are installed by the customer. Alternatively, the signal can be used by the customer monitoring systems. |
| On/Off GRID Switch Input | Pin n | M020-WH | 24 | The settings for the governing are adjusted during the engine commissioning and during the initial start-up. The second governor gains are used primarily for generator sets. When the "GRID SWITCH" is ON (connected to ground), the ECM senses the grounding of the circuit. The ECM governs the engine according to the setting for the auxiliary governing settings. When this input is not grounded to ground, the ECM governs the engine according to the settings for the primary governing. |
| PWM Output # 2 | Pin s | X110A-BK | 49 | |
| Gas Shutoff Return | Pin | A330C-BK | 50 | This terminal connects the GSOV to the digital return and ground. |
| Spare 02 | Pin u | SP02-BK | 52 | |
| Keyswitch | Pin y | P700-RD | 4 | The keyswitch power is available when the ECS is at the STOP, AUTO, or START position. The fused 24 VDC power supply (6 amp) is available to these components and will cause the components to power up: Master ECM Slave ECM Integrated Temperature Sensing Module (ICSM) Optional Control Panel This connection must be powered when the engine control is in "COOLDOWN/STOP", "AUTO", OR "START" when the remote panel is not installed. |
| Spare | The connector is unconnected. | M900A/WH | ||
| Spare | The connector is unconnected. | M900B/WH | ||
| BATT (+) Fused KEY (24 VDC, 6 amp) | Pin w | P100-WH | 3 | This connection is for the system 24 VDC power BATT (+) supply from the customer. This power supply should be circuit protected to this connection. |
| BATT ( - ) (GND) | Pin x | P600-BK | 2 | This connection is for the system 24 VDC power BATT (-) supply from the customer. |
 | |
| Illustration 8 | g01953889 |
P5 jumper wires | |
The 9X-4187 Connector Plug As mates with the J10 connector. This connector is not provided by the factory.
The 235-2820 Panel Harness As connects to the J10 connector. The other end of the harness may be connected to the control panel. Alternatively, the other end of the harness may be connected directly to the wiring from the customer equipment.
The control panel contains a terminal strip. The customer connections may be made to the terminal strip.
Some of the wiring connections are required. Some of the wiring connections are optional. Each connection is illustrated by a schematic in this Special Instruction.
Required Connections
Emergency Stop
 | |
| Illustration 9 | g01221390 |
Wiring for the emergency stop circuit | |
The emergency stop buttons are properly wired in order to stop the engine immediately in case of an emergency situation. An emergency stop button is provided on the engine mounted terminal box. An emergency stop button is provided on the engine control panel.
If the emergency stop button is activated, the fuel is immediately shut off. Electrical power is immediately removed from the ignition system.
| NOTICE |
|---|
Emergency shutoff controls are for EMERGENCY use ONLY. DO NOT use emergency shutoff devices or controls for normal stopping procedure. |
The customer may supply additional emergency stop buttons. The contacts of the emergency stop button are normally closed. Any additional customer supplied emergency stop buttons must be wired in series in order to operate properly. Operation of all emergency stop buttons must be verified during the initial start-up.
If the customer does not use the P5 connector in the engine mounted terminal box, a jumper wire between terminals 48 and 49 is necessary. This jumper wire is provided by the factory.
Desired Engine Speed
 | |
| Illustration 10 | g01948254 |
Wiring for the desired engine speed | |
An input for the desired engine speed is required. The input can be either 0 to 5 VDC or 4 to 20 mA. Use Cat ET to select the input that is used.
An input of 0 VDC or 4 mA causes the engine rpm to equal the value of the "Minimum High Idle Speed" parameter. An input of 5 VDC or 20 mA causes the engine rpm to equal the value of the "Maximum High Idle Speed" parameter.
Driven Equipment Input
 | |
| Illustration 11 | g01221494 |
Wiring for the driven equipment input | |
This input indicates when the driven equipment is ready. When this input is connected to the return, the engine will follow the normal sequence for starting.
When this input is not connected to the return, the engine will not crank.
An event code will be generated if this input is not connected to the return within a time that can be programmed with Cat ET.
If the engine is running and this input is disconnected from the return, the ECM will immediately remove the voltage from the GSOV. The engine will shut down. The engine cooldown will not occur.
Inputs for the Engine Mode of Operation
 | |
| Illustration 12 | g01097414 |
Wiring for the engine mode of operation | |
The engine has four modes of operation. The mode of operation is determined by three inputs on the P1 connector. The valid configurations of the inputs are described in Table 3.
| Valid Configurations of the Terminals for Selection of the Engine Mode of Operation | |||
|---|---|---|---|
| Terminal P1-61 | Terminal P1-64 | Terminal P1-62 | |
| "OFF/RESET" Mode | No (1) | No | No |
| "AUTO" Mode | No | Yes (2) | No |
| "AUTO START" Mode | No | Yes | Yes |
| "START" Mode | No | No | Yes |
| "STOP" Mode | Yes | No | No |
| ( 1 ) | The "No" indicates that the terminal is not connected to the return. |
| ( 2 ) | The "Yes" indicates that the terminal is connected to the return. |
Configurations that are not shown in Table 3 will activate a diagnostic code.
The transition between inputs must occur within 1/10 second. If the transitions do not occur within 1/10 second, a diagnostic code will be activated.
"OFF/RESET" Mode
When none of the inputs are connected, the engine is in the "OFF/RESET" mode. The ECM is off. Any active diagnostic codes are cleared.
"AUTO" Mode
When terminal "P1-64" is connected to the return, the engine is in the "AUTO" mode. The ECM is in standby.
The engine start sequence will be initiated when terminal P1-62 is connected to the return. When terminal P1-62 is disconnected, the shutdown sequence will be initiated. In the "AUTO" mode, terminal P1-62 is used to control both the engine start sequence and the shutdown sequence.
"START" Mode
The engine start sequence will begin when terminal P1-62 is connected to the return.
"STOP" Mode
The shutdown sequence will begin when terminal P1-62 is disconnected from the return and terminal P1-61 is connected to the return. The shutdown sequence is followed by a cooldown period.
Idle/Rated Input
 | |
| Illustration 13 | g01097440 |
Wiring for the idle/rated input | |
The idle/rated switch allows the customer to select between "Low Idle Speed" or "Actual High Idle Speed". Table 4 shows the idle speed selected by the ECM based on the following conditions:
- Position of the idle/rated switch (customer furnished).
- Oil pressure
- Engine speed
| Idle/Rated Switch | ||
| Switch Mode | Conditions (1) | Speed that is Selected by the ECM |
| Open/Idle | Conditions not met | Low Idle Speed |
| Open/Idle | Conditions met | Low Idle Speed |
| Closed/Rated | Conditions not met | Low Idle Speed |
| Closed/Rated | Conditions met | Actual High Idle Speed |
| ( 1 ) | The oil pressure is greater than the low oil pressure alarm level AND the engine speed is greater than the crank terminate speed. |
Input for Engine Stop
 | |
| Illustration 14 | g01948084 |
Wiring for the input for engine stop Typically, terminals P5-26 and P5-27 are connected by a jumper wire that is provided by the customer. | |
This input must be connected to the return in order for the engine to crank.
If the engine is running and this input is disconnected from the return, the ECM will remove electrical power from the GSOV. A cooldown will not occur.
Disconnecting this input from the return is not the recommended method for shutting down the engine. Refer to ""Inputs for the Engine Mode of Operation" " for additional information.
No diagnostic codes or event codes are provided for this input.
Optional Connections
 | |
| Illustration 15 | g01948128 |
Wiring for the optional connections | |
Crank Terminate
The ECM connects this terminal to ground when the engine rpm increases to the crank terminate speed. The crank terminate speed can be programmed with Cat ET. The default value of 250 rpm should be sufficient for most installations. This output capacity is sinking 0.3 A.
Run Relay
The ECM connects this terminal to ground when the engine is cranked. This terminal remains connected to ground until the beginning of engine shutdown. This output capacity is sinking 0.3 A.
When the engine control panel is connected, the green "ENGINE ON" lamp is illuminated via this connection.
Active Alarm
The ECM connects this terminal to ground when the ECM detects an alarm condition. This output capacity is sinking 0.3 A.
When the engine control panel is connected, the amber "ACTIVE ALARM" lamp is illuminated via this connection.
Engine Failure
The ECM connects this terminal to ground when the ECM causes the engine to be shut down. This output capacity is sinking 0.3 A.
When the engine control panel is connected, the red "ENGINE FAILURE" lamp is illuminated via this connection.
Switched +24 VDC
This connection provides a fused +24 VDC power supply for the customer. This connection can provide a maximum of 6 A.
This connection is not powered when the engine control is in the OFF/RESET mode.
Desired Timing
This connection is provided in order to control the base timing of the engine. When this input is an open circuit, the engine will use the "First Desired Timing" as the desired timing. When this input is connected to the return, the engine will use the "Second Desired Timing" as the desired timing.
Cat Data Link
These connections provide the means for communicating the status of the engine control system, of various engine components, and of sensors.
The Cat Data Link can be connected to the PL1000. The following publications are available for detailed information on these modules.
- PL1000E Special Instruction, REHS2362, "Installation Guide for the 256-7512 PL1000E Communications ECM"
- PL1000T Special Instruction, REHS2125, "Installation Guide for the 256-7511 PL1000T Communications ECM"
Wiring for the Gas Shutoff Valve (GSOV)
The GSOV must be energize-to-run. The GSOV may be supplied by the customer or by Caterpillar. Usually, the GSOV is installed with the piping for the fuel at the site. The GSOV may be controlled by the engine control system or by the customer equipment. The GSOV is also called the fuel control relay.
The ECM can supply a maximum continuous current of 1.5 A to the GSOV. A relay must be installed if the GSOV requires a continuous current that is greater than 1.5 A.
When the engine control system controls the GSOV, the ECM supplies voltage to the GSOV. The valve opens in order to allow fuel to flow to the engine. When voltage is removed from the GSOV, the valve closes and the fuel flow stops.
When the customer equipment controls the GSOV, the equipment must include the logic to ensure the GSOV opens and closes at the appropriate times.
Note: So many times the timing for customer controlled devices does not match the ECM timing and problems result.
There are five options for wiring the GSOV. The options are described in the following paragraphs.
The GSOV is controlled by the customer equipment. In this case, the circuit for the engine control system must be a complete path. The circuit must include a resistor. Otherwise, an open circuit diagnostic code will be activated and the engine will not start. Refer to Illustration 16 for an example of this type of installation.
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| Illustration 16 | g01221498 |
The GSOV is controlled by the customer equipment. In this configuration, the circuit must include a resistor. The resistor may be installed anywhere in the circuit. A typical installation is shown. | |
The GSOV is controlled by the engine control system. The customer may supply an additional switch in the electrical circuit for the GSOV. The additional switch may be placed anywhere in the circuit. Refer to Illustration 17 for an example of each type of installation.
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| Illustration 17 | g01097664 |
The GSOV is controlled by the engine control system. | |
Initial Start-Up Procedure
Ensure that all of these factors are in proper working condition prior to the initial start-up: engine installation, driven equipment, all of the related hardware and electrical connections. Failure to perform the commissioning procedure could result in unsatisfactory operation.
Perform the following procedure for the initial start-up and for start-up after major maintenance and/or after repair.
Note: Use Cat ET version 2008C or later.
- Current fuel analysis
Obtain a fuel analysis and calculate the methane number for air/fuel ratio control.
- Methane number for determining desired timing
- Fuel quality value for engine setup
- Gas specific gravity for engine setup
- Fuel specific heat ratio for engine setup.
- Methane number for determining desired timing
- Connect Cat ET to the service tool connector. Establish communications with the master ECM. Go to the Air/Fuel Ratio setup screen and set the Air/Fuel Proportional and the Air/Fuel Integral input value to 0.
- Set the first desired ignition timing by using the methane number and the fuel usage for this engine "Refer to the correct performance data sheet".
- Set the engine speed control.
- Set the governor control to Isochronous.
- Set minimum high idle to 1050 rpm
- Set maximum high idle to 1400 rpm
- Set governor proportional gain (P) to 100 percent
- Set the governor integral stability (I) to 100 percent
- Set the governor control to Isochronous.
- Adjust the fuel supply pressure to the engine regulator to 32 to 35 (Psig), with a maximum setting of 40 (Psig).
- Adjust the fuel supply pressure to the fuel valve between one and five Psig. The target pressure should be 2.5 psig. The fuel supply pressure on ET can be read as the fuel supply pressure minus the atmospheric pressure.
- Calibrate the NOxsensor.
Note: If the engine air/fuel ratio is not correct, you cannot calibrate the NOx sensor now in step 7.
Perform the following procedure in order to calibrate the NOx sensor :
- Start the engine. Allow the engine to warm to normal operating temperature. Increase the engine speed to a minimum of high idle. Set the engine load to 50 percent.
- Connect a 156-1060 Emissions Analyzer Gp or a 156-1070 Emissions Analyzer Gp (or equivalent) to the engines exhaust system. Allow the NOx readings from the analyzer to stabilize.
- Access the "service/calibrations/engine exhaust NOx level sensor calibration" screen of Cat ET. Use Cat ET to start the calibration.
- Follow the prompts in order to guide you through the calibration procedure.
- Compare the value of the NOx that is reported from Cat ET to the value that is reported from the exhaust analyzer. Select the arrow buttons at the bottom of the calibration screen in order to increase or decrease the slope sensor value that is reported by Cat ET.
Note: Make small changes to the slope value during the calibration procedure. If large changes are made to the slope value, the engine operation may become unstable. Allow the engine to stabilize after each adjustment is made. When the values are comparable within ±10 PPM, click the "Next" button at the bottom of the screen.
- Cat ET will prompt you to allow the engine to stabilize for 3 minutes in order to verify the correct settings.
- If necessary, perform the calibration procedure again in order to recalibrate the sensor.
- Stop the engine and allow the turbochargers to cool down before installing the speed sensor.
- Turbocharger speed measurement and setup procedure
- Remove all debris from the threaded plug and the surrounding area. Foreign material must be kept out of the turbocharger housing.
- Remove the threaded plug and the o-ring seal. Store the plug in a clean place in order to be reinstalled.
- By using a deep well socket to prevent damage to the speed sensor, torque the speed sensor to 12 to 15 N·m (8.85 to 11 ft lb).
- Once the pins are aligned correctly, attach the 344-2650 Wiring Harness by pushing down the bayonet type lock ring connector and twisting until locked.
Show/hide table
Illustration 18 g01945818
(1) 343-3320 Speed Sensor
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Illustration 19 g01945820
(2) The bayonet type lock ring is installed.
- Connect the sensor harness to the Multimeter. The black plug is ground and the red plug is the signal. Set the multimeter to 60 ACV range frequency measurement.
- Start the engine and gradually apply a load in order to match any of the following combinations for the respective emission settings.
Note: Set the engine to 1400 rpm and 100 percent load.
For 0.5 g NOx setting
- Engine speed of 1400 rpm with a load of 100 percent Refer to illustration 20.
- Engine speed of 1400 rpm with a load of 90 percent Refer to illustration 21.
- Engine speed of 1400 rpm with a load of 80 percent Refer to illustration 22.
- Engine speed of 1400 rpm with a load of 75 percent Refer to illustration 23.
- Engine speed of 1200 rpm with a load of 100 percent Refer to illustration 24.
- Engine speed of 1200 rpm with a load of 90 percent Refer to illustration 25.
- Engine speed of 1200 rpm with a load of 80 percent Refer to illustration 26.
For 1 g NOx setting
- Engine speed of 1400 rpm with a load of 100 percent Refer to illustration 27.
- Engine speed of 1400 rpm with a load of 85 percent Refer to illustration 28.
- Engine speed of 1400 rpm with a load of 75 percent Refer to illustration 29.
- Engine speed of 1200 rpm with a load of 100 percent Refer to illustration 30.
- Engine speed of 1200 rpm with a load of 85 percent Refer to illustration 31.
- Engine speed of 1400 rpm with a load of 100 percent Refer to illustration 20.
- Check the ambient temperature, site altitude, and emission setting.
Note: The speed of the turbocharger will increase with an increase in temperature. For a given speed, load, emission setting, and altitude.
Show/hide tableTable 5 Ndesired = Nmax x Fcorr Ndesired - Desired turbocharger speed in Hz
Nmax - Maximum turbocharger speed from setup charts in Hz
Fcorr - Temperature correction factor from Table 6
- Determine the maximum turbocharger speed (Nmax) in Hz from the setup charts for particular emission settings, engine speed, load, and altitude. Then, use Table 6 to determine the temperature correction factor (Fcorr). Apply the correct formula from table 5in order to determine the desired turbocharger speed (Ndesired).
Set the engine to run at the desired turbocharger speed (N desired) calculated from the above equation.
- Adjust the wastegate so the turbocharger speed reading from the multimeter matches with the desired turbocharger speed (Ndesired).
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Table 6 Temperature correction factor look-up. Tcurrent / Current Temperature Tmax / Max Temp for Month 32 -40 41 - 49 50 - 58 59 - 67 68 - 76 77 - 85 86 - 94 95 - 103 104 - 112 113 - 121 122 - 130 131 32 -40 1.000 41 - 49 .986 1.000 50 - 58 .972 .986 1.000 59 - 67 .958 .973 .986 1.000 68 - 76 .946 .960 .973 .987 1.000 77 - 85 .934 .947 .961 .974 .987 1.000 86 - 94 .922 .935 .949 .962 .975 .987 1.000 95 - 103 .910 .924 .937 .950 .963 .975 .988 1.000 104 - 112 .899 .913 .926 .938 .951 .964 .976 .988 1.000 113 - 121 .889 .902 .915 .927 .940 .952 .964 .976 .988 1.000 122 - 130 .879 .892 .904 .917 .929 .941 .953 .965 .977 .989 1.000 131 .869 .882 .894 .907 .919 .931 .943 .954 .966 .977 .989 1.000 Tmax - Maximum ambient temperature for the month in deg F
Tcurrent - Current ambient temperature in deg F
- Check the Fuel Correction Factor (FCF).
- The FCF needs to be at 100 percent ± 5 percent above 50 percent load. If the FCF is not correct, adjust the fuel quality value in Cat ET until an FCF of 100 percent is attained.
Recheck the turbocharger speed, if not acceptable return to step 8.
- The FCF needs to be at 100 percent ± 5 percent above 50 percent load. If the FCF is not correct, adjust the fuel quality value in Cat ET until an FCF of 100 percent is attained.
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| Illustration 20 | g01944385 |
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| Illustration 21 | g01944396 |
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| Illustration 22 | g01944402 |
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| Illustration 23 | g01944408 |
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| Illustration 24 | g01944410 |
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| Illustration 25 | g01944413 |
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| Illustration 26 | g01944415 |
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| Illustration 27 | g01944416 |
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| Illustration 28 | g01944417 |
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| Illustration 29 | g01944418 |
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| Illustration 30 | g01944419 |
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| Illustration 31 | g01944420 |
- Check emissions.
By using ET, monitor the NOx PPM. The NOx PPM screen will display the value shown on the analyzer (±10 PPM) for a 5 minute period. If not, return to step 7.
- Remove the turbocharger speed sensor.
- Stop the engine and Allow To Cool! Then access the sensor and the wiring harness.
- Remove the wiring harness by unlocking the bayonet type lock ring and remove the harness away from the engine.
- Clean the area around the speed sensor and the speed sensor connector.
- Remove the speed sensor by using a deep well socket in order to prevent damage.
- Inspect the threaded plug and the O-ring. Replace the o-ring if necessary with Parker 0036-6087. Verify that the plug is free of debris.
- Install the threaded O-ring plug and torque to 10 N·m (7 lb ft) to 15 N·m (11 lb ft).
- Start the engine and set the engine to the desired speed and load.
Adjusting the Governor
The response of the throttle actuator can be adjusted with Cat ET. Use Cat ET to change these three parameters:
- Governor Proportional Gain Factor
- Governor Integral Stability Factor
- Governor Derivative Compensation Factor
For details on these parameters, refer to Systems Operation, Testing and Adjusting, "Electronic Control System Parameters".
The default values should be sufficient for initial start-up. However, the values may not provide optimum performance.
These adjustments are provided in order to obtain optimum responses to changes in the engine load and in the engine speed. The adjustments also provide stability during steady state operation.
If you have a problem with instability, always investigate other causes before you adjust the governor. For example, diagnostic codes and unstable gas pressure can cause instability.
To change the proportional gain, the integral gain, or the derivative gain, use the "Real Time Graphing" feature on the "Information" drop-down menu of Cat ET. The graph provides the best method for observing the effects of your adjustments.
After you make adjustments, always test the stability by interrupting the engine speed and/or load. Operate the engine through the entire range of speeds and of loads in order to ensure stability.
Note: Adjustment of proportional gain affects speed of the throttle actuator when there is a difference between actual engine speed and desired speed. An excessive increase of the proportional gain may amplify instability.
To set the proportional gain, increase the proportional gain until the throttle actuator becomes unstable. Slowly reduce the proportional gain in order to stabilize the actuator. Observe that the engine operates properly with little overshoot or undershoot.
The adjustment of integral gain dampens the throttle actuator response to changes in load and in speed. Increasing the integral gain provides less damping. Decreasing the integral gain provides more damping. To reduce overshoot, decrease the integral gain. For reduction of undershoot, increase the integral gain.
Note: An increase of the integral gain may require a decrease of the proportional gain in order to maintain engine stability.
Illustration 32 shows some typical curves for transient responses.
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| Illustration 32 | g01017530 |
Typical curves for transient responses (Y) Engine speed (X) Time (1) The proportional gain is too high and the integral gain is too low. There is a large overshoot on start-up and there are secondary overshoots on transient loads. (2) The proportional gain is slightly high and the integral gain is slightly low. There is a slight overshoot on start-up but the response to transient loads is optimum. (3) The proportional gain is slightly low and the integral gain is slightly high. There is optimum performance on start-up but slow response for transient loads. (4) The proportional gain is too low and the integral gain is too high. The response for transient loads is too slow. (5) The response to transient loads is adjusted for optimum performance. | |
Decrease the derivative gain until a slow, periodic instability is observed. Then, slightly increase the derivative gain. Repeat the adjustments of the proportional gain and of the integral gain. Continue to increase derivative gain and readjust the proportional gain and integral gain until stability is achieved. The engine response to changes in load and in speed is optimized.
Illustration 33 is a graphic representation of adjusting the derivative gain.
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| Illustration 33 | g01017541 |
The increased width of the line for the actuator voltage indicates that the throttle actuator is more active as the derivative gain increases. (Y) Actuator voltage (X) Time in seconds | |
Unburned Gas − Purge
The following events cause unburned gas to remain in the air inlet and in the exhaust manifold:
- Emergency stop
- Engine overspeed
- The engine control is set to the STOP mode and the gas shutoff valve does not close.
- Unsuccessful successive attempts to start the engine
Unburned gas may remain in the air inlet and exhaust system after several unsuccessful attempts to start the engine. The unburned gas may increase to a concentration that may ignite during a successive attempt to start the engine.
Perform the following procedure in order to purge the unburned gas:
- Connect Cat ET to the engine.
- Verify that the value of the "Engine Purge Cycle" parameter is equal to 10 seconds less than the value of the "Crank Cycle" parameter.
- Set the engine control to the START mode. The engine will crank for the "Engine Purge Cycle" time. Then, the gas shutoff valve will be energized and the ignition will be enabled. The engine will start. Continue with normal operation.