EMCP4.1/EMCP4.2 Caterpillar

Illustration 1	g02278314

Thermocouple Specifications

Electrical Specifications

• Accept 5-32 VDC power (12 VDC or 24 VDC nominal)

• Over voltage capability is 32 VDC for 1 hour at 85° C (185° F)

• Power supply inputs are protected against transient surges and short circuits and are isolated from I/O

• Three-way isolation is provided for the CAN line, inputs, and power supply

• Burden is limited to less than 200 mA, inrush not to exceed 800 mA

• Common mode rejection is -80 db@ 5V p-p (50-60 Hz)

• Common mode input range is +/- 4 V minimum

• Designed to meet relevant European standards for EMI/RFI/Immunity without the use of external filtering

Network Communications Interface

• Capable of operating on the EMCP 4 accessory CAN 2 data link

• Node address is auto configurable

• Optical isolation is provided for the CAN line

• Retains current date and time relative to synchronization every 24 hours (or upon boot up) with equipment system time via an explicit command from the EMCP 4 or Cat ET when the GSC is not available. Synchronization time is accurate to within 1 sec

• Includes a watchdog timer to automatically reboot should the microprocessor lock

• Module operates normally with loss of communication link, retaining configured values and error codes in non-volatile memory

• Configuration and firmware updates are accomplished with Cat ET over the CAN network

Thermocouple Wiring

Illustration 2	g02278333
Connector Contact Description (1) Power (2) CAN High (3) CAN Low (4) Ground (5) Shield (6) Not Used (7) Not Used (8) Not Used

Illustration 3	g02278334
Thermocouple Sensor Wiring

Thermocouple Configuration

The thermocouple module is field programmable using Cat ET. It is also flash programmable to update software using Cat ET.

Illustration 4	g02278335

The service tool software must be installed on a Windows PC. The communication adapter must be connected between the PC and the CAN data link on which the target thermocouple module is connected. When connecting the thermocouple module, the user will first see the "ECM Summary" screen shown in Illustration 4.

The service tool configuration tool contains setpoints for configuring the thermocouple module identification, as well as the thermocouple inputs.

Note: "ECU Instance #1" is reversed for the accessory data link (CAN 2), while "ECU Instance #2" is reserved for the primary data link (CAN 1).

Illustration 5	g02278336

Illustration 5 shows the ECM identification parameters list. This list shows the ECM serial number (read-only) of the module that is connected, and allows for configuration of the ECU instance. Each thermocouple module on the data link must have a unique ECU instance. If ECU instances are duplicated, one of the modules must be disconnected and the other reconfigured to a different ECU instance.

Illustration 6	g02278337

Upon changing the ECU instance, Cat ET will automatically reconnect to the data link, and the thermocouple module name should reflect the new ECU instance. In this example, as shown in Illustration 6, the module was previously named "Thermocouple Module #1", and after the ECU instance is changed to 2 and the service tool reconnects, the name reads "Thermocouple Module #2".

Configuring Thermocouple Inputs

Illustration 7	g02278338

Illustration 7 shows the "Thermocouple Input #1" configuration list. All 20 thermocouple inputs have identical parameters and options.

The "Sensor Type Configuration" selects either a J or K type configuration. Select the appropriate configuration based on the type of thermocouple installed. Reference Specification Sheet, LEHE0126 for available temperature inputs.

The Suspect Parameter Number (SPN) is a numerical entry between a predetermined list of SPNs that are supported by the thermocouple module. All of the thermocouple inputs support the same list of SPNs. To change the SPN, type in the number that corresponds with the desired parameter. Refer to Table 4 for specific information on what possible SPN values can be used.

Illustration 8	g02278340

The "High Temperature Shutdown Event Threshold" sets the high temperature at which a high shutdown event will occur.

The "High Temperature Warning Event Threshold" sets the high temperature at which a high warning event will occur.

The "Low Temperature Warning Event Threshold" sets the low temperature at which a low warning event will occur.

The "Event Notification Delay Time" sets the amount of time the threshold must be exceeded until the Thermocouple module triggers that particular event on the data link. Each of the delay time options corresponds with a particular event type.

Table 1 lists the configuration parameters for the thermocouple inputs.

Diagnostics

The thermocouple module can generate events and diagnostics and can store up to 20 diagnostic log entries that can be viewed from the EMCP 4. The generated events and diagnostics are maintained in non-volatile memory in order to ensure availability after a power loss. The format for each of the log entries is listed in Table 2.

Twenty thermocouple inputs can be connected to a thermocouple module. The module can detect both open circuits and short circuits for any of the 20 inputs.

Additionally, the module detects overtemperature warnings and shutdowns, as well as under temperature warnings. These warnings are detected by comparing the measured temperature to the low warning, high warning, and high shutdown temperature thresholds that are programmed in the module.

The diagnostic messages listed in Table 3 are broadcast on the CAN data link. The EMCP 4 controller reads these messages and can provide both an annunciation for the operator and can also perform a soft shutdown of the engine as appropriate. Any of the inputs can be disabled in order to prevent unnecessary diagnostic faults.

Monitoring Features

Thermocouples are given a type designation that is based on the range of temperatures that the thermocouple can accurately measure. The thermocouple module monitors 20 "Type-J" or "Type-K" thermocouple inputs.

Each input can be configured and can be set to any SAE CAN Suspect Parameter Number (SPN) that is listed in Table 4. An SPN is an internationally recognized code that is designated with a specific meaning. For example, SPN174 is designated as "Fuel Temperature".

The display units are selectable at the EMCP 4 controller as either degrees fahrenheit or as celsius. All monitored values are available on the data link as read-only information. Temperatures are configured to indicate the SPN that is transmitted by each temperature input.