EMCP4.1/EMCP4.2 Caterpillar

• Primary CAN Data Link (CAN 1)

• Accessory CAN Data Link (EMCP 4.2 only) (CAN 2)

• Modbus RTU (RS-485 Half duplex)-SCADA Data Link (EMCP 4.2 only)

• RS-485 SCADA Data Link (Modbus RTU, Half Duplex) (EMCP 4.2 only)

Primary CAN Data Link (CAN 1)

A communications connection, utilizing CAN 1, is available on the module. The communications connection allows configuration of set points, flashing of the core software, and language text files. The configuration software has password protection for different authorization levels. Configuration of set points will also be possible using the controls on the module. Configuration of set points is made possible by utilizing the same password strategy used across the control system range.

The connection will also be utilized for communicating with the engine control module (ECM) using the CAN protocol.

This connection will also be utilized for communicating with automatic voltage regulators (AVR) using the CAN protocol when the AVR support this protocol. An example of an AVR is the Caterpillar Digital Voltage Regulator (CDVR).

This connection also provides communications for on-package expansion thermocouple modules for use with monitoring of engine temperatures.

This connection will also provide communications for the Caterpillar Clean Emissions Module System.

The primary CAN communication wires are brought out of the EMCP 4 as part of the 70-pin connector. The pins, as designated on the EMCP 4 connector, are shown in Table 1.

The primary CAN data link consists of a main trunk and small drops.

• The maximum allowable trunk length is 40 m (130 ft), and the maximum drop length is 1 m (3 ft).

• The CAN network requires a 120 ohm termination resistor on the extreme ends of the main trunk.

An example of the topology for the EMCP 4.1 is shown in Illustration 1.

Illustration 1	g02254093
EMCP 4.1 CAN 1 Wiring Diagram

Accessory CAN Data Link (CAN 2)

Note: The accessory CAN data link (CAN2) is supported only by EMCP 4.2.

An accessory data link connection is provided for use with the local and remote, fixed output annunciator options. This connection can be at a distance of up to 250 m (800 ft) from the control module. The connection will support a maximum of four CAN annunciators modules. This data link is for Caterpillar approved modules only.

A connection is provided for use with the digital expansion input/output modules.

A connection is provided for use with the generator Thermocouple and RTD modules.

The total number of optional modules should not exceed four annunciators, four I/O modules, and two temperature modules. Table 2 lists the supported modules for the CAN 1 and CAN 2 datalinks.

The accessory CAN communication wires are brought out of the EMCP 4.2 as part of the 70-pin connector. The pins, as designated on the EMCP 4 connector, are shown in Table 3

The accessory CAN data link consists of a main trunk and small drops.

• The maximum allowable trunk length is 250 m (800 ft), and the maximum drop length is 3 m (9 ft).

• The CAN network requires a 120 ohm termination resistor on the extreme ends of the main trunk.

The topology for the EMCP 4.2 with some remote devices connected, is shown in Illustration 2.

Note: The devices that are shown in Illustration 2 are only representative. More remote devices can be connected. However, the proper lengths must be maintained and the termination resistor must be placed at the end of the trunk.

Illustration 2	g02254316

RS-485 SCADA Data Link (Modbus RTU, Half Duplex)

Note: Modbus RTU is only supported by EMCP 4.2.

The EMCP 4.2 has an RS-485 Modbus RTU data link for customer monitoring and control. The data link will allow for remote monitoring of all parameter data visible on the display and the service tool. The data link also allows for data link based control of outputs. The RS-485 Modbus RTU functionality is based on the EMCP 4 platform implementation. The EMCP 4 provides a broader range of parameters supported due to the enhanced functionality of the EMCP 4 platform.

RS-485 Annunciator Data Link (EMCP 4.2 only)

The RS-485 module provides communications via proprietary protocol that uses 1 x fully isolated RS-485 2-wire half duplex communications data link. The communications protocol allows interface to optional remote annunciators running at 19.2k baud rate. The communication link is designed for 1200 m (4000 ft) or more. The data link is limited on the amount of information transmitted. The data link will not support the full flexibility of the current accessory data link CAN annunciators that are still available.