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26SI Series Alternator – Diagnostic Capabilities

The Caterpillar Electronic Technician (ET)

The Caterpillar Electronic Technician (ET) is a software program that can be used on an IBM compatible personal computer. Cat ET is used to communicate to, and access data from the ECM over the data link by connecting to the service tool connector. Refer to the “Electrical System Schematic” section of this document in order to locate the service tool connector for a specific application.

The service technician can use Cat ET in order to perform maintenance work on the engine. Some of the options that are available with Cat ET are listed below:

  • View the status of parameters

  • Perform calibration of engine systems

  • Program the ECM (Flash)

  • Print reports

Note: In order to “Flash” program the ECM, use the “WINflash” program. Refer to the “Electronic Control Module (ECM) – Flash Program” section of this document for information about the process to flash program the ECM.

The following list contains some of the diagnostic functions and programming functions that are performed by the service tools.

  • The failures of the ECM system are displayed.

  • The status of most of the inputs and the outputs are displayed.

  • The settings for the ECM are displayed.

  • Display the status of the input and output parameters in real time.

  • Display the clock hour of the internal diagnostic clock.

  • Load new FLASH software.

Status Groups For The Electronic Technician

Cat ET is used as the primary reference in the discussion and Illustrations that follow. The reference to the Cat ET also implies a reference to the Caterpillar Communication Tool Kit when features are common between the two.

Status Group 1 – Serial Port Statistics

Illustration 1 g01397803

Serial Port Statistics screens 1 and 2

The PL1000E tracks the communications on its physical ports. The PL1000E displays the communications statistics on the Cat ET “Serial Port Statistics” screens. The first of the screens displays the communication statistics for serial ports 1, 2, and 3, that is, RS-232 Port 1, RS-232 Port 2, and RS-232 Port 3 respectively.

The second of these screens displays the communication statistics for serial port 4 which is the RS-422 and 485 port. For each serial port, the physical layer bytes that are received, physical layer bytes that are transmitted, the physical layer receive errors, and the physical layer transmit errors are displayed. This information represents the communication statistics of the physical port and may include counts of bytes received or transmitted from various protocols on the same physical port. The physical communication statistics is a good tool to use to verify the ECM is successfully receiving data at the most basic level. The communication statistics on this page are automatically updated by the ECM every 1 second. These totals are the accumulated totals since the last “warm boot sequence” or “cold boot sequence” of the ECM (Keyswitch or power cycle). These totals are not “Lifetime” totals and will be reset with each “boot sequence” of the ECM. The “Clear Counters” button (password protected) simply forces these values to all zeros without the need for a “warm boot” or “cold boot”.

Physical Layer Bytes Received (Rx Bytes) – The total number of bytes successfully received on the physical port. These byte counts may represent bytes received across various protocols on the same port.

Physical Layer Bytes Transmitted (Tx Bytes) – The total number of bytes successfully transmitted on the physical port. These byte counts may represent bytes transmitted across various protocols on the same physical port.

Physical Layer Receive Errors (Rx Errors) – The total number of errors that have been identified by the ECM while attempting to receive data on the physical port. These errors can be caused by incorrect baud rate or other port configurations. The lack of receive errors does not necessarily indicate that protocol communications are successful. It simply indicates that all individual bytes are being received successfully. Successful communications still depends on the communication protocols and the transmitting device’s adherence to the same.

Physical Layer Transmit Errors (Tx Errors) – The total number of errors that have been identified by the ECM while attempting to transmit data on the physical port. These errors can be caused by incorrect baud rate and other port configurations, faulty wiring, or incorrect ECM configuration. The lack of transmit errors does not necessarily indicate that protocol communications are successful. It simply indicates that the ECM is able to successfully transmit the individual bytes. Successful communications still depend on the communication protocols and the receiving device’s adherence to the same.

Status Group 2- Modbus Statistics

Illustration 2 g01397805

Modbus Statistics screens 1 and 2

The PL1000E tracks all Modbus communications on all configured ports and displays the communication statistics on the Cat ET “Modbus Statistics” screens. The first of these screens displays the communication statistics for “Serial Port 1” (RS-232 Port 1) and “Serial Port 2” (RS-232 Port 2).

The second of these screens displays the communication statistics for “Serial Port 4” (RS-422/485). The third displays communication statistics for “Modbus TCP” over the Ethernet port. All of the totals that are displayed on these screens represent the total accumulations since the last “warm boot sequence” or “cold boot sequence” of the ECM. The totals are not lifetime totals and will be reset with each “warm boot sequence” of the ECM.

Modbus RTU Messages Received – The total number of valid, properly formatted Modbus messages successfully received on the communications port.

Modbus RTU Receive Errors – The total number of errors identified by the ECM while attempting to receive “Modbus” messages on the communications port. These errors can be caused by incorrectly formatted messages being transmitted by the “Modbus Master” or another “Modbus Slave” connected to the communications port. Additionally, these errors may be caused by requests for registers or “Modbus Function Code” not supported by the ECM.

Modbus RTU Messages Transmitted – The total number of messages successfully transmitted by the ECM on the communications port.

Modbus RTU Transmit Errors – The total number of errors identified by the ECM while attempting to transmit Modbus messages on the communications port.

Modbus RTU no response – Every time the ECM receives a valid properly formatted Modbus message, the ECM increments this counter. Each time the ECM transmits a “Modbus Message”, the ECM decrements this counter. The increment and decrement actions occur within milliseconds and are typically not viewable on the status screen. However, if this value is other than zero, this would indicate the ECM is receiving Modbus messages and not responding. The ECM configuration should be verified and the PCL file should be reviewed to insure the desired parameters and Modbus communications are configured appropriately.

Illustration 3 g01721473

Modbus Statistics screen 3

Modbus TCP packets received – The total number of valid properly formatted “Modbus TCP” packets successfully received by the PL1000E over the Ethernet port.

Modbus TCP Receive Errors – The total number of errors identified by the ECM while attempting to receive “Modbus TCP” packets on the Ethernet port. These errors can be caused by incorrectly formatted messages being transmitted by the “Modbus Master” or another “Modbus Slave” connected to the Ethernet port. Additionally, these errors may be caused by requests for registers or “Modbus Function” code not supported by the ECM.

Modbus TCP packets transmitted – The total number of “Modbus TCP” packets successfully transmitted by the ECM on the Ethernet port.

Modbus TCP transmit errors – The total number of errors identified by the ECM while attempting to transmit Modbus messages on the communications port.

Modbus TCP no responses – Every time the ECM receives a valid, properly formatted Modbus message, the ECM increments this counter. Each time the ECM transmits a Modbus message, the ECM decrements this counter. The increment and decrement actions occur within milliseconds and are typically not viewable on the status screen. However, if this value is other than zero this would indicate the ECM is receiving Modbus messages and not responding. The ECM configuration should be verified and the PCL file should be reviewed in order to insure the desired parameters and Modbus communications are configured appropriately.

Modbus TCP connections – The total number of “Active Modbus TCP” connections identified and being serviced by the ECM on the Ethernet port. The ECM is capable of supporting up to 10 “Modbus TCP” connections at the same time.

Modbus RTU packets received – The total number of RTU messages received successfully by the ECM. These totals represent all Modbus RTU messages received on all configured Modbus ports. The ports are “RS-232 Port 1”, “RS-232 Port 2”, and the “RS-422/485 Port”. The ECM does not include any message counts from “Modbus TCP” messages received that are on the Ethernet port.

Modbus RTU receive errors – The total number of “Modbus RTU” messages received by the ECM determined to contain incorrect checksum information. These totals represent all “Modbus RTU” receive errors received on all configured Modbus ports. The ports are “RS-232 Port 1”, “RS-232 Port 2”, and the “RS-422/485 Port”. The ECM does not include any message counts from “Modbus TCP” receive errors received on the Ethernet port.

Modbus RTU packets transmitted – The total number of “Modbus RTU” messages transmitted successfully by the ECM. These totals represent all “Modbus RTU” messages transmitted on all configured Modbus ports. The ports are “RS-232 Port 1”, “RS-232 Port 2”, and the “RS-422/485 Port”. The ECM does not include any message counts from “Modbus TCP” messages transmitted on the Ethernet port.

Modbus RTU transmit errors – The total number of “Modbus RTU” exception messages transmitted by the ECM. These totals represent all “Modbus RTU” exception messages that are transmitted on all configured Modbus ports. The ports are “RS-232 Port 1”, “RS-232 Port 2”, and the “RS-422/485 Port”. The ECM does not include any message counts from “Modbus TCP” exception messages transmitted on the Ethernet port. An exception message will be transmitted under the following conditions:

  • The ECM receives a Modbus function code it does not support. The ECM supports the following function codes: 3 = “Read Holding Register”, 6 = “Write Single Register”, 8 = “Diagnostics”, 16 = “Write Multiple Registers”.

  • The ECM receives a Modbus request for a register outside of the supported register ranges. The ECM supports registers in the range of 40,001 to 42000.

Modbus RTU no responses – The total number of “Modbus RTU” messages received successfully by the ECM for which the ECM has not transmitted a response. These totals represent all Modbus no responses on all configured Modbus ports. The ports are “RS-232 Port 1”, “RS-232 Port 2”, and the “RS-422/485 Port”.

Status Group 3- Cat Data Link (CDL) Statistics

Illustration 4 g01721475

CDL Statistics screen.

CDL packets received – The total number of valid properly formatted messages successfully received on Cat Data Link (CDL) by the PL1000E Communication ECM.

CDL receive errors – The total number of errors identified by the ECM while attempting to receive a CDL message. An increment of this number can indicate improper CDL harnessing. CDL harness pin-outs and total bus length should be analyzed.

CDL packets transmitted – The total number of messages successfully transmitted on CDL by the ECM.

CDL transmit errors – The total number of errors identified by the ECM while attempting to transmit a CDL message. An increment of this number can indicate improper CDL harnessing. The harness should be analyzed and repaired.

Status Group 3- J1939 Statistics

Illustration 5 g01721476

J1939 Statistics screen.

J1939 packets received – The total number of valid properly formatted messages successfully received on J1939 by the PL1000E Communication ECM.

J1939 receive errors – The total number of errors identified by the ECM while attempting to receive a J1939 message. An increment of this number can indicate improper J1939 harnessing. J1939 harness pin-outs and total bus length should be analyzed.

J1939 packets transmitted – The total number of messages successfully transmitted on J1939 by the ECM.

J1939 transmit errors – The total number of errors identified by the ECM while attempting to transmit a J1939 message. An increment of this number can indicate improper J1939 harnessing. The harness should be analyzed and repaired.


Messaging Statistics Quick Reference Troubleshooting Guide

Illustration 6 g01180273