PISTON 8D4291 - Caterpillar

PL1000E Communication ECM Modbus Interface Overview
The PL1000E supports a subset of the common Modbus Function Codes that are used for data transfer. Table 1 documents the Function Codes and the addressing ranges which are supported by the PL1000E. The specific Modbus Registers in each application will vary depending on the configuration in the Parameter Translation Editor (PTE).
Table 1
Function Code     Description     Modbus Address Range    
3     Read Holding Registers     40001 through 42000 inclusive    
6     Preset Single Register     40001 through 42000 inclusive    
16     Preset Multiple Registers     40001 through 42000 inclusive    Modbus Parameter Translation Data Location and Formats
The PL1000E Communication ECM provides parameter translations of Cat Data Link and J1939 data to Modbus.The data that is provided on the Modbus Communication Link has the same scaling as the source data link. The Modbus application can use the scaling information in order to transform the data to a value that can be displayed.Each parameter that is defined in the PCL file has a starting Modbus Register. Each parameter that is defined in the PCL file has an associated number of registers that are required to house the data.The data is housed according to the source data link definition and according to the data length definition. The process to house the data applies to all of the parameters with the exception of Events and Diagnostics.The next section covers the format, length, and definition of the Event and Diagnostic data as the data is presented to the Modbus interface.Events and Diagnostics
Event and Diagnostic information is internally retrieved and tabulated by the PL1000E if the Event and Diagnostic parameter translations were included in the PCL file. Event or Diagnostic parameter translations can also be defined independently. Therefore, the user can only configure translations for diagnostics that are desired.Event and Parameter Translations - Cat Data Link Event and Diagnostic Codes
Different versions of ECMs that are on Cat Data Link and J1939 are capable of transmitting the event and diagnostic information in multiple versions of communication protocols.The different communication protocols are managed internally by the PL1000E. The Modbus application does not need to be aware of these communication differences. The PL1000E determines the appropriate communication method from the source data link. The PL1000E presents a list of event and diagnostic data that is consistent regardless of the source data link communication method.The tables for each type of code are very similar. However, there is some additional information that is available or required for certain codes. The additional information dictated minor differences in the table format and content. The events and diagnostics are available in the following form beginning at the starting Modbus Register as defined in the PCL file. If the CDL Event Translations were configured in the PCL file to begin at Modbus Register 40,207, then referring to Table 5, offset zero (0) would be available at Modbus Register 40,207. Offset 1 would be available at 40,208.
Table 2
Cat Data Link Events    
Modbus Register Offset