ProSoft Technology MVI46-MCM - Manual (Page 56)

Diagnostics and Troubleshooting MVI46-MCM ♦ SLC Platform
User Manual Modbus Communication Module
Page 56 of 108 ProSoft Technology, Inc.
March 29, 2011
Module Communication Error Codes
Code Description
-1 CTS modem control line not set before transmit
-2 Timeout while transmitting message
-11 Timeout waiting for response after request
253 Incorrect Slave address in response
254 Incorrect function code in response
255 Invalid CRC/LRC value in response
"Module Communication Errors" are generated by the MVI46-MCM module, and
indicate communication errors with the Slave device.
Error Code -11 indicates that the module is transmitting a message on the
communications wire. However, it is not receiving a response from the addressed
Slave. This error is typically caused by one or more of the following conditions.
 Parameter mismatch, for example the module is set for 9600 baud, Slave is
set for 19,200, parity is set to none, Slave is expecting even, and so on.
 Wiring problem, for example the port jumper on the module is set incorrectly,
or + and - lines on RS485 are switched)
 The Slave device is not set to the correct address, for example the Master is
sending a command to Slave 1 and the Slave device is configured as device
10.
With a -11 error code, check all of the above parameters, wiring, and settings on
the Slave device. Also make sure that you cycle power to the module.
Error codes of 253 to 255 typically indicate noise on RS485 lines. Make sure that
you are using the proper RS485 cable, with termination resistors installed
properly on the line. If termination resistors are installed, try removing them as
they are usually only required on cable lengths of more than 1000 feet.
Command List Entry Errors
Code Description
-41 Invalid enable code
-42 Internal address > maximum address
-43 Invalid node address (< 0 or > 255)
-44 Count parameter set to 0
-45 Invalid function code
-46 Invalid swap code
The above error codes indicate that the module has detected an error when
parsing the command.
For all commands that have not been configured (all parameters set to a value of
0) you will receive an error code of -44. To remove this error code, you can
change your C
OMMAND C OUNT parameter to the number of commands that are
actually configured and cycle power to the module to transfer the new values.