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Table 6-10. error code bytes for pcs modbus slave – Micromod Micro-DCI: 53MC5000 PLC AND PRINTER INTERFACES User Manual

Page 81

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Table 6-10. Error Code Bytes for PCS Modbus Slave

Title

Definition

DDI-A DDI-B

Set

By

De-

fault

Exception Response
Code*

Exception Response Codes 1-3 are sent
from the PCS slave to the Modbus
master.
01 - Illegal Function: Does not exist as a
valid function code.
02 - Illegal Data Address: Not an allow-
able address for the specified slave
location (L address over L2047 or C
address over C767).
03 - Illegal Data Value: The data value is
not allowable in the slave (the fetch
quantity requested of a PCS slave
exceeded 512 L-values or 64
C- values).

B671

B647

Soft-
ware

0

Communications
Error*

0 = no errors. 254 = bad checksum
(CRC) - a bad checksum indicates even
though the frame was formatted
properly, the data can not be used. 253
= bad message - bad message indicates
that errors were found in the predictable
portion of the message from the master
device. 252 and 251 = PCS hardware
malfunction.

B672

B648

Soft-
ware

0

Error Count*

This byte is a running total of the
Exception Response Codes and the
Communication Errors listed above.

B673

B649

Soft-
ware

0

*User can reset by writing zeros into the datapoints.

Section 6. MODBUS RTU Mode

MODBUS2

6-17