Despatch Protocol Plus Modbus Communications User Manual
Page 37
Chromalox Instruments and Controls
A-51643 Rev. 6 10/06/03
31
addressed to the slave are monitored, but no action is taken and no responses sent. The Restart
Communications Option function is the only command that will bring the slave out of Listen Only Mode.
Example: Force slave device 23 into Listen Only Mode.
Query
No Response
Field Name
Data
Slave address
$17
Function
$08
Sub-function hi
$00
Sub-function lo
$04
Data hi
$00
Data lo
$00
CRC
$----
5.3.1.5 [08 10] Clear Communication Counters
Clears all communication diagnostic counters. Counters are also cleared upon a controller reset.
Example: Clear communication counters in slave device 23.
Query
Response
Field Name
Data
Field Name
Data
Slave address
$17
Slave address
$17
Function
$08
Function
$08
Sub-function hi
$00
Sub-function hi
$00
Sub-function lo
$0A
Sub-function lo
$0A
Data hi
$00
Data hi
$00
Data lo
$00
Data lo
$00
CRC
$----
CRC
$----
5.3.1.6 [08 12] Return Bus Communication Error Count
The response data field returns the quantity of CRC errors encountered by the slave since its last reset or
clear counters command.
Example: Return bus communication error count in slave device 9.