Carrier RTU-MP, Integration Manual

Page: 27 / 58

RTU-MP Controller 23
Modbus
1
Verify that the BAS and controller are both set to speak the Modbus RTU protocol on the Comm Selector
DIP switches DS3 - DS6 .
Check the following to troubleshoot your RTU-MP:
2
Verify that the BAS and the controller are both set for the same baud rate:
○
Comm Selector DIP switches DS2 and DS1
○
By getting a Modstat of the controller through the BACview. Click and hold the FN key and then click
the . key at the same time. Scroll to the bottom of the page to the section entitled Network
Communications to view the active protocol and baud rate.
3
Verify that the BAS is configured to speak 2-wire EIA-485 to the controller. The BAS may have to
configure jumper or DIP switches on their end.
4
Verify that the BAS and the controller have the same communication settings (8 data bits, No Parity, and
1 stop bit).
5
Verify proper connection wiring between the BAS and the controller.
6
Verify that the rotary address switches are set for the controller's unique slave address.
7
BAS must be reading or writing to the proper point addresses on the controller.
8
BAS is sending requests to the proper slave address of the controller.
NOTES
• Refer to Appendix A for the points/properties list.
•
Refer to Appendix C for the Protocol Implementation Conformance Statement.
Modbus Exception Codes that might be returned from this controller
Codes Name
01
Description
Illegal Function The Modbus function code used in the query is not supported
by the controller.
02 Illegal Data
Address
The register address used in the query is not supported by the
controller.
04 Slave Device
Failure
The Modbus Master has attempted to write to a non-existent
register or a read-only register in the controller.
Johnson N2
Check the following to troubleshoot your RTU-MP:
1
Verify that the BAS and controller are both set to speak N2 protocol:
○
Comm Selector DIP switches DS3 - DS6
○
By getting a Modstat of the controller through the BACview. Click and hold the FN key and then click
the . key at the same time. Scroll to the bottom of the page to the section entitled Network
Communications to view the active protocol and baud rate.