Carrier RTU Open v3 Integration Manual

Contents

Communications wiringRTU Open v3 Carrier Proprietary and Confidential CARRIER CORPORATION ©2016Integration Guide All rights reserved11Wire specifications○ A dedicated 22 AWG shielded twisted pair wire (EIA 485)○ Maximum wire length 2000 feet (610 meters) or 32 nodes○ Devices should be daisy-chained and not star-wired○ Attach the drain/shield wire to both ends of the network segment and through every controllerNOTE Use the same polarity throughout the network segment.7 Turn on the RTU Open's power.Troubleshooting ModbusCheck the following to troubleshoot your RTU Open:1 Verify that the BAS and controller are both set to speak the Modbus RTU protocol on the Comm Selector DIPswitches DS3 - DS6.2 Verify that the BAS and the controller are both set for the same baud rate:○ Baud rate DIP switches DS2 and DS1○ Obtain a Modstat of the controller. Scroll to the bottom of the page to Network Communications to viewthe 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 configurejumper 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 1stop 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 (page 35) for the Network Points list.• Refer to Appendix C (page 47) for the Protocol Implementation Conformance Statement.Modbus Exception Codes that might be returned from this controllerCodes Name Description01 Illegal Function The Modbus function code used in the query is notsupported by the controller.02 Illegal DataAddressThe register address used in the query is not supportedby the controller.04 Slave DeviceFailureThe Modbus Master has attempted to write to a non-existent register or a read-only register in thecontroller.