Hi All,

I have 2 1756-DHRIO/C 5.3 (Firmware) on a controllogix 1756 chassis; one at slot 5 and another on slot 6; both channel A & B of 2 RIO card are configured as RIO: 230.4k; cable length is less than 15m; Card 1; both channel connects to PV & 1756-FlexI/O; Card 2; both channel connects to Mettler-Toledo checkweigher ABRIO card; both card experience teh same MSG BTR problem.

I use MSG BTW/BTR to write/read data to/from the devices. At the beginning of setup, it works fine, but recently I found out MSG gets error and stop executing but DHRIO module doesn't show any error code. I need to uncheck the cache connection of the MSG for it to working as normal. Everytime when I try to check the cache connection, fault msg. "connection in use" appears.

One day I cycled power the PLC, the MSG can't execute, error msg. "connection failure", everything work fine after I check back the cache connection of the MSG...just after a week, the problem come back and I need to uncheck the cache connection again...

Only one BTR/BTW is executing at a time in the plc code. I also try to re-configure the unconected buffer to 40 (max.) but not help...

Need helps.

Thanks.