Genius plus communications CMM302

I have two GE 90-30 PLC'S connected together with with cmm 302 communications cards. The problem I am experiencing is that setting a bit true in one plc results in the corresponding bit in the other plc becoming true and then toggling off and on continuously. The same is true for either plc. There is nothing else over writing these bits. The only way I have found to correct this is to set the Parameter ''Data Default'' in the 302 card to Hold. Only then do the communicated bits behave as expected. Does any one have any ides?

Why don't you post the configuration settings for both CMM302 modules. That would include Genius Serial Bus Addresses and the global data addresses and size values. Are there any other devices on the Genius bus?

Has the system ever worked properly?

Cmm302 Settings

The Settings are:
Serial Bus address 1
Data Rate 153.6
Device Type controller
Drop id 33
Data Default hold
Report Faults no

Serial Bus Address(sba) Reference Address Length
1 %R2000 5
5 %R1200 5
This is a new build, and I am trying to set this up in the shop
Regards

1) Are you writing to this bit from both directions? Can you disable your logic on one end to see if this "fixes" it?

2) Latches or coils? Latches would probably be better...