Logix5000 data protection during external write

[cisco_kid]

Is there a way to prevent a block of data from being read by RSLinx while the data is being written too? I have a customer who is concerned that he will be reading data as it is being written and will retrieve incorrect data. I tried to get them to allow me to send an unsolicited ethernet message.. but they want to do it the old polling way. BTW, data is a 12 character barcode loaded into a DINT[6]. Customer is polling DINT[0], and asked me to write that register last, which makes it backwards from a simple COP command!

Thanks!

 

[Gerry]

You could try using the CPS instruction.
It should complete the copy operation without any interruption.

 

[Ken Roach]

That's a legitimate concern, and is one of the reasons the Copy Synchronous (CPS) instruction was added to the ControlLogix. CPS locks both the source and destination tags until it completes, so it takes a little more scantime. Just buffer your data into the tag that will be read using a CPS, and you'll be fine.