R in PLC

[damaged 0]

I ran across an R value or an address today, can anyone tell me what this is and what it means?

[navillusi 2]

"R" is a file register used with the Q series CPU, 16 bit data word, up to 1018k points depending upon size of processor and memory card

[Colin Carpenter 10]

It's also used with the older An series and the QnA and the FX2N series of PLCs. As I understand it, (might be wrong), File Registers are a bit different from other registers in that they are the stored in a seperate area of memory from other variables. To enable File Registers, you need to lose some programme area memory. For example, in the FX2N, you lose 1000 steps of memory to enable 1000 File registers. They are battery backed and reckoned to be vary safe from data loss...... though I can't really explain why.

[damaged 0]

Colin, Yes it is an A series PLC and a 870 series GOT writing the value and the value holds if the power is cut off. Thanks for this information. How can I find this in GX D?

[waynes 8]

Have a look under the parameters, "memory capacity" tab. You can set the file registers in blocks 0-8. 1 thousand points will use 2048 bytes.