Analogue Output Values

Good Day Gents....New here

Does anyone know if using a SLC500 and a 1746-NO4I you can associate the output value directly with the integer value without moving the integer value to the output with a MOV function.

welcome to the forum ...

personally I'm not sure what you're asking here ... the word "associate" doesn't come up that often ...

just a guess ...

IF (big IF) you're talking about the "OUTPUT" of a PID instruction, then the answer is "no" ...

the reason is that the PID puts out a value which ranges from 0 to 16383 ... the module that you're asking about requires a value which ranges from 6242 to 31208 ...

(again, I'm just "guessing" as to what you're asking) ... so ... you can't just "move" the value from the PID to the output address - and you can't just enter the module's output address as the CV (Control Variable "output") of your PID instruction either ...

if my guess is correct, you probably would be interested in using an SCP instruction ... that beast can "scale" the PID's output value appropriately – AND – also "move" the scaled value to the output module's destination address at the same time ...

Ron. The system I am working on uses three analogue outputs to provide 4-20mA to three VSD's. In the program I can find SCP scale blocks to provide values based 0-100 engineering units for 6242-31208 raw values for the three units, but only one of these values is copied to an output e.g N10:20 is copied to O:8.0 The other values do not seem to be copied or moved anywhere in the program. My question is can you directly relate a value in N10:21 to O:8.1 without using a COP or MOV block. Hope this makes it a bit clearer

Regards Graeme

If you are asking about aliasing, then no, not on the SLC series. You must move values around with the standard instructions.

Are you sure that the COP isn't copying all three values at the same time? (i.e. COP #N10:20 #O:8.0 3)

another guess – based on the following:

but only one of these values is copied to an output e.g N10:20 is copied to O:8.0

Click to expand...

suppose that the instruction being used for this is a COP (Copy) instruction – and suppose that it has the Length specified as "3" ...

in that case, the COP is also moving N10:21 to O:8.1 – AND – it's also moving N10:22 to O:8.2 ...

if this isn't your answer, then I highly recommend that you post your RSS file and let us help you nail this down ... (you'll have to ZIP the file first) ...

PS EDIT ...

looks like cbuysse has the same idea ...

Thanks Gents....Thats the answer. The length in the copy block is set to '4'. I had not used this block before so was unfamiliar with its function. Thanks to you all

Regards Graeme