Configuring 4-20mA Analog Output signal

 Sorry. Maybe you also need to use NORM X instruction. But before connecting to the VFD I would recommend to measure the output with different values. If the scale X function alone can't produce the desired output, you must use NORM X instruction. Again sorry for not clarifying it clearly, because I am not in office now. There are lot of threads here for this. But self test is the best. Try to measure the values before connecting to the real input.

Thanks,

Jay

Jay.

 It should work. You can use a clamp meter to measure the output current and you can aslo change the percentage and see the change in current. So that you get a clear idea about the output from the PLC.

Thanks,

Jay

rzuhair

So, I did this. Converted the 0-100% signal from PID Loop to a signal of 5529.6-27648.0 [4-20mA]. When I move it to %QW it changes to 16#159A. Please let me know if it will work.

 

0 mA = 0 (decimal) = 16#0 (hex)
4 mA = 5530 (decimal) = 16#159A (hex)
20 mA = 27648 (decimal) = 16#6C00 (hex)

 Huggy,

Actually we are using a Wago AO module. So, it's resolution is 0-32767. I have the code working now. Actually, the output tag was of the Data type word, so even if was writing an "Int" value to it, it was being written as a "Word" in Hex format 16#. I changed the data type to Int and it is perfect now. Plus, another issue was the module itself. It needs two power signals a + and a - in addition to the 24V bus supply. Re arranged the rack and it's all good.

huggy_d1

If your analog output module supports 4-20mA, the 4mA = 0 at the QW address, with 0-100% scaling 0 to 27648.

If your analog output only supports 0-20mA, the 4mA = 5530, and 0 - 100% scales 5530 to 27648.

Is that at all what you are asking?

Does your VFD or PID Controller accept 4-20mA?

ixo65

0 mA = 0 (decimal) = 16#0 (hex)
4 mA = 5530 (decimal) = 16#159A (hex)
20 mA = 27648 (decimal) = 16#6C00 (hex)

 

New question published by ZINOU998877 is split to a separate thread with the subject SCALE_X for outpout programming.

Best regards
Jen_Moderator