adccommunitymod (AutomationDirect) asked a question.
Created Date: October 17,2013
Created By: HCS Plating
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Long and short of the issue is that I have an analog Click plc and have a program that ramps the output voltage up to a setpoint. The output is sent to the control board of a DC power supply that outputs 0-9VDC to the system bus. I have the 0-5 and 0-9 plugged into my scaling function however I end up with some compounding error as the output increases. attached is a pdf showing the actual voltage vs the input voltage at my HMU as well as the delta between the two. My question is should I try to correct this using the built in scaling or do I need to write some code to overcome this? Any recommendations would be greatly appreciated. Thanks Chris.
Created Date: October 17,2013
Created by: bcarlton
Do you have reading of the actual analog output - 0 to 5 volts - for each point?
Is the error in the DC Power Supply and you are trying to get around it?
Created Date: October 18,2013
Created by: HCS Plating
bcarlton, thanks for your reply. I did not think to check the output of the analog module so no I do not have those readings. I'm honestly not sure what the issue is with. the control is typically a potentiometer that is used in line with the vreff 0-5vdc signal. this is for manual control and an operator will adjust it by watching the analog gauge. I wish the analog plc had a 0-10 Vdc analog input as I could monitor the actual bus voltage and correct.
Created Date: October 18,2013
Created by: bcarlton
Can you provide a link to a manual for the power supply? And maybe a wiring diagram showing how you attached the analog output to the drive?
Created Date: October 20,2013
Created by: Herman
I wish the analog plc had a 0-10 Vdc analog input as I could monitor the actual bus voltage and correct.
With two identical resistors in series between bus and 0VDC, put the voltage between the resistors on your 0-5V input. Scale to get your bus voltage.
Created Date: October 22,2013
Created by: HCS Plating
Can you provide a link to a manual for the power supply? And maybe a wiring diagram showing how you attached the analog output to the drive?
Sorry for the delay. Thanks for stopping by. Attached are two schematics, one of the control portion of the power supply (unmodified), and a quick paint brushing of how i am connected. The relay at the bottom is there to switch between manual (potentiometer) control and the click "auto " control. The relay is triggered by the Y01 output of the click.
Created Date: October 22,2013
Created by: HCS Plating
unmodified
Created Date: October 22,2013
Created by: HCS Plating
modified circuit
Created Date: October 22,2013
Created by: HCS Plating
With two identical resistors in series between bus and 0VDC, put the voltage between the resistors on your 0-5V input. Scale to get your bus voltage.
Ahhh voltage drop... such an elementary solution to the feedback problem. Thank you sir.
Created Date: October 17,2013
Created by: HCS Plating
Long and short of the issue is that I have an analog Click plc and have a program that ramps the output voltage up to a setpoint. The output is sent to the control board of a DC power supply that outputs 0-9VDC to the system bus. I have the 0-5 and 0-9 plugged into my scaling function however I end up with some compounding error as the output increases. attached is a pdf showing the actual voltage vs the input voltage at my HMU as well as the delta between the two.
My question is should I try to correct this using the built in scaling or do I need to write some code to overcome this? Any recommendations would be greatly appreciated.
Thanks Chris.