Interference from VFD Off to 4-20mA analog signal loop drive Actuator

[Ingenieur]

The
board is having output that would need to be calibrated to the PLC display or the current input mA. I did calibrate this before. After sometimes, the output drifted up or drifter down

eg Input 40% Output 70%

what determines the 70% output?
manually set or automatic/software?
does it go to 70 when the pump is started?
and some control scheme uses the feedback to keep it there?

first thing
adjust feedback pot or software to match output
then set a filter on the input via the channel parameters

so when you drive the valve to 70% the fb matches?
then the fb drifts to 40?
but valve stays at 70?
is the fb pot loose on the shaft?

 

[Bmw318be]

Hi

Hi

Yes did, it worked perfectly, only when using the analog on scada at the site then the issue arise

what determines the 70% output?
Ans: The output was determined by the optical encoder with the gear reducer on the actuator [Attached]
manually set or automatic/software?
Ans: Both mechanical and software, the optical encoder could be recalibrate depending on the actuator mechanism. The principle of this actuator, at 100% there is a limit mechanism where the motor is unable to rotate (Rotating Counterclockwise),
at 0% is also there is a limit mechanism where motor is unable to rotate (Rotating Clockwise)
From 100% to 0% is 24 turns

does it go to 70 when the pump is started?
Ans: It does not, when it started, it just followed the last position of the input signal, however the output are out of range despite done synchronization

and some control scheme uses the feedback to keep it there?

first thing
adjust feedback pot or software to match output
Ans: Yes when calibration is done 0% input is equal to 4mA, 100% equal to 20mA, the output from the board was calibrated at 4mA and 20mA with the input. Somehow after calibration, the position error happened and the output does not match with the input.


then set a filter on the input via the channel parameters
Ans: How this can be done, in the software of hardware ? We used scada unity X1

so when you drive the valve to 70% the fb matches?
then the fb drifts to 40?
but valve stays at 70?

Ans: When this happened, actual position of the actuator does not match the actual feedback

is the fb pot loose on the shaft?

Ans: yes possible too, as there is guard screw holding this as per [Attached]

In the area of the equipments, we experience high interference such as dry contact is having 40 V, not sure if this has caused the board to receive the interference and send wrong feedback.

[Attached]

https://ufile.io/0a7a4

 

[Bmw318be]

hi

hi

Hi,

Can help to comment