Actuated Valve

Hello,

On site, I have a fail open actuated ball valve that has been replaced. There is a 24VDC existing galvanic barrier supply on a 4-20mA scale, with a cable to the solenoid and a cable to the actuator for SCADA indication.

When installing this valve on site, it was wired up the same as the one that was removed, except I found that the valve would not stroke when commanded by the open selection on SCADA. I have checked the ladder logic and SCADA, and this all seems to be correct.

I checked the power on the supply cable whilst they were terminated in the solenoid and I only measured 6V DC. I then removed the cables and measured 24VDC.

I took the valve to the workshop and tested it there, it stroked at 20VDC+, but it seems when I connect it in the field it brings the power down to 6V DC, which is not enough to stroke the valve.

Any suggestions would be greatly appreciated.
 
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