Accuracy in Reading Pressure

[sandip B patel]

Dear Sir

I am using unistream  PLC  with analogue module wbc1 and i am reading 4 - 20 mA with respect to pressure 0 - 225 bar

but reading pressure is delay and pressure going overflow up to 10 bar

i set noice reduction is 50 hz

and sw sooming is none

so please suggest me  how to reduce is problem

waiting for reply

[sandip B patel]

reply sir

 

[Joe Tauser]

On 11/29/2019 at 6:23 AM, sandip B patel said:

but reading pressure is delay and pressure going overflow up to 10 bar

Please elaborate - if you monitor the pressure online it lags the actual pressure?

How can you tell and how much is it delayed?

Joe T.

[sandip B patel]

dear sair,

For Example , when i stop Pressure valve at 80 bar in manual mode ,the pressure in HMI is going up to 90 bar

and also in analogue pressure gauge

so please give the best solution for it.

[Joe Tauser]

So what you're saying is the process pressure keeps rising after you shut the valve.  Like its got a spring in it.

I don't think this is a PLC problem, as the HMI and the gauge agree.  If you observe the process when the valve closes, does the gauge say 80 or 90?

What's probably happening is you have some stored energy in the system somewhere in the form of an air bubble or the valve isn't closing quickly enough to clamp the pressure at the setpoint you want.  Without being there to look at it I can only guess.

If the overshoot is always 10 bar or it's predictably linear in some way, I'd modify the logic to shut the valve sooner based on actual observed (empirical) process data.

Joe T.

[sandip B patel]

Dear Sir 

thank for reply