when will we tuned the zero and span of i/p converter?

There are two instances of when to calibrate a device:

• When the calibration schedule says that it's due to calibration (you do have a schedule, right?)
• If you have reason to doubt that the unit is out of calibration

After you have calibrated the device, assuming you did it properly and the device is not defective, the unit should perform properly.

regards,

Vulcan

My bad...erratum

• When the calibration schedule says that it's due to calibration (you do have a schedule, right?) ... When the calibration schedule says that it's due for calibration (you do have a schedule, right?)
• If you have reason to doubt that the unit is out of calibration ... If you have reason to believe that the unit is out of calibration There's no grammar check button for the editor. regards, Vulcan

suppose some problem came in control valve at time of operation . i asked 4 maintence .

As I said, if you have reason to believe that the converter is defective (at anytime), you need to have it calibrated. If some problem came up during operation, then you have reason to believe that it is out of calibration.

I sense that this is going nowhere. Please provide complete information about your problem so that we can give complete answers. Don't be shy about giving details.

regards,

Vulcan

HI

Its necessary to tune the zero and i/p converter when there is defect in the control valve.

Also its necessary when the control valve is under maintenance.

Usually Control valve and i/p converter are calibrated based on the process disturbances.

Regards,

Zaki

Radicon Gulf Consult

KSA.

suppose some problem came in control valve at time of operation . i asked 4 maintence .

By "tune" I assume you mean calibrate (I know, ass/u/me ). The I/P should be calibrated prior to the calibration of the valve positioner. The calibration of the I/P may be checked periodically as your PM schedule dictates or as the valve performance comes into question.