can you help us how calibrate LVDT's?

what frequency or voltage plays role? can this be verified during markvie loop checks without moving the valve

 

This is not a simple question, and it really depends on the types of devices the LVDTs are attached to.

If you want details about frequency and voltage of LVDT circuits (excitation and feedback), please have a look at GEH-6721, Vol. II. You will need to know which I/O configuration is being used for the LVDT circuit in question (for example, PSVO or PCAA).

As for loop-checking LVDTs, it is possible to do some rudimentary loop-checks. But, I would be very interested to know what you mean by "loop-checking" of LVDTs. What are you expecting to learn or verify or ascertain when you "loop-check" LVDTs.

 

LVDT's are configured in PSVO cards. what we did was we connected spare LVDTs to PSVO I/O pack and verified by moving the arm and verifying the voltage in RMS. but want to know about frequency like it is fixed?

another question is if we do not put data on EGD in markvie toolboxst, can DCS pull data via OPC DA and OPC AE which is running in cimplicity HMI

 

The LVDTs are configured in the PSVO IOPACKs (IOPACKs are not I/O cards; IOPACKs are mounted on I/O cards).

So, all you've really done is confirm wiring between the TSVC/PSVO and an LVDT, not even the LVDT that will eventually be in operation. You have done <b>NOTHING</b> to perform a loop-check of the LVDT circuit that will be used in the control of the unit. You took a spare LVDT, connected it to the TSVC, and watched the indication change as you moved the <b>core</b>. This is not a loop-check; not by any stretch of imagination.

All you've succeeded in doing is verifying that the TSVC circuits you connected the LVDT wiring to sre enabled and capable of exciting an LVDT and reading LVDT feedback. That is not a loop-check.

A loop-check, by definition, must include the field wiring between the control system and the field device, and the field device.

Temporarily connecting a device directly to a terminal board is not a loop-check.

<b>Did you read the information about LVDT circuits in GEH-6721, Vol. II, in the PSVO section?</b> It's quite clear there how the LVDTs are excited by the Mark VIe.

While very off-topic, I don't believe that data which is not on an EGD page can be recognized/read by an OPC element. You should confirm that with the turbine packager representative which is likely on site to assist with installation and commissioning.

 

thanks