During Mark 6 servo valve calibration, what is meant by servo current verification?

Thanks in advance.

 

This topic has been covered several times in various threads on control.com. Two good posts on the topic are:

http://control.com/thread/1026214897#1026214962

http://control.com/thread/1026231450#1026236852

I tend to make a distinction that the servo-valve is not calibrated, but rather the feedback from the LVDT(s) is(are) calibrated. But, it's very critical when performing LVDT calibrations, or when replacing servo-valves to make sure the polarity of the current being applied to each of the servo-valve's coils is correct, or, the unit can be tripped while running when re-booting a single processor or if a single processor fails!

Incorrect servo-valve polarity can also cause nuisance and intermittent "problems" which usually results in replacement of the servo-valve (unnecessarily) and does *NOT* require recalibration of the LVDT(s). (That's right: replacing a servo-valve does *NOT* require calibrating LVDT feedback!)

While the threads above are related to Mark V, the servo-valves used are exactly the same regardless of the vintage of the Speedtronic.

If the Speedtronic panel is a SIMPLEX panel, the servo-valve should have two coils and it's still just as important to check the polarity of both coils independently of each other.

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CSA,
Thanks a lot.
Your usual co-operation is highly appreciated.