Controllogix 1756-PLS resolver simulation?

colemanj

Member
Join Date
May 2010
Location
Alabama
Posts
3
I have a 3-slot Controllogix 1756-PLS module. I need a way to ocasionally allow technicians to "disconnect" the resolver (using a touchscreen button and simulate the rotation of the machinery using ramp buttons (clockwise and counterclockwise) on a PanelView Plus screen.

I can manually inhibit the module and write to the "Position" value from the PanelView. This allows the machinery graphic to rotate on screen as if the resolver were actually turning. But inhibiting the module also inhibits the I/O cards attached to it. I need the outputs to continue working.

Is there any way to inhibit just the resolver but keep the module's I/O functioning? Any workarounds?

Thanks.
 
Don't inhibit the module.
Copy the position value to a tag. The copy is conditionally enabled/disabled.
Allow the user to write to the tag. If the execution condition is true, then the resolver writes to the tag, inverse & the PV can write to the tag.
 
A number of methods spring to mind depending on what you really are trying to achieve
1) Use the module Nudge Zero inputs to change the Zero offset on the resolver
Up and Down When you are "Rotating" the the resolver (Reset the offset with a Offset MSG before normal operation) (can use InputOverrideEnable and Value to program input bits 30 and 31 from the PLC to control the nudge)
2) If the purpose of the "rotate" is to test the outputs of the PLS then just overwrite the outputs using OutputOverrideEnable and OutputOverrideValue

Warning when I was last using this module (Ver 2.2/2.3) the CST timestamp did rollover correctly (Lower 16 bits was correct Upper 16 sometimes was out for a scan) I just worked around the problem and did not use CST so haven't checked the latest firmware
 

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