Position Compare / Capture

[bmartins]

Hi,

 

I am using a PowerBrick LV to control four stages in a Coordinate System. I would like to setup Position Compare on the first stage and, every time that it triggers, have the position of the other three captured.

 

I guess I could wire the Equ output of the first stage into a user flag that the other three would Capture on, but is there a way to programmatically do that? If it's only possible to do that in CaptCompISR, what would be the typical latency and the jitter?

 

Thanks!

 

Bruno

[steve.milici]

The ServoCapt or PhaseCapt registers are only updated on the Phase or Servo clock respectively. This would be the “typical latency and the jitter”. Once the rate of compare passes this there will be no update on successive compares until the next Phase or Servo clock.

 

As you have surmised, you should use the hardware capture feature by bringing the EQU into the channels capture flag. The EQU is buffered with a 75451 which should have sufficient drive if the flag return is kept at digital ground.