Hardware position capture upon index pulse on different channel

[andyf]

I would like to capture position of Motor[1] running on Gate3[0].Chan[0] in hardware upon the presence of an index pulse on Gate3[0].Chan[1]. It seems the position capture settings on the channel only support doing this with flags (CaptFlagChan and CaptFlagSel). Is it possible to do what I want by setting Motor[1].CaptureMode=0 and changing Motor[1].pCaptFlag to point to Gate3[0].Chan[1].Status.a ?

[Richard Naddaf]

Yes, you can. You need to redirect Motor[].pEncCtrl, and Motor[].pCaptFlag

[andyf]

Thanks Richard. After reading more yesterday about the Motor[x] setup elements, I convinced myself those are only for the PMAC software servo to know where to read from hardware registers. But what I need is to configure the encoder gate hardware to latch position on chan[0] when index goes high on chan[1], and put the latched value in the h/w register chan[0].HomeCapt.a. I don't see a way to do this with the Gate3[].Chan[] setup elements.

[steve.milici]

The index is fixed to the channel. You could, however, wire the index for channel 1 into a flag for channel 0 (or for that matter to its index) but make sure you make the appropriate hardware settings for 5v flags.

[andyf]

Thanks Steve. Regarding the flag inputs, I see the manual calls for 5V-24V. Do you think these might work at TTL level, such as 3.3V?

[andyf]

Just to close this out, I did receive an answer directly via email from tech support as follows:

 

"Not at 3.3V but it would depend on the device. Some TTL drivers will output 5V with a 5V pullup resistor."