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Axis position capture thru external trigger on a Geobrick
#1
I'm looking for an example or documentation the shows how to capture all axis position (counts) when an external trigger occurs. The external trigger will occur multipule times during a move at a regular interval as fast as every 2 milliseconds. The position data will be saved in a rotary buffer and extracted by the user software before buffer is full.

Any help will be greatly apperciated.

Thanks,
Islay
#2
Islay,

If you need exact position capture for all the axis at hardware level and at encoder sampling frequency, you can wire the trigger to user flag on all the axis and set up your I7mn2 and I7mn3 to capture the position on user flag high/low. Then you can have a PLC (possibly PLC0) to run and check the capture flag on status bit of the channels and if the capture has happened it would copy the captured position data from all axis to user buffer to be read by user software later. Just make sure the PLC0 is running faster than the rate the trigger is happening (I8 setting) and your PLC0 is written very efficiently so it won't take away too much time from background tasks.

Regards,
Sina Sattari
Hardware Engineering Manager
Delta Tau Data Systems, Inc.
#3
Sina,

Thanks for the quick response. I'm assuming that the captured position is stored in the position capture register
X:$07xx0x" pg 510 of Turbo Software reference manual. Is the position capture register only 24 bits wide?

Islay


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