Hello,
[quote='curtwilson' pid='476' dateline='1277395128']
So in the PMAC2 ASICs, we used a level-triggered capture. In this case, if you are in the trigger state when you start such a move, it will trigger immediately.
[/quote]
And this is the problem in my case: I have to measure the time between two external pulses (between index pulse of one axis and an external trigger) to synchronise the axis to the external event. Due to high precision requirements (~0.01°) it is not useful to capture just any time at the high level of the pulse.
Right now I use a relative complicated plc to check the actual state of the pulse and to make sure afterwards, that the activating of the capturing does always take place at the low level.
It works, but it is relatively slow. The order of the pulses is undetermined, so I have to wait a lot for the right state. This would be done with a real edge triggered capturing.
Is there an easier way to measure the time distance between two external input pulses? I thought about using the MLDT-measurement, but this always started by the internal clock, so I would have to use two of these inputs and calculate. - I have just two standard ACC24E channels per axis, one is used for the common encoder, the other one measures the time as an up counter with 2MHz clock (external) and several capture inputs.
Any hint is welcome -
Dirk