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« on: November 03, 2017, 02:18:12 AM »
Hi,
that might sound like gobble-de-gook. Have a look at the attached pic.
This is of my Vexta stepper driver. The inputs (cw and ccw or alternately Step/Dir with the appropriate selector switches) are opto coupled.
At idle the driver requires that the opto be de-energised. If my BoB is naturally low at idle, ie high when active all well and good, the Bob and
the inputs are well matched and the upper diagram, ie current sourcing is used.
If however my BoB is logic high when idle it will cause the opto to be energised and consequently the first pulse will be masked. Either I need to add
some circuitry or more likely choose an appropriate hook-up to secure the result I want. That is the reason the manufacturer has provided for and published
the two alternatives current sourcing/current sinking. Vexta is a very good Japanese brand and has superb documentation.
Do you have documentation for the input circuit of your stepper drivers? How about a circuit of the output of your BoB? With both of those sorting your
problem will be easy, without it there will be some guessing and experimenting required.
Craig
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