Following error randomly missing

[Xtof]

Hello

I am using CVI 8 and NI Motion 7.4 with a stepper motor (closed loop with an optical coder) controlled by a 7358 board (there are up to 6 motor drives running at the same time but I had the same problem without parallelizing the operations).

Here is what might happen sometimes : the axis is mecanically blocked so a following error is detected, and the axis is killed. This is perfectly fine. Now, sometimes, when I use the function "flex_read_axis_status_rtn" to get the status of the following error bit, it is off... Does anyone have a clue why a following error would be missed while the axis was still properly killed?
This does not happen frequently but I have seen this several times already, and it it quite important for me to solve this because my test could pass successfully although the product under test might be defect.

Thank you for your help

Christophe

[Xtof]

Hello!

I still have my problem, but it might be slightly different from what I described above (although the result is the same for me), so here is a description of what I do :
1) I get the current position
2) I set the target to this position minus 3 rotations (the motor should be mecanically blocked after only one rotation)
3) I check if the move is complete
4) I check if there was a following error (the following error parameter is set to less than 5% of one rotation)

The change between my previous tests and the latest ones is that I know there is no more "unwanted" mechanical block. Bus still sometimes, the motor turns only a few steps (or not at all sometimes), and stops (but the axis is not killed) without any followwing error, as if the destination was reached properly.

I also tried to change the board (we have two running), but I still have the same problem with the other one.

Any clue, someone?

Thanks for your help

Christophe