by cncdrive » Thu Jan 25, 2018 11:04 pm
What is your max.error parameter value?
The drive goes to alarm if the steps counts summary - encoder counts summary absolute value is greater than the max.error parameter value.
So, one possibility is that the max.error value is so low that when the drive powers up and tries to power the motor and so the shaft moves a little bit it immediately goes to fault before the loop could even stabilize.
The other possibility is that step signals are being sent to the drive, so when it is powering up and receiving these steps then the position error counter goes higher than the max.error parameter before the loop could even stabilize.
The third possibility is the same as the previous, but the drive getting encoder counts.
If you tried to replace the drive with another using the exact same motor same encoder and same cables and the other drive not producing this issue then the 2nd and 3rd possibility is out, but the 1st one is still possible, so verify the max. error parameter.
And there is one more possibility that the encoder interface IC got broken, overvoltaged etc. and so it is false counting causing the drive to think the encoder is rotating, however it is a 26LS32 line receiver chip in the drive which is a robust chip, it damages from high overvoltage only, above 25Volts difference on the input lines.
And one more idea which comes to my mind, but this applies only if the motor is actually rotating some when powering up is that you have the motor arm1 and arm2 reverse connected,
so the drive is moving the motor away from the setpoint when it should move it to the setpoint and vica versa. But for this issue I'm assuming that the motor is actually moving a bit when you poweing it up and if this is the case then you simply have to exchange the motor arm1 with arm2 connection.