DRO is driving me crazy.

[Anonymous]

Posted by Rik Shaw on 27/01/2016 18:27:12:

while chatting to a bod at WARCO, I mentioned the read out problem whilst ordering the new board. He told me that the speed controller should always be returned to zero position before both starting and stopping the mill (and the lathe as well). Mine is not to reason why so I have complied.

I recently bought the SPG version of the Warco and it mentions that at least twice in the user manual AND there was also an A5 sized laminated notice cable tied to the actual machine saying the same. Apparently they've decided stopping and starting at other than zero on the speed dial is the main cause of board failures.

[Martin KyteParticipant @martinkyte99762]

I'm not suggesting that you don't do as they say but having to return a speed controlller to zero in order to stop a motor sound to me like cheaply engineered electronics. I would expect 2 methods of stopping rotation. A normal stop button which would reduce the motors speed in a controlled fashion from the 'process variable speed' set by the speed control knob down to zero and then turn the drive outputs off. The second button should be the emergency stop which should immediately turn the output to the motor off. Normal use should use the first button.

Any machine with electronic speed control that only has the single way of stopping is to my mind a fudge and likely to cause issues with either the drive unit as suggested already and or mains spikes and radiated noise into other electronic systems local to the machine.

When I design anything if I don't want the operator to do something I ensure that the electronics wont let them.

regards Martin

[Rik ShawParticipant @rikshaw]

"I recently bought the SPG version of the Warco"

Thanks for that info Mick. You have confirmed my suspicions that in my case the replacement of three boards in less than three years could have been avoided had a caution plate been screwed to the front of the machines indicating correct start /stop procedure. An aside remark to this effect in the mill handbook is NOT enough. A component critical procedure such as this should be explained and emphasised in very large capitals – more than once !

Rik

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