Re: [CAD_CAM_EDM_DRO] Re: Servo motor keeps running. (urgent help required)

mina_aboulsaad wrote:

>Mariss,
>
>I did not connect the Encoder ground to the Gecko 320 Enc-, it went
>to the external supply -0VDC, while I connected a 670 ohm resistor
>from Enc- to Enc+ on the Gecko, should have I connected the encoder
>ground to the Gecko and only got the +5VDC line from the external
>power supply???
>I tried doing the test for the encoder mentioned in the G320
>installation notes, but the voltmeter kept reading 8.9 VDC, and
>wouldn't change while rotating motor shaft.
>
>

It really won't make much difference, the supply ground and enc- are
connected
together internally.

But, you may have a polarity problem. The motor wires and the encoder
signals
must have the same polarity for the servo to function. If the polarity is
backwards, the motor moves the wrong way to correct a position error,
making the problem worse. It should fault out after a short move, however.

The fact that it dosn't fault out, at least in some of the tests you
mentioned,
may indicate it is not getting proper signals from the encoder. You should
disconnect one motor wire so you can move the motor by hand, and then
check the encoder signals to be sure they go to roughly +5 V and ground
as you move the motor very slowly. Some encoders need "pull-up resistors"
on the signal wires. These would be resistors of about 1000 Ohms connected
between the A or B signal terminals and the enc+ terminal. If your A and B
signals stay near zero V all the time, you might try the pull up resistors.

Jon