G320 encoder power supply

[rbcmetalwork]

I have a three axis system with G320s and I am unclear on the wiring of a separate 5VDC power supply for the encoders (if they draw more than 50mA).

For any given G320:

Are three things attached to terminal 6 of the G320? The wire from the encoder negative, the wire from the 5VDC power supply ground and one end of the 470 ohm resistor?

Are three things attached to terminal 7 of the G320? The wire from the encoder positive, the wire from the 5VDC power supply positive and the other end of the 470 ohm resistor?

Can a single 5VDC power supply, with adequate current, be used for powering all three encoders (One output going to three places)?

What wattage should the 470 ohm resistor be?

Randy
Honolulu, Hawaii

[H.O]

Hi,
I don't have any G320's so I hope I'm not too far off here but here's how I see it.

Originally Posted by rbcmetalwork For any given G320: Are three things attached to terminal 6 of the G320? The wire from the encoder negative, the wire from the 5VDC power supply ground and one end of the 470 ohm resistor?

Yes, that is correct. The resistor is there to "fool" the drive thinking it is supplying current to an encoder. I believe it's needed for the internal voltage regulator to work properly. The ground for the encoder and ground from the powersupply gives the encoder and G320 a common reference for the A and B signals.

Originally Posted by rbcmetalwork Are three things attached to terminal 7 of the G320? The wire from the encoder positive, the wire from the 5VDC power supply positive and the other end of the 470 ohm resistor?

NO. Only the other end of the 470 ohm resistor. This terminal is the +5V "output" so you shouldn't connect the external +5V powersupply to it. Connect the external +5V to your encoders positive wire only.

Originally Posted by rbcmetalwork Can a single 5VDC power supply, with adequate current, be used for powering all three encoders (One output going to three places)?

Yes, that shouldn't be any problem. Wire the +5V from you external powersupply to the postive lead of all three encoders but not to any connection on any of the drives.

What wattage should the 470 ohm resistor be?

Since the voltage across the 470ohm resistor is 5V the current thru it is ~11mA so the power is developed in it is ~0.05W. A 1/4W or 1/8W resistor is more than enough.

HTH
/Henrik.

[Adamj12b]

I have a setup like this on my knee mill. I talked to Mariss when I was setting up my system. He told me that I needed a separate supply for each drive. IDK why, but thats what I did. Also, I have to look into this tomorrow, but I only have one common ground for the logic, I believe. I cant remember exactly right now though.

-Adam