[EvanGtown]

A 1981 Wells Index 810 Series CNC Machine was donated to my high school. It was updated twice, once with a rs232 serial port and second with a sharnoa monitor and control panel.

The battery was left to die and all of the software was deleted and we cannot find the executive tape, and cycle tape.

We ordered three gecko drives in order update this machine. We are hoping that these will help us get this machine running. We plan on using the power supply built into the machine to power the servos and understand how to connect those to the gecko. We are struggling with the encoder wires. We have found that the servos have BEI encoders attached, Model - L25J-SB-1000-ABZ-7404-LED-FB-S. There are about 8 wires attached to the encoder, but from what we can tell only four wires that get attached to the Gecko (2 for power, 2 for info). We are at an impasse here. Does anyone have any suggestions? It looks like some other people have tried this, but we aren’t sure about these last few wires. Thanks for you help!

[jalessi]

Evan,

What are the colors of the wires?

Jeff...

[jalessi]

Evan,

See the attached image, it is a educated guess.

Jeff...

[EvanGtown]

Jeff,

Thank you. Shortly after your note, we received the spec sheet for our BEI Encoders, see attached. So, we have hooked up our encoder wires. We have a Green wire hooked up to the Channel A port on the Gecko & Channel A on the Encoder. We have a Red Wire Hooked up to Channel B port on the Gecko & Channel B on the Encoder. We have a Blue wire hooked up to the +5VDC on the Gecko and the V connection on the Encoder. There were 4 black wires coming from the encoder and according to the spec sheet they are all linked together, so we just picked one and attached it to the ENC ground. We also attached the Power source positive & negative to the first two ports on the Gecko.

According to the manual sent by Gecko, we should be able to test functionality at this point. We hooked everything up, and it says that the Fault indicator (Red LED) should come on and then quickly go off. The In Position indicator (Green LED) should then come on. The power indicator (Green LED) should always be on. Unfortunately, once we power-up the Red Light & Green Power light come on and both stay on.

Any ideas on what to do next?

Thanks!

[EvanGtown]

BEI Encoder Spec Sheet Attached FYI

[multiplex]

well i've never used either product

however, you might want to check the power requirements of the encoder verses what the gecko can output.

I've read of instances where the encoder requirements are too high

from the gecko manual

ENCODER HOOK-UP
The encoder must be a digital quadrature TTL output type that operates on a single +5VDC power supply. The power
supply current rating must be less than 50 mA. It should be at least a 200 line encoder. If the encoder supply current is
more than 50 mA, use an external +5VDC supply. IMPORTANT: Connect a 470 ohm resistor from TERM. 6 to TERM.
7 if an external power supply is used for the encoder.

from the Encoder manual

Current Requirements 200ma Max, 150 typ

[jalessi]

Evan,

I believe the current draw on your old encoders exceed what Gecko specifies.

You may want to call Gecko and confirm my guess.

AMT makes a very good and inexpensive encoder.

http://www.amtencoder.com/

Jeff...

[jalessi]

Evan,

Multiplex's suggestion is correct, I was typing and did not see his post.

Sorry for the redundant info.

Jeff...

[EvanGtown]

Thanks for the advice guys. I think the current output won't be a problem if we use an external power source capable of sending more current to the encoders. We did hook everything up, and now we are having some more issues.

Here is where we are. We have the gecko drive hooked up to the encoder, power source, external 5vdc power source and computer. We get the double green lights (power & in-position) as we should after power up. The number 5 & 7 Terminals are connected. When we press jog on the computer, the lights go from green (in-position), to yellow (Warn) to Red (Fault) as they should. Unfortunately we can only get the lights to move when we jog in one direction, they don’t repeat in the opposite direction.

When we attach the armature wires from the motor, things get a bit more interesting. We get the double green light when we apply between 13.5 -14 volts (which is too low for the gecko). When we go higher we get a green (power) and red (fault). At about 23-30 volts the motor starts to spin and we get a green (power) and either a flashing red (fault) or sometimes a yellow (warn). Nonetheless, we don’t understand why power is being sent to the motor without us pressing anything on our computer.

The gecko manual talks about a momentary “Start” switch. Is this something we would add? Should it be a switch between the #5 & #7 terminals? I have noticed that upon start up, if the #5 & #7 terminals are not linked, the red (fault) will be illuminated, but if I touch a jumper from #5 to #7 terminal for just a bit, the light will turn green (in position).

We feel like there is light at the end of the tunnel, but are at an impasse right now. Any ideas, or does this not make any sense at all?

Thanks!

[jalessi]

Terminals 5 and 7 should be connected in order to enable the drive.

Using the circuit described in the manual is a good idea.