5i25/7i76 to gecko201 wiring questions?

I am new to machining, know even less about CNC or Linux so please bear with the DUMB questions. I was hoping to have a nice little machine shop in my garage if/when I'm able to retire, so that I could do some gunsmithing. Now I'm thinking that I may have to make a "career" change due to back problems being aggrevated by my present job. So considering mfg AR parts, barrels, etc. as a possibility.

I bought an Enco mill several months ago that had been partially converted to cnc. The ball screws are partially installed on the X and Y axis and it had a cncmasters cnc kit. I am ditching my cncmasters kit for 5i25/7i76 so that I can run linux. Stripping the power supply and 201's from the cncmasters and starting over.

Printed the manual on the 201's and it seemed fairly straight forward. So I ordered the 5i25/7i76 kit from Mesa several months ago. Finally trying to figure it out, when I first looked at the pics on the site I figured each terminal block on the 7i76 would control each 201. Man was I wrong, finally figured out that TB2 controls 4 of the 5 axis. The manual shows each axis has 6 output pins, 1 GND, 2 STEP0-, 3 STEP0+, 4 DIR0-, 5 DIR0+, 6 +5VP, etc for each axis.

Pin 1 GND do I need to connect it? If so where? Is it 120AC GND, 5VDC-?

Pins 2/3 STEP0 +/- would connect to Terminal 9 on the Gecko 201? Seems strange that the + & - would both connect to the same pin. (Seems like a possible short somewhere to me?)

Pins 4/5 DIR0 +/- would connect to Terminal 8 on the Gecko 201? (Still seems like a possible short?)

Pin 6 +5VP would connect to Terminal 10?

Thanks in advance,
Ken

BigJohnT wrote:

Ken,

Have you seen this page it will help with the I/O wiring.

The 201 like the 203v needs 3 wires from the controller, 7i76 Direction - to 201 pin 8, 7i76 Step - to 201 pin 9, 7i76 Common + to 201 pin 10.

If we are still talking about the 201 terminals pin 1 goes to your DC 0v and pin 2 goes to your DC +.

I need to do a wiring diagram on my plasma one day...

John

John,

Had not seen that post, but did find this page before I read the manuals for the 201's and 5i25/7i76. They make a little more sense now, but still confused.

gnipsel.com/linuxcnc/configs/index.html

You said, "the 201 needs 3 wires from the 7i76. 7i76 direction to 201 pin 8." (There are 2 dir pins on the 7i76, pin 4 (-)& pin 5 (+)).

"7i76 step to 201 pin 9." (There are 2 step pins on the 7i76, pin 3 (+) & pin 2 (-)).

Concerning pin #1, I was actually refering to the GND on each axis of the 7i76 (pins 1, 7,13, &19 on TB2 connector)

Yes, pin #1 on the 201's, should be main DC 0V-, and pin #2 should be main DC+. It appears on the cncmasters that the large blue capacitor is wired in this leg. I have also read that they (each 201), should be wired in a "star" configuration rather that "series". Any thoughts on the capacitor, or "star" configuration?

I'll check the 5i25/7i76 to make sure that the "switches" are in the proper position to provide 5V DC.

thanks,
Ken

The 7I76 has differential step/dir outputs. What this means is the there are 2 pins for each step and dir signal. These pins are the + and - pins. These pins are driven with opposite polarities (when the - pin is low the + pin is high and vice-versa)

Some drives can accept + and - inputs and benefit by using both pins by being less susceptible to noise.

The Gecko drives do not used differential signals but rather have single ended inputs so will only use one of the + or - signals. The unused output of each pair should be left unconnected. (tying them together would cause a short)

PCW wrote:

The 7I76 has differential step/dir outputs. What this means is the there are 2 pins for each step and dir signal. These pins are the + and - pins. These pins are driven with opposite polarities (when the - pin is low the + pin is high and vice-versa)

Some drives can accept + and - inputs and benefit by using both pins by being less susceptible to noise.

The Gecko drives do not used differential signals but rather have single ended inputs so will only use one of the + or - signals. The unused output of each pair should be left unconnected. (tying them together would cause a short)

PCW,

Thanks, that makes sense with high/low voltages. I thought that tying them together would create a short, that's why I was concerned about the directions in the manuals.

I guess I'll use the + on the step, and the + on dir, and leave both -'s empty.

thanks,
Ken

Just reread John's post, it looks like he may have said to use the - on the step and - on the direction. Wasn't sure if that was a voltage symbol, or punctuation.

I'll use the -'s and leave the +'s empty.

thanks,
Ken

Thanks John, OK negative it is on the step and dir.

Ken

Sorry, but everytime I think I've almost got this thing figured out, I run out of time and don't get it wired. Then I have to go back and figure most of it back out again. Maybe this time I'll "get 'er done".

OK, just reread this thread, so most of my questions already answered on wiring the 7I76.

Only 3 wires from the 7I76 for each axis. -step, - direction, and 5V+;

What about the GND on the 7I76, terminals # 1, 7, 13, and 19 on TB2 terminal strip? Should it connect to terminal #1 on the 201's, which appears to be common ground AC and DC.

Are there any input wires on the 7I76 other than the cable from the 5I25?

thanks,
Ken