Setting up a waterjet and running into walls.

About a month ago my boss where I'm doing my internship gave me permission to try to fix his waterjet with a broken motion controller. After asking around on reddit, I was adivised to go with a Mesa 5i25+7i77 pnp kit and run linuxCNC

I currently have the a computer running the software and about 80% of the wiring done for the Mesa cards. If I understand it correctly, I still need to ground the analog drives, wire 24v field power and correctly wire the limit/home switches to the 7i77 card. I've read these manuals a few times and been reading threads on the linuxCNC forums but I still have a few questions I havent found answers to.

For reference:

[Waterjet wiring diagram](drive.google.com/file/d/0B1kdAuhpoFaocnh...M3c/view?usp=sharing) Sheets 3 and 5 are the relevant diagrams right now.

[Pictures of the wiring cabinet](imgur.com/a/65oDV)

[7i77 card diagram](imgur.com/jDA7gi0)

[7i77 manual with pin descriptions starting on page 11 of pdf](www.mesanet.com/pdf/parallel/7i77man.pdf)

**Analog Dive interface.**(TB5 on 7i77 card diagram)



I've wired into the AOUT0 and AOUT1 to drive the x and y axis but I've not grounded them yet. I've found the ground wires for the drives in the wiring cabinet and they were both screwed into the same ground terminal and BOTH labeled pin 4. On Sheet 5 rungs 13 and 34 you can see x and y drives are grounded to pins 3 and 4 respectively. This leads me to believe that it doesn't matter which ground wire I screw into the 7i77 analog drive gnd for 0 and 1 (pins 3 and 7 on TB5 of the 7i77) as long as they both are grounded. Also, on the diagram it notes "DO NOT TIE (SIG GND) COM OF THE +/- 15VDC SUPPLY TO GND, UNLESS OPTO ISOLATION IS NOT REQUIRE). Not really sure precisely what this means and if I'm in danger of conflicting with it.

Also, for the Analog drive interface, each drive has 4 pins. (See 7i77 manual with pin.. page 15 of pdf) The first two are ENA0- and ENA0+. I assume these are used to enable the drives but I don't understand where wires that normally go to the servo drivers should be attached here.

I suppose the other possibility is that the enable pins are sent to 308CR (Sheet 3 rung 8 @ Waterjet wiring diagram) but I'm not really sure how I should try to accomplish that. I read in the yaskawa servo drive manual that these shouldn't be powered up and down frequently but I don't see how I can avoid it since it appears that the drive ENA -/+ should be wired to the one single relay that supplies power to the system.

Or am I mistaken and what's actually happening is that the CRM (Sheet 3 rung 15) sends power to the servo drivers and then 308CR simply enables them via the ENA -/+ pins from the 7i77?

**Limit Switches**



Luckily, it looks like finding the wiring for the limit/home switches will be super easy since it's already labeled in the cabinet and clearly marked on what used to be a 60 pin ribbon cable. However when I go through the pncconf for linuxCNC, I'm not really sure how to set those.

When I select my components (which I'm still not really sure if I'm doing correctly) I see 2 I/O tabs and 2 smart serial port tabs. In each tab I see a bunch of different drop down menus where I can select an axis limit but I'm not really sure how my selection there translates into which pin I need to wire to. I obviously see pin numbers beside each menu but how do I know which TB those signals are being sent to? I'm reading through the pncconf write up and it doesn't really mention this. I've also watched a few videos about going through the pncconf but they were for stepper motors so I'm not sure what does and doesn't apply. I think this is such a obvious answer that they never thought it would need to be explained but here we are...

**PWM**



On the first part of setting up my configuration, the menu box for setting up pwm base period is grey. Also, it doesn't allow me the option to select a number of pwm in the same way I can select '3 encoders'. I'm not sure if this is normal, I need to make another selection or if I didn't locate the 7i77 firmware files correctly in the directory.

In the same way I'm unsure of how to designate limit switches and their corresponding pins, I'm not really sure under which tab and which pin I should be selecting PWM for a given axis. Right now, my analog drives are wired into TB5 drives 0 (x axis) and 1 (y axis).

Random question but why are there so many field power inputs? From page 6 of the 7i77 manual, it says pins 1-4 are for 8-32v field power. I'm just curious why there needs to be more than one? Is that to accommodate higher load conditions?

**PID control**



For the 'base' tune, should I just go with the default settings and then change it after I see what it does to the servos? Also, to avoid a catastrophic crash, I should probably disconnect the servos from the ball screws. Is there anything I should know before I do this? It seems like it's just a matter of unbolting them from their position and letting them rest there disconnected but I don't want to overlook anything there.

**Encoder resolution**



In the 'pncconf step by step guide' it seems like it's telling me to to basically throw some numbers in there and then through trial and error of how much the machine actually moves vs how much I tell it to, determine the resolution of the encoder. Is this really the way it's done?

I've wired into the AOUT0 and AOUT1 to drive the x and y axis but I've not grounded them yet. I've found the ground wires for the drives in the wiring cabinet and they were both screwed into the same ground terminal and BOTH labeled pin 4. On Sheet 5 rungs 13 and 34 you can see x and y drives are grounded to pins 3 and 4 respectively. This leads me to believe that it doesn't matter which ground wire I screw into the 7i77 analog drive gnd for 0 and 1 (pins 3 and 7 on TB5 of the 7i77) as long as they both are grounded. Also, on the diagram it notes "DO NOT TIE (SIG GND) COM OF THE +/- 15VDC SUPPLY TO GND, UNLESS OPTO ISOLATION IS NOT REQUIRE). Not really sure precisely what this means and if I'm in danger of conflicting with it.

I would wire the analog inputs same as they were before that is Yaskawa V-Ref ( pin 3 ) to 7I77 AOUT(N) Yaskawa V-Ref SG ( pin 4 ) to 7I77 GND
(the pin adjacent to the AOUT(N) pin)

DO NOT ground the V-REG SG pins anywhere else but the pin adjacent to the corresponding AOUT(N) pin on the 7I77

Also, for the Analog drive interface, each drive has 4 pins. (See 7i77 manual with pin.. page 15 of pdf) The first two are ENA0- and ENA0+. I assume these are used to enable the drives but I don't understand where wires that normally go to the servo drivers should be attached here.

I suppose the other possibility is that the enable pins are sent to 308CR (Sheet 3 rung 8 @ Waterjet wiring diagram) but I'm not really sure how I should try to accomplish that. I read in the yaskawa servo drive manual that these shouldn't be powered up and down frequently but I don't see how I can avoid it since it appears that the drive ENA -/+ should be wired to the one single relay that supplies power to the system.

Or am I mistaken and what's actually happening is that the CRM (Sheet 3 rung 15) sends power to the servo drivers and then 308CR simply enables them via the ENA -/+ pins from the 7i77?

I would leave CR308 for Estop

The drive enables ( ENA(N)- and ENA(N)+ ) should be wired to the Yaskawa servo S-ON pin if I understand S-ON correctly

ENA(N)+ to S-ON (Yaskawa pin 14) and ENA(N)- to Yaskawa pin 35

On the first part of setting up my configuration, the menu box for setting up pwm base period is grey. Also, it doesn't allow me the option to select a number of pwm in the same way I can select '3 encoders'. I'm not sure if this is normal, I need to make another selection or if I didn't locate the 7i77 firmware files correctly in the directory.

In the same way I'm unsure of how to designate limit switches and their corresponding pins, I'm not really sure under which tab and which pin I should be selecting PWM for a given axis. Right now, my analog drives are wired into TB5 drives 0 (x axis) and 1 (y axis).

Not sure about pncconf but you can always look at the created hal file to verify which I/O pins are wired to what signals

Random question but why are there so many field power inputs? From page 6 of the 7i77 manual, it says pins 1-4 are for 8-32v field power. I'm just curious why there needs to be more than one? Is that to accommodate higher load conditions?

The 7I77 field outputs can draw more than 6A for short periods so more than one power connection is required

**PID control**



For the 'base' tune, should I just go with the default settings and then change it after I see what it does to the servos? Also, to avoid a catastrophic crash, I should probably disconnect the servos from the ball screws. Is there anything I should know before I do this? It seems like it's just a matter of unbolting them from their position and letting them rest there disconnected but I don't want to overlook anything there.

Definitely disconnect the linear axis if you have not tuned a servo system before, as run-aways are _expected_

**Encoder resolution**



In the 'pncconf step by step guide' it seems like it's telling me to to basically throw some numbers in there and then through trial and error of how much the machine actually moves vs how much I tell it to, determine the resolution of the encoder. Is this really the way it's done?

No, encoder resolution (or in your case drive quadrature output resolution) is simply counts per machine unit

( where machine units are inches or mm ) You would only need to determine this empirically if you had no
machine documentation