limit and home switch set up

[tsdsib]

I have a Bridgeport series I cnc boss with 18 x 12 table. Software is Ajax M series v8.21
Ajax cnc7 controls. I am having a couple problems with getting the table to do what I want. The first problem is “find Home” X minus is selected, however the spindle/table travels in a “+” (plus) motion when “-“(minus) is selected. The x motor and table motion feel like they are fighting – not smooth travel. I checked the parameters, all looked fine.
Machine has a limit switch located at front/left for x and front/front for y. looking at the Jog parameters. This is what the installer had plugged in.
Travel (-) x: 0; y: 0; z:-4.800.
Travel (+) x: 16.000; y: 11.000; z: 0.100.
These are the Motor Parameters limit/home values were plugged in.
Limit x-: 0; y- : 0; z-: 12.
Limit x+: 0; y+: 0; z+: 0.
Home x-: 8; y- : 10; z-: 12.
Home x+: 0; y+: 0; z+: 11.
I read the Operators manual, Chapter 3-6. F1 - Travel Limits and Reference Return Points and Chapter 15.7 about limits and home switches. I tried different values for the motor parameters of x and y. z is fine, it finds home and hits the soft limit.
Does anyone have any experience with these problems.

[tsutt]

tsdsib, I think you have 2 options for changing dir of the motors. ! Is to reverse the power leads to the servos, 2 is to look at the pic of your screen shot and under the rev. heading change that to a y. And if your limits switches are working properly, push the switch by hand to test, Zero out the software limits that are on your screen. I've got switches on mine and never entered software limit's work perfect. when everything is going the right dir. do an autotune it will set it self. You may also have to change the homing program to home to the proper direction. Todd

[tsdsib]

thanks for the reply! the other day i did reverse the leads on the x and y servos and machine didn't like it - changed them back. i then changed the Dir Rev to "Y" for x and y and it jogs in the correct travel. i am going to check the limits tonight and try your advice. i will post what happens. thanks again.
kevin

[MarcL]

It sounds like your X limit switch is already tripped, or a wire has come loose.

If you ask the control to home, and the home switch already appears tripped, then the control goes immediately to the second step of homing: moving back in the other direction looking for the switch to clear.

Without attempting to home, can you jog X in both directions? Or just plus? Choose Slow, Continuous jog mode. That will probably only work if you have a jog pendant, though. I think keyboard jogging is locked out until the machine has been homed.

Press Alt-I for the PLC diagnostic display. Is the 8th dot on the top line (INP8) red or green? Does it change when you push on the limit switch?

If INP8 is red no matter what you do with the switch, then you have a bad contact or loose wire somewhere.

Good luck.

[tsdsib]

thanks for the advice from both. got the machine to do what i wanted. the advice for alt-I PLC screen was a huge help. did not come across this info in the manuals, might have missed it. now i understand the values in the Motor Parameters screen. i also spoke with Drew at ajax - i emailed ajax about my problems at he called me a short time later and then emailed me some information that helped too. thanks to all.
kevin