limit switch

[grsabourin]

Hi,

I have issue with my limit switch/home position. When I do a homing of the machine, it never stop when the homing switch is pressed. If I look to the board (PMDX-122) the led come up when I press the switch but the machine does not stop. The only change I have done is to add a 1uF capacitor between each limit switch connection and the ground (JP5 on pmdx-122). I have also other issue with the probe. The probing operation told me that it is impossible to probe because the probe is already triggered. Surprising because the is on and come off when I push the probe (as normally). Is some one have any suggestion.

Thank you

[DaveCVI]

Hi,
This sounds like a ports & PIns configuration problem...

The Probe LED on the MSM pages should be off (grey) when the probe is not triggered. When you lightly push on the probe tip, the probe activates and the Probe LED should go on (green).

Since you said:

I have also other issue with the probe. The probing operation told me that it is impossible to probe because the probe is already triggered. Surprising because the is on and come off when I push the probe (as normally). Is some one have any suggestion.

Go to the mach ports & Pins dialog and check the setting for the Probe signal. It is probably set to "active low" - if so change it to "active high". That will reverse the logic of the probe input signal.

Hi,

I have issue with my limit switch/home position. When I do a homing of the machine, it never stop when the homing switch is pressed. If I look to the board (PMDX-122) the led come up when I press the switch but the machine does not stop. The only change I have done is to add a 1uF capacitor between each limit switch connection and the ground (JP5 on pmdx-122).

The LED on the break out board is showing you the voltage level of the limit input signal. Now check the logical mach signal for the limit switch. The limit signal should be off (no matter what the input voltage is) when the switch is not triggered.
You also need to check that the limit signals are enabled in the Mach ports & Pins dialog.
If you are using a parallel port, the MSM Hardware page will be of use. That page has two tabs; one shows the PP pins levels and the other shows the logical mach signals.

Dave

[grsabourin]

Thank you. I verify all these things tomorrow and give you news

[grsabourin]

Hi

I have performed testing following your advice. I have checked in input output settings for active low. I have reverse the selection and try to do homing again. MSM just gave me the error the homing switch is already triggered. I have returned to initial setting. Secondly I have checked the voltage on one of the trigger switch. With machine on an in waiting state I get 3.02V. When I push the switch I get 0.0 V and the led on break out board is coming on. Base on this information, let me know if you have more advice about this issue.

Thank you

[DaveCVI]

OK, we know:
1) that the switch is causing the BoB input to change state (as the LED for the pin on the BoB tracks the switch).
2) I think that the limit switch is logically connected to a limit signal in mach (because when you invert the active state mach complains that the switch is active).

Is this a "separate limit switch input for each axis" configuration or a "switches in series" config where one input is used for all the axes?

Dave

[grsabourin]

Is this a "separate limit switch input for each axis" configuration or a "switches in series" config where one input is used for all the axes?

Thank you again for your answer. Yes I have separated input for each axis. I think my current issue is just related to the x axis but other axis seems giving also strange results.