Limit Switch

[damunk]

I have wired two limit switches on my servo drive.

The are basically very simple to wire. two pins from the connector represent inputs clock wise and counter clockwise.

So you wire each to a ground and the limit switch in-between causing the break in connection and should result in the stopping of that particular movement.

You also have two choices of parameter as follows:
0: the disable inputs of CW & CWW are effective
1: the disable inputs of CW & CWW are ineffective

But what happens is soon as limit switch is engaged then an alarm comes up which is "driver disable abnormal" - CWW and CW has no input or parameter is not 1 Check parameter and CW, CWW wiring"

I have tried both parameters and tried wiring both normally open and normally closed on the limit switches.

They both go to the same ground yet don't share the same ground wire if that makes sense.

I must be missing a trick here.

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[damunk]

http://maxcdn.cnczone.com/images/attach/jpg.gif

struggling with this still.thank you.

[CNCMAN172]

Damunk
The way most servo drivers that have CW and CCW inputs is to limit movement in y
That given direction when that limit switch fires. According to the schematic you posted the limit switches should be normally open and close when yo reach the respective limits. The ground then flows through the closed limit switch contacts and provides that ground to the driver input either CW or CCW. Most drivers also require you to enable them inputs by programming the servo driver. Not sure which driver you are using

[damunk]

cncman172: Appreciate your reply. Yes when the limit switch is activated the ground runs through this switch and into the INPUT CCW or CW depending on which limit switch was triggered.
This is when alarm 7 comes on instead of it just stopping the motor in that particular direction.

I have checked the wiring. Because it is so simple to check the wiring.

A standard limit switch allows you to wire in normally open or normally close. Have tried both ways. It must be driver setting.

Please find manual attached. Would you be kind enough to check parameter 20 and parameter 55. pages 27,29, 54-63

https://expirebox.com/download/17831...0370318f1.html

[CNCMAN172]

Damunk
The way I read the manual PA20 must be set to 0. PA55 is either 0000 or 1100 the manual is a little confusing. I would try 1100 first. Another part of the manual seemed to imply you can use your limit switches, but if you have a parameter set wrong the driver sets the limit error flag and the other way it just disables additional motion in that direction

Russ

[damunk]

Dear Russ,

I managed to get it going but want to ask if the following is strange behaviour.
CCW Limit switch stops the motor rotating CCW but allows CW to return to normal position.

But when the motor rotates CCW again and hits limit switch again: Alarm "driver disable abnormal"
So it all works the first time around but not the second time around. Is this normal?

Parameter was set to 1110.

editL grrr getting fed up of this. It only works once.After that either limit switch used again will bring up alarm. 1110 must be wrong. 1111 is very wrong because it just enables the servo without using a switch.

edit 2: found another problem. both limit switches work for the same direction so there must be a problem in the wiring. They use the same ground on the circuit but one limit switch is used at a time so I don't know they can be interconnected.


Conclusion: Maybe this is how it is supposed to work.

[CNCMAN172]

damunk,
Sorry for the delayed response was flying back home all day yesterday. Keep in mind when you tell the servo drivers to stop motion when a switch gets activated by the CCW or CW switch you are telling it you know you are at the limit and want to be able to go the opposite way. This is really used for jogging. If you jog your machine around and get too close to the limit on one edge you want the machine to stop so it does not damage something. Then you jog in the opposite way to get away from the limit switch that fired. Now all of this can be independent of how you want the CNC software to respond. I believe you driver allows you to program the CW and CCW inputs to act as limit switches which is an error condition if you hit a limit and are running gcode, it knows that limit should never be hit. If you are jogging around it knows we can all do something stupid and get too close to the edge and don't want to completely reset the machine just get away from the edge so it allows motion to get away. During Gcode runs normally that is not the case, because whatever you are cutting will probably get ruined and it knows something has to be wrong.

Russ