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Limit switch problem


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Hello DT Support !

if you have a chance, please tell me.

I have PMAC 1.5 + ACC8D. 1.17H

Limit switches are used NC-types:


Switching collected as follows:


I use an external power supply.


I have a problem with the definition of limit switches. system does not have reactions to triggering limit switches. Status window does not display the connector state change switches.

if I'm doing the installation search for "Home" limit switch flag - motor spins endlessly, without response to the state of the switch.

Limit switches are working properly. built-in LED indicates operation of switches. PMAС to change the switch is not responding.

I found a similar topic on the forum. but there PMAC Turbo Clipper card. My board does not have the variable ix24.

What am I doing incorrect?


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HI Sina!

I set the variable ix25 in the correct values. it has no effect. also I change variables i907 and i908 (second channel PMATS). it also has no effect.

if I set the ix25 $C004 the motor does not have any movement. Status window also displays no change in the state limit switches.

http://i42.fastpic.ru/thumb/2012/0906/2f/b732453e3dc2857a3de26125ca46d92f.jpeg http://i42.fastpic.ru/thumb/2012/0906/97/6f04af829a430898800061a03e95ad97.jpeg

Installing variable ix25 is set to $2C004 (do not use limit switches) motor is moving. but also a status window does not display the status change limit switch.

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When the OT feature is disabled by setting bit 17 to one there is no status to report as it has been disabled. When enabled with bit 17 set to zero kill and re enable the motor. This should show the proper state of the switches. If you change the state of the switch and still do not see a change in the software this may be due to improper wiring.
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Sina, no :( I do not have a link to the technical documentation of end switches. :(

but they are intact and functioning properly.

I also try to replace one or more limit switches for "dry contact" switch. it just did not have the result: (


Steve.milich - Thanks. I understand correctly, you? - If bit 17 (i25) was set to off, the status of the state of the limit switches is to be displayed. and if bit 17 was ustnovlen to 0 to display the status of the switches must re-activate the motor. otherwise, the status of switches is undefined.


Today I'll be sure to try it. also check the wiring again.

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I did the following:

pulled the computer out of the machine. disconnected the cable from the computer to the PMAС of AСС8D terminal board.

Connect the other does not use the terminal board ACC8D. connect +12 volt to 59-pin. I also joined the "dry contact" switch (http://www.superdroidrobots.com/images/TE-044-000.jpg)

switch is set from 58 pin (AGND) to 52 and 54 pin. switch is normally closed.

Ix225 variable = $C004 and stored in the memory board.

I send a command "Jog" or command "Home".

in the status window, I see the connector pin status change (for motor 2) "motor enable" from red to yellow. when open microswitch status pin "end switches" does not change. :(


I also expect that there should be a red pin "amplifer fault". but it also remains yellow.

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If the +/-12v and +5 is properly wired you can test the functionality of the OT inputs by resetting the PMAC with the “$$$***” command and activating all the motors by setting I100=1, I200=1, I300=1, and I400=1 note that I100=1 is set by default after the reset command. At this point you only need to wire the OT inputs to ground as a test.


+LIMn and -LIMn are direction-sensitive over travel limits, that must be actively held low to permit motion in their direction. To implement limit switches, wire the input (pin 53 and 51 for channel 1 +/- limits) to one side of the limit switch. Wire the other side of the limit switch to PMAC's AGND (pin 58).

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You can disable the position limits by changing bit 17 of Ix25 to a 1 (see page 97, PDF page 79 in the Software Reference manual). Or, tell me what Ix25 is now, and I will tell you what the new value should be.


If you disable the hard limits with Ix25, you could regain some level of safety by setting software limits with Ix13 and Ix14. Note that these limits will be in the wrong place before the machine is homed.


Do you see the limits if you simply remove/attach a wire between a LIM input and AGND? I would follow the instructions that Steve posted, except try a wire instead of the switch.


To return the board for evaluation/repair, contact your distributor or go to the website at Services \ Repair Request and fill out a repair request. You will need to "Create New Account" if you are not already registered. Enter my name (Greg) in the "Engineer Contacted" field.

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Thanks Gregs!

I disabled the position limit. (set i225 = $ 2C004).

Now I will try to set up the software to run without limit switches.

If I attach/remove the wires for the limit input and AGND - I do not see any change in the status of Lim inputs.

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  • 6 months later...

Hello! I won it !


the problem was in the original solder contacts.

I repaired it. now everything works!


http://i53.fastpic.ru/thumb/2013/0327/82/03245451a17b5f9f3c366b03d8193a82.jpeg http://i53.fastpic.ru/thumb/2013/0327/c7/d9acf7d88ee561d61a6984fca3a6b4c7.jpeg


I thank everyone for their support and I have a few more questions :)


1. if I use as a control program Mach3 (as done here: http://www.cnczone.com/forums/knee_vertical_mills/72957-supermax_kmc-40_w_micropath_series_40_control-4.html#post600700)

Will work s-curves function ? as I understand it, drive control functions should work with any command input method. or am I wrong?


2. Are there examples of PLC for simple control panel on the J2 connector?

(I have problems with programming and I can not get the remote to work :( )

I will be very grateful for your help.



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Hello. Thanks!

In such a way PMAC delivers smooth and precise motion, regardless of the method of reception of the task.

I understand you correctly?

MACH is a temporary solution. You understand the impatience to see how the new machine. :)

I have NC2.36. and made the console:


http://i52.fastpic.ru/thumb/2013/0329/53/d197fbdb718ffd1ef9a848a7286cf753.jpeg http://i52.fastpic.ru/thumb/2013/0329/6d/701ac54a5c56a37a39f9c0ccf04b836d.jpeg


Console connect to "control panel" port.

functions that are necessary for me I mounted on the console.

others, such as the "axis of choice" for Jog movement, override, work mode, and another I hope to use the screen SC.


but I'm not the best programmer. I need a lot of time to understand and change PLC.

particularly hard for me to understand what variables are used in NC.



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you can tell me - what and where should I change for this to work without ASS34 ?

sorry - I'm a bad programmer :)

I see a lot of variables. I understand that to be changed addresses.

but I can not understand where this should be done.


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I'm using a direct connection to JPAN connector.

the scheme looks like this:




All buttons NC type.


I was trying to write his own PLC:
















//JOG -



















IF (M25=1)






IF (M26=1)








if I download it through PEWIN - everything works.

but if I try to use it at boot NC ...

there is no movement .. Why is that?

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+1! Steve, can you more detail ?

I see in the manual PMAC - variables be assigned to certain functions. For example, M20 displays the status of the 4-pin JPAN port....

if I can not use them - how do I get the status of my buttons?

You can make example for understand how I do it?



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