Giant 20' x 3' x 2' router build

**irving2008** · 01-11-2014

Originally Posted by charlieuk

There are 6 in total 3 home 3 limit all pnp nc each one has a common + and - up to a junction box on the gantry were they go off on there own each have there own separate input wire on the csmio . the main wire is a 12 core cy screened and earthed at the control box all running on 24v

many thanks

So active low signal (i.e. break = limit/home hit), wired as per page 19 of the CSMIO/IP-M user manual?
.
I have to say I doubt line capacitance is an issue at the CSMIO end. CY cable is 75-150pF/m so looking at 900 - 1800pF for 12m. So when switch opens that 1800pF has to discharge through opto-isolator/resistor. Assuming standard 10mA opto current, series resistor is 2200ohm, so fall time is approx 6uS worst case. One simple & quick test would be to put an additional 2200ohm 1/2W resistor to ground at the switch end of the cable (or even a couple in parallel). This will discharge the capacitance faster and will reduce the effective capacitive load on the switch. Try that first...

**EddyCurrent** · 01-11-2014

Watching the video more closely, when the plugin filter is reduced to 1 (video at about 2:49min in.) the switch works as expected but the auto reset won't work. So it looks to me like it's the input filter setting that is causing the problem with switch not triggering. The issue is then, why does it not reset when the limit override is selected.

From the manual.

"5. If the machine has entered the hardware LIMIT switch, you can leave it by switching on the Settings screen "OveRride Limits" button. It is also convenience to switch "Auto LimitOverRide" - this will cause that while the raid on SW limit switch the machine will stop , but you can click RESET and le ave the limit switches without any additional operations."

Is it saying that "Auto limitoverride" is for software limits (SW) ? and "Override Limits" button is for hardware limits ?

Charlie, set the input filter to 1 or zero and see what this "Override Limits" button is.

**charlieuk** · 02-11-2014

Whew you set it to low when you hit the limit and then hit ether of the over ride buttons it triggers another e stop straight away so it it making it to sensitive. Like I said though when you shorten the wire it's fine and but I'm sure at one point I did have it going as is. We have some new switches to try so will be giveing that a go later

**charlieuk** · 02-11-2014

Ok so we tried the new switch with not much improvement so tony put his oscilloscope on it and basically the large kinco driver for the x axis is putting out a huge amount of noise.

**EddyCurrent** · 02-11-2014

The input filter in the plugin is used to stop spurious signals induced in the limits wiring acting as though the limit has been triggered when it has not.
If you are not getting these false triggers then the value in the filter setting needs to be as low as possible with zero being the best. Any higher setting is going to ignore the limit signal for a brief period of time and all that is demonstrated in your video.

It may be that noise is a problem once the limit has triggered but the main issue seems to be with resetting the system using some kind of override for the limits, I can't be more specific because I don't have access to a csmio board or plugin.
I do know that if you set up the software limits they should stop the machine before reaching the hardware limits and you should use those all the time, but obviously the hardware limits MUST be working for safety.

Are you using the most recent plugin software ?

**charlieuk** · 04-11-2014

Just a quick update. We have managed to sort the problem which was noise being created by the x axis drive and the long cable. We first re did some of the earthing on various bits and put them in a nice brass terminal block which made quite a difference. We then swapped the cheap Chinese proximity switches for some made by Schneider which cost as much for one as 10 of the cheap Chinese ones (should have know better). The last step was adding a small resistor on the csmio end and it now all seams happy.we also got the PC water pump running and even on the long pipes it still pushes a nice flow of water. We have also fitted a relay so that it switches on with the spindle and dust extractor. Not quite to sure what is left bar finishing trying to set it up on mach3 and learning how to use mach3 and load g code ect. Again if there is anyone anywhere near Brighton that can help me learn how to use mach 3 that would be a massive help.