[1hander]

right now i have a c35s bob
uunless im doing it wrong ..im out of inputs
estop 10
probe 11
x y and z limits 12..13..15

i want to hook up an index signal for tapping... and also want to add a 5th axis down the road...
can you guys recommend a BOB that will allow me to do this ..

or can i add an expansion board ....
your input is appreciated as always

rick

[Fastest1]

You could hook all of your limit switches to 1 pin. Mach knows which axis is moving. This would save you pins and the purchase of any new equipment. 5th axis? What software?

[1hander]

hey boss

i tried using pin 11 for all limits... it wont work... im using c35s with the rj45 connectors... im thinking it automatically grabs a pin because of the way the rj45s are setup......the limit switch loom i bought is rj45... im not sure i can assign one pin... unless im doing it wrong..i tried assigning all linits to one pin ..11 then 12 then 13 ... but only one axis at a time would home ... its like the rj45 setup has already decided what pin its going to use..

unless theres a way to make mach forget what pin it used to have assigned to a particular limit i think im stuck

im working on a harmonic drive based trunnion table... planning in using powermill

[Fastest1]

Yes if all of the limit switches are connected to a single pin, only one axis will be in motion at a time during the homing sequence. Since I only home during the set up, there is no time advantage.

[CitizenOfDreams]

hey boss
i tried using pin 11 for all limits... it wont work... im using c35s with the rj45 connectors... im thinking it automatically grabs a pin because of the way the rj45s are setup......the limit switch loom i bought is rj45... im not sure i can assign one pin... unless im doing it wrong..i tried assigning all linits to one pin ..11 then 12 then 13 ... but only one axis at a time would home ... its like the rj45 setup has already decided what pin its going to use..

Well, first you have to physically rewire your switch harness so all of them are wired in series and connected to the same physical input. Can't do it in the software alone.

[109jb]

Well, first you have to physically rewire your switch harness so all of them are wired in series and connected to the same physical input. Can't do it in the software alone.

In series if using normally closed switches. If using normally open switches you would wire them in parallel

[CitizenOfDreams]

In series if using normally closed switches. If using normally open switches you would wire them in parallel

Yes, thanks for the clarification. Mechanical limit switches are usually normally closed for safety reasons - if the switch malfunctions, the wire gets broken or the connector gets unplugged, the machine will stop.

[ninefinger]

You could add a second parallel port card to the PC for additional inputs. Not sure how that works in Mach 3 but easy to do in LInuxCNC. The cards are super cheap (~$10) from various china sources.

Mike

[CitizenOfDreams]

You could add a second parallel port card to the PC for additional inputs. Not sure how that works in Mach 3 but easy to do in LInuxCNC. The cards are super cheap (~$10) from various china sources.

Mike

In Mach3 it is trivial as well, every input in the program configuration is defined by the pin number and the port number.

[john-100]

you might find its easier to wire the switches to the terminal block



how are the limit switches wired now ?

if its like this
Attachment 336040

with 3 pairs of series connected normally closed switches
you can not simply wire the 3 wires to the RJ45 pins 2,3 & 4 in parallel

the simple solution is to cut off the RJ45 connector and wire all switches in series and connect them to 1 input

alternatively find or build an AND gate interface to use the limit switches and C35 as supplied


original input wiring


using AND gate to connect 3 axis limit switches to 1 C35 input

john

[1hander]

rewiring is what i didnt want to do... since i am a beginner the rj45 stuff mades it clean tidy and easy ... for dummy like me LOL...
i can add another parallel port card but i dont think its as easy on mach as it is on linux for extra inputs..
and since i want a 5th axis capability.... i think im going to have to get a c32s or c62 and a c24 parallel port card

i see output expansion cards but i dont see any input expansion types...

[john-100]

if you had been happy building an adaptor this could of freed up some input pins _


Attachment 336086



alternatively by adding a second printerport and C10 bidirectional board
mach3 can either give you an additional 4 outputs and 13 inputs or 12 outputs and 5 inputs

since you only want to use ready made boards with the RJ45 connectors

it looks like the CNC4PC C32 dual port multifunction board and second printer port is the only option
as they don't seem to make a version of the C10 bi direction board with RJ45 connectors

John

[ger21]

but i dont think its as easy on mach as it is on linux for extra inputs..

It's probably even easier in Mach3.

[Fastest1]

Plug in the 2nd card and assign the address in Mach. Assign the pins. That is it. Though I didnt say it before, those RJ45's suck. I went that route at one point.

[john-100]

expanding on post 12
for any one taking a DIY approach to connecting the a ready made switch assembly like the A32R2 to the single RJ45-8 input
one possible solution avoiding cutting off the RJ45 connector from the switches
Attachment 336162

version 2
Attachment 336186

I must admit I would connect the limit switches directly to the C32 breakout boards terminal block

John

[CitizenOfDreams]

I must admit I would connect the limit switches directly to the C32 breakout boards terminal block

So would I. If you want to have a quick disconnect, there are industry standard two-part terminal blocks - much more robust and flexible. RJ45 does not really belong there.

[1hander]

i agree the rj45s make it hella confusing for me because theres no way to see which pin the contacts are assigned to..i know that now LOL