View Full Version : UIM2901-5A Mach 3 BOB wiring

29-01-2014, 01:22 PM

i am am now at the stage of wiring up to my BOB and have a few queries.

Im running a 24v dc circuit for my safety system and need to run one of the relay contacts to the limit switch or e-stop input on the BOB. Do I just wire the contact into ag and p13 or via the 12v terminal and into p13. (I am running the 12v into the bob so I can use the on board relay to control the dust extractor etc).

the same question applies to the home switches?

user manual can be found here: http://www.zappautomation.co.uk/en/attachment.php?id_attachment=90

29-01-2014, 01:50 PM
Just into AG and p13 like the diagram on page 4, same for home switches. The home switches can be wired in series and Mach3 will take care of it or if you like, though it's a waste of inputs, each switch can have it's own input. If you are using two motors for one axis, i.e. one is a slave, then it's a good idea to have another home switch for it but it will need it's own input. This is so the gantry can be 'squared' at the home position.

29-01-2014, 06:40 PM
Next question.... I was going to use the on board relay to switch on the spindle and dust extractor via the 2 no contacts.
The set up illustrated in the manual shows 3 outputs for the spindle - do these control the speed and the 2 outputs control stop / start?

i was going to use the 2 outputs to control a relay switching the power to the vfd on and off, is this the best way of doing it or should I add another relay controlling stop start and power on and off?

29-01-2014, 09:19 PM
Dan don't run the Home signal thru the relay contacts just the Limits. Take the home switch wires direct to the board from Ag to any spare input.

Don't turn the VFD off unless in emergency. To control Start/stop do this at the VFD using the outputs.
For best safety then wire the VFD thru the Emergency Stop system using relay contact to kill power.

29-01-2014, 09:51 PM
According to the bob manual this is how it's showing to connect the VFD


29-01-2014, 11:26 PM
Thanks guys. Think I will have to add another relay into my circuit. So 24v will come into cp1 out of cp2 to a relay coil - contact controlling the run signal. The second cable out of cp2 will go to b relay coil - contacts controlling the mains power live and neutral to vfd on/off as part of the the e-stop system. Will this work? Will try and get a sketch uploaded tomorrow to clarify.

30-01-2014, 09:19 AM
Before you do anything get the sketch loaded

30-01-2014, 09:10 PM
So far right diagram is 24v coming in from the safety circuit running through bob relay contact to control VFD then into the coil of a seperate relay controlling VFD mains power.
Left diagram is adding another relay in to control run signal on off simutaneously with power on off once the BOB relay is activated.
Middle option is to get a 3 or 4 pole relay (4 pole - leaving a space between power and control) to wire it all in as one, but would this cause an issue with interference?

30-01-2014, 09:18 PM
Just off to bed, have printed your drawing, will get back in morning unless someone else answers first.

30-01-2014, 10:13 PM
So far right diagram is 24v coming in from the safety circuit running through bob relay contact to control VFD then into the coil of a seperate relay controlling VFD mains power.
Left diagram is adding another relay in to control run signal on off simutaneously with power on off once the BOB relay is activated.

No Dan you don't want to be turning the VFD On/Off every time you run the spindle. You want the VFD power controled thru the E-stop so if an emergency it's shut down.
The run signal is used to start/stop the spindle spinning. Use the BOB relay output to control On/off just like Eddy shows lower down. Then have the VFD POWER controlled via a Relay in the 24V E-stop system.

31-01-2014, 10:23 AM
Cheers dean, will give you a call later to double check I get it

31-01-2014, 11:40 AM
As Dean says, like this;


31-01-2014, 02:43 PM
Cool. Thanks! I will be using the other bob relay to control the dust extractor on and off. Will this be ok to do via the 24v system relay switching the mains and the bob relay completing the circuit to power the 24v coil? Similar to how I was going todwitch the power to the vfd?

31-01-2014, 03:02 PM
Try this


31-01-2014, 05:27 PM
Cheers will get that sorted tonight! Does the run signal cable have to be shielded or will single core do?

next thing to question is the alarm output on the drives am882s. I've found a diagram of how to wire them (will drop the link in At some point) but when the alarm triggers the relay comes on and opens the circuit, should that link into the e-stop circuit or just one of the limit switch inputs on the bob as the diagram shows.
Im thinking not the e-stop circuit as this will cut power to everything including the drives. When a limit is triggered on the bob does it just stop the code running?

link to wiring diagram:


31-01-2014, 07:54 PM
The cable does not need to be shielded.

This is how I connected the AM882 alarms, see the attached drawings.

02-02-2014, 11:59 AM
Thanks for that mate. All sorted now. May be asking a few more questions later on down the line

11-02-2014, 08:09 PM
just wanted to check that everything seemed ok before i go ahead and wire it all up.

My questions are:

1 to kill the enable to the driver is it done via a relay contact - if the safety circuit is tripped the contact will open - as per the diagram? will each driver enable have to go through a seperate relay contact?

2 With the charge pump, does this disable the enable signal within the BOB if activated?

3 If there is no power to the driver, will it still provide a nc contact for the alarm? i want the alarm to break the circuit if it is activated, tripping the safety circuit.
4 Is the general wiring of the bob to driver and driver to motor ok ?



11-02-2014, 09:11 PM
1. You don't need a relay for the enable signal, just take a wire from the bob ENA terminal to each AM882.
2. Yes, when the estop signal is lost the bob will disable the drivers via the ENA signal and charge pump, that's why you don't need the ENABLE relay.
3. The default setting of my AM882's alarm signal was set so that the ALARM relay was 'off' when everything was healthy. If you want to change that you will need to use the ProTuner software and change the polarity (page 27 in my AM882 manual). Also it's not a relay inside the AM882 it's a transistor.
4. Other than you don't need the ENABLE relay the diagram looks okay.

19-02-2014, 11:28 PM
The cable from the bob to the vfd controlling the run signal - what size / rating should it be? I have some 2 core .75mm shielded left over from the limits is this overkill to use?

20-02-2014, 04:57 AM
It's only a low level signal so yes it's overkill, a simple twisted pair would do