Carwash vacuum/indicator project

Hi Our carwash has a central vacuum system with a 15HP producer, running 16 individual drops. Currently, I have a magnet/sensor combo on each drop, wired in series to a relay, to the NC state. When all nozzles are docked the circuit is complete, the relay switches off the run command to the VFD that I use to run the vac motor. I would like to update this system to use a contact closure detector, such as ZSCAN16PROXR, and a simple relay controller such as PR16-10. The idea is to program such that when any switch is open (contact closure open) the relay would provide to run command to the vfd (itself being a simple contact closure) and when all switches are closed, the motor stops. I would also like to add a light (LED) to each station that would typically be green when docked, red when undocked. Or, blinking green when undocked, this might save circuity as I would only need 1 or 2 wires per station. would a pr- 22-1 be the appropriate controller for this? Any advice or thoughts are appreciated. Thanks in advance!

Hi Patrick,

So do I understand correctly that all of the sensor switches at the 16 vacuum stations home run back to 1 central location where the vac pump is installed? If you had a board there which monitored those 16 switches and automatically controlled a relay to control the VFD would that suffice or do you actually want a computer there running software for other purposes? If you do want software running there to perform other services what is the purpose of those services(Remote monitoring, notifications, etc)?

As for the red/green lights at the 16 vacuum stations would this be hardwired back to the central “hub” locations where those lights would be controlled over a hardwired location or would it be better to install a board there which also monitored the local switch and automatically controlled the lights, sort of a stand alone device.

Hi Travis thanks for responding. Right now, since it is a simple series circuit, there is 1 wire leaving the maintenance room at the power supply and it is routed thruout the cleaning area and then back to the maintenance room. I would upgrade the system by running a cable to each switch back to the central location where I would use a computer already there doing other work. Hence the contact closure detector. I would then cable out to each drop station for purposes of a light. Hopefully I could then monitor the status of each station, either on the computer, or observing the light. The main point is to find which station is at fault in the event that the vac continues to run after all stations are docked, right now I would have to go around to each one with an ohmmeter to find the offender. I currently use the NC contact of the relay, in case any switch is bad (open) the vac continues to run and be used by the crew.(default on)

Hi Patrick,

What you are describing is definitely possible. Do you have software development experience? We can provide the hardware you would need for this application but if you want to process everything through a software application then some software development is going to be required. We do not have an off the shelf software solution I would recommend for your application.

From what I understand it sounds like you would need a 5 conductor wire run to each of the 16 drop stations. 2 wires would be used for monitoring the switch and the other three would be used for controlling the lights there(red, green, and ground).

If you have software development experience please let me know and I’ll recommend some hardware.

Thank you,
Travis Elliott

Unfortunately I dont have much experience beyond some knowledge of computers, and some configuration of devices that we use in the carwash like VFDs and zelio smart timers, carwash controllers. But, my boss can possibly do this if were simple enough… arent there various platforms that could be used like cplus or basic? This should be simple to do, as I am only controlling the relay, when all vacs are docked, and turning on/off lights as per switch status. Doesnt need to be any more complicated than that.

Or does this use the base station software to do what I want? That looks like something I could learn. Perhaps you could recommend the hardware, then suggest a s/w I could look at, and see if it works for us. Thanks for you help so far!

Hi Patrick,

What you would need is some automation software which would read the inputs on the ZSCAN16ProXR then depending on those inputs control relays which would control the lights at the drops and the input on the VFD. You might look at They have an application called N Button which may do what you want. N Button should be able to monitor those inputs and then control relays on a ProXR series relay controller.

Thanks Ill look into that. Should be able to do a light controller as well?

sorry I meant do I need a separate light controller or is there one piece of h/w that I would use for vfd and light control.

Hi Patrick,

We don’t really have a specific “light controller” product in this line of products. The best thing we could offer is a simple multi channel relay controller. If you need to control 2 lights(red and green) at 16 drop locations plus 1 relay to control the VFD that would mean you would need 33 relays. I’d recommend a 32 channel ProXR relay controller plus a 4 channel XR expansion board. Linked here:

ok. that gives me something to work with. I suppose I could combine functions, as in using one relay to turn the light on, and make it flash depending on switch status and software. That way only 16 plus 1 relay

LIght on when docked, same light flashing when undocked I meant

That would certainly lower the cost/complexity of the system if you could get away with just one light solid or flashing depending on status.

Thank you Travis. Let me present this to the boss

Ok after studying this some more, would this combo work?
A zscanpro16r scanner for contact closure detection,
A PR1-14 relay controller, ( I could use the SPDT NO and NC circuits for lamp operation.)
and a PR13-30 relay controller for the signal to run the vfd. It is a very low power signal, needs contact closure only to run.
Am I correct in assuming that communication protocols would work for all 3 devices? and I could use the software that you suggested, from serialport tool?


Hi Patrick,

PR1-14 is an IoT interface product. It is assumed that the user will install a processor module and develop firmware to run on that processor to work with custom developed software. This would absolutely be possible but it would be 100% up to you to develop firmware to run on the relay board and to develop custom software to monitor the ZSCAN board and send commands to operate the relay controller appropriately. This would not be compatible with off the shelf automation software like N Button.

I would instead recommend this 24 channel relay controller to operate the lights and the VFD:

It’s possible you could monitor the ZSCAN board and control the relays autonomously using the N Button software available here:

Keep in mind we are not the developers of N Button but it is compatible with our products. I would recommend contacting them and discussing your application with them prior to purchasing. See if they think it will work for your application. They can provide support on it.