PLC and VFD controlled self service bays

[German Ace]

Hi all!

First of all, I'd like to thank everyone for the help! This forum has been very usefull, since I'm trying to setup a SS carwash outside US, and the experiences described here are priceless!

I've already read many things about PLC and VFD delivering high and low pressure options through high pressure pumps (all using the same gun), and I know it is possible.

Does anyone have some schematic, picture, describing this kind of setup / programming?
What are your experiences?

This would be very helpful!
Thanx in advance!!

 

[MEP001]

I don't recommend the setup. It works, but it's usually not very efficient. Some of these systems are so over-engineered that they're very troublesome. The only real advantage is the reduced apace it takes up.

 

[Randy]

When I was with the Nuclear Navy my boss Admiral Hyman Rickover was a firm believer in the KISS principal, “Keep It Simple Stupid”. The simpler these systems are the easier they are for you to work on them. All these systems can be controlled by a VFD or a PLC but when they fail and they fail it’s very expensive to repair them. A friend of mine installed new equipment that the low pressure functions were controlled by a VFD. As soon as the warranty expired they started to fail, at $900 per unit he removed the VFD’s and went to a Procon pump controlled by a IDX MX-8 Multiplexer.

 

[Axxlrod]

Don't do it.

I have one, and it was a mistake.

It was really cool on the convention floor when I first saw it. All functions through one pump, and the vfd adjusts the speed/pressure for each function.

However as the system has aged, parts and more importantly the programming are no longer available since the manufacturer has gone out of business. Once the plc goes, the whole system will have to be scrapped.

Just keep it simple and buy a separate system for the low pressure functions.

 

[mjwalsh]

It does appear ... at first glance ... that the one pump for both low & high pressure functions is simpler with a lot fewer components than two separate delivery systems???

What Axxlrod said about PLC-VFD programming being no longer available would definitely be a "no go" for me. I would want upfront from the manufacturer-distributor complete access to all the code ... in such a way another replacement PLC-VFD could be put in their place & the Ladder Program & VFD configurations would transfer over with no problems.

Are the only concerns mostly ... the more intricate PLC-VFD programming & configuring like Axxlrod seems to emphasize??? I notice ... there are a lot of reasonably priced off the shelf PLCs & VFDs available online. When you get into safety certified PLC setups ... it seems like that is when the price might skyrocket. I personally think that ordinary PLCs would be safe enough for self service operations similar to non PLC-VFD driven self service operations.

 

[MEP001]

It does appear ... at first glance ... that the one pump for both low & high pressure functions is simpler with a lot fewer components than two separate delivery systems???

No, it's not. It's more complicated, more finicky, more expensive, it still has all the parts as a conventional system. D&S along with Hydrospray have a setup that needs no tanks, and it's an absolute nightmare to work on or even diagnose anything. It's supposed to save space, but it saves very little over the equipment it replaced.

I would want upfront from the manufacturer-distributor complete access to all the code

That will never happen with nearly all manufacturers. I hope I don't have to explain why.