MEP-003A with PLC controlled auto start

[Triple Jim]

Here's one place selling it: https://solarconduit.com/shop/generator-start-control-module-gscm.html

You can get a generic programmable controller like an Omron Zen cheaper, but this controller might eliminate the need for some of the relays you'd need with a PLC. You'd still need things like an output contactor on a generator not designed for automatic control. Also, this controller is looking for the oil pressure and temperature switches to ground an input terminal on fault. They aren't wired that way on the MEP-002A or MEP-003A, for example, so you'd have to figure out a way to make that happen if you wanted the controller to handle those faults for some reason.

Not that you asked, but I prefer doing the job manually so I can wait five minutes or so to let my refrigerators and air conditioners de-pressurize, and so I can check the generator's operation in person on startup. I wrote a procedure for generator startup and shutdown so other family members can run it if I'm away, and they've been practicing.

 

[dfarr67]

I would prefer a few minutes warmup as well- due to the climate here. Mines a 5DJB contractors version- 12v.

 

[SteveH]

Yep!
To everybody who I emailed the PLC program to, here is how the connections should be made:

Power to the PLC: tb 5-10

Fuel pump/shutoff solenoid output Q1: TB 5-7
Manifold heat/glow plugs output Q2: K2-X1
Start relay output Q3: TB 5-9
Field flash output Q4: TB 4-10

Thanks - I was about to post a message looking for that info!

I'm doing the same thing, but with the intent that it will also be hooked into an ATS (closed contact to autostart). I'm using an Ultronics PLC I picked up off ebay; it's got a nice graphical front panel and also internet/GSM connectivity so I can monitor it remotely (and it can also send SMS/email if there's a problem).

One question: Did you power the PLC off the main batteries for the MEP? I'm thinking of putting a separate battery/UPS in just for the PLC, as I'm not sure whether the battery voltage will drop so much when cranking that it will kill the PLC?.

Also - do you happen to know what current the MEP heater, fuel and crank relays pull? (the PLC I have has built in relay outputs, and I'm not sure whether I can use those directly - I've not had a chance to measure the current on the MEP, but thought you might know...)

Given I've got lots of AI's on the PLC, I'm also planning on having it monitor Hz, Volts and (possibly) load.

Thanks in advance

Steve

 

[sewerzuk]

Thanks - I was about to post a message looking for that info!

I'm doing the same thing, but with the intent that it will also be hooked into an ATS (closed contact to autostart). I'm using an Ultronics PLC I picked up off ebay; it's got a nice graphical front panel and also internet/GSM connectivity so I can monitor it remotely (and it can also send SMS/email if there's a problem).

One question: Did you power the PLC off the main batteries for the MEP? I'm thinking of putting a separate battery/UPS in just for the PLC, as I'm not sure whether the battery voltage will drop so much when cranking that it will kill the PLC?.

Also - do you happen to know what current the MEP heater, fuel and crank relays pull? (the PLC I have has built in relay outputs, and I'm not sure whether I can use those directly - I've not had a chance to measure the current on the MEP, but thought you might know...)

Given I've got lots of AI's on the PLC, I'm also planning on having it monitor Hz, Volts and (possibly) load.

Thanks in advance

Steve

Yes, I ran the PLC off of the MEP's 24v batteries. This worked fine as long as the batteries were fully charged, but if they were depleted at all, then the relays on the PLC would drop in and out during cranking. To avoid this, I used a time delay relay for the cranking output. This would effectively "ignore" the fluttering output from the PLC. A better solution, of course, would be to use a standalone power supply for the PLC (or at least a regulated power supply).

I don't know current draws on the MEP's; I would have to go measure them. I can tell you that the glow plugs draw about 4A each (I usually test them with an ammeter when I am working on a new generator).

Your project sounds interesting! Post up some pics as it progresses. I had planned on taking my next PLC MEP project to a higher level...but just haven't had the time to do it.

 

[SteveH]

Yes, I ran the PLC off of the MEP's 24v batteries. This worked fine as long as the batteries were fully charged, but if they were depleted at all, then the relays on the PLC would drop in and out during cranking. To avoid this, I used a time delay relay for the cranking output. This would effectively "ignore" the fluttering output from the PLC. A better solution, of course, would be to use a standalone power supply for the PLC (or at least a regulated power supply).

I don't know current draws on the MEP's; I would have to go measure them. I can tell you that the glow plugs draw about 4A each (I usually test them with an ammeter when I am working on a new generator).

Your project sounds interesting! Post up some pics as it progresses. I had planned on taking my next PLC MEP project to a higher level...but just haven't had the time to do it.

Thanks. Based on that, I think that I'm going to have a (small) secondary battery and charger/UPS for the PLC. If the utility power has failed it doesn't sound like I can trust the generator batteries to keep the PLC up while cranking.

I definitely plan to post info - once I have something that (nearly!) works. I believe I have all the sequencing in the PLC done (including restarts, detection of faults etc), but haven't actually tried hooking up to the genset (or building it all into a box). The PLC I'm using (a Unitronics V230) is overkill for the job, but gives me the graphics, communications etc and the price (used) was a deal (built in HMI graphics are perfect for debugging). The good news is that the code should be compatible with their smaller units, which you often see on Ebay at under $100, so there's plenty of options to run the same code but without the 'nice to have' features.

 

[1800 Diesel]

I agree, this is way cool... I have used these controllers in the past, with good results (not controlling a generator, but would do that just fine). They are very reliable (the one I have has been tough) generally. And what I like is that the prices are very attractive as well... I'd wondered about that extra timer, thanks for explaining why you did that. I suspect on things like my MEP-004 I would not need that at all. In fact, I bet I could come up with a controller setup without any extra parts other than perhaps a relay or two (and maybe a voltage sensor).

Peter,

I'm setting up an MEP-004A for a co-worker and he recently asked me about installing an option for an auto-start capability. I believe he already has an ABT package for his existing 14KW natural gas generator (which he intends to sell) and is hoping he can keep the components he already has and then just add the PLC setup (or whatever is needed) to auto-start the MEP4. I am good for getting the generator to produce power and also installing a manual transfer switch, but am not qualified to install an auto-start system. If you have any details, please let us know. For his machine he will be getting a licensed electrican to do everything at his house, but he would like to know what's possible and what is not. Also if you or anyone else could provide a basic arrangement, wiring diagram and make/model for any components needed that would help quite a bit. Unfortunately at this time I don't know what make/model of the ABT rig he has (or whatever it is) but will have the info soon. Will post as soon as I have more details.

Thanks for any help you could offer. And a good weekend to all!

Kevin

Edit--In order to head off any concerns about hijacking this thread, I will start a new post with the above verbiage and will also include an update about the actual make/model ABT...

 

[SteveH]

I've been looking at the places to hook into the control panel today; with sewerzuk info above it looks pretty easy, but I have a question.

Looking at the electrical schematics for the MEP-003a, it looks as if the fuel pumps still receive power (and I guess carry on running...) even if the motor stops unexpectedly (e.g. runs out of fuel or breaks down). I was surprised - I'd programmed the PLC to shut them off, and I would have thought this would have been normal behavior (otherwise, I would have though that if the generator ran out fuel when unattended, you'd come back (at best) to dead batteries, and (at worst) burnt out fuel pumps.

It seems they are both wired pretty much direct to S1 Terminals 13/14 (which are shorted together). This seems to always be live when the switch is in the "Prime and Run" positions.

Am I misunderstanding something here? (or is there something about the pumps which makes it ok to leave them live?

-Steve

07-May; Bump - Still looking for some help on the above; looking at the description of the pumps they say they are 'self regulating' - does that mean they stop pumping (and drawing current?) if the motor is stopped, even if the switch is still in 'run'?

Thanks in advance....

 

[fredri]

Sewerzuk - I would appreciate a copy of your file for application on my MEP003A that I want to get start, stop and demand signals from my Xantrex Inverter when it sees the need for the gens help. I have an off-grd cabin with a 24 VDC battery bank an Outback solar charger and a 24 VDC; 4000 W Xantrex inverter set up. The cabin is at 5030 ft alt and temps get pretty low in the winter with lots of snow, as well as fewer solar charging daytime hrs, so batts can discharge more frequently without getting a solar catch up charge. Everything needs total hands off since we are away for long periods especially in the winter. Thanks in advance for any assistance... Fred Riebe: fredri@me.com (509) 952-2246

 

[jamawieb]

You are correct, if the motor stops and the switch is in the run position, the pumps continue to run.

 

[SteveH]

You are correct, if the motor stops and the switch is in the run position, the pumps continue to run.

Thanks. I wasn't comfortable with that, so I programmed the PLC to shut off the pumps if the motor stops running.

-Steve

 

[Triple Jim]

...looking at the description of the pumps they say they are 'self regulating' - does that mean they stop pumping (and drawing current?) if the motor is stopped, even if the switch is still in 'run'?

The pumps use a solenoid to return a piston and compress a spring. The spring then pushes the piston, which pumps fuel. If the output is blocked, the spring pushes the piston slowly, since its movement is only from leakage around it. When the piston reaches the bottom of its stroke, an electrical contact is made, the solenoid returns the piston, and the cycle continues. The pumps are self regulating because their output pressure is determined by the spring's rate, so it's nearly constant.

So current draw is minimum when the engine is stopped, but as you can hear from the clicking, the it's nearly the same as with the engine running. Maximum current occurs when the pumps have low flow resistance, and they are pumping a lot of volume (fast clicking).

It's a nice feature to have your controller turn off the pumps if the engine stops. It will be especially nice if the reason the engine stopped is that a fuel line broke or came loose.

 

[bimota]

I can highly recommend the Atkinson Generator Start Control Module for off grid homes and genset automation. The PLC learning curve will be steep though they are good tools, the GSCM comes with diagrams for many typical generators and inverters (Outback, Trace, Xantrax, etc.)

Generator automation is not rocket science but it can be tricky the microprocessor or PLC must mimic the manual starting process steps in the right order and with the right timing as well as be able to have fault logic to retry or shutdown as needed depending on the fault.

We've done a dozen or so auto starts on generators and I have to say that while they are great they can be a real time burner, especially if you have a generator with any fickleness. There can also be strange ground fault issues with solar arrays that are home spun combined with home spun auto start. We had a gas Honda generator we did the auto start on and it worked fine but when switched to propane the unit would not start consistently, so the whole setup ended up being frustrating.

If you want to do this with an MEP - make sure your 40 year old technology is working very well and is very predictable starting (in all conditions) before you begin automation.

 

[JKLeyden]

Does anyone know how to get a message to Sewerzuk? I jhave tried to send him a private message but it seems that his inbox is full and he can't recieve any more.

Thanks,
Jim

 

[PeterD]

If there is no private email option here, go to Youtube. He is active there and I think you can contact him that way.

 

[sewerzuk]

Does anyone know how to get a message to Sewerzuk? I jhave tried to send him a private message but it seems that his inbox is full and he can't recieve any more.

Thanks,
Jim

Hi Jim,

I just made some space in my inbox and sent you a PM