Is anyone using a PLC, Programmable Logic Controller for a grow room controll??????

Well as the saying goes, "if it has tits or gears, its gonna give you trouble"

If an I or O fail, is because of poor design on *your* part 99.9% of the time.

The PLC is a MUCH more reliable solution over a ground up roll your own. And far better then a PC based system. ( unless windows and its programs never crash. same for linux or other fits-all-do-all OS) A crashed program/OS is no better then a stuck I/O.

AB? I'd never use a AB brick PLC. Too pricey for what you get. AutomationDirect gives way more bang for the buck. DL06 is nice and can add in a ethernet module.

For AB, I start with 5/03 and a rack.

I'm also perfectly fine in my ability to program a PLC and safety interlocks.

As to the flood, thats a poor design. Yes a stuck valve caused the overflow, but where was the safety alarm when the water hit the floor?
Or the flow meter seeing a flow for 12 hours?

(and what about a simple MODbus? No killer software)

chiefbootknocker said:

ha until you have an input or output fail when you aren't there. I programmed a tank filling automation sequence where I worked, and it worked great for the application. After I left that job I was talking to a co-worker from that job about something else, and during the conversation he told be that the valve that I was using to allow the water to enter the tank had stuck (mechanically) open and they came into a flood the next morning.

That is something to consider when implementing a PLC. Imagine a mechanical component failing. Depending on what that component is, and your faith in your programming and equipment i.e. your ability to react to the failure, you could take out your grow, your grow room, or worse. Especially if you are a novice programmer I wouldn't do it. Taking NO/NC contact and energizing a coil is a piece of cake. Having the knowledge to program safety circuits takes some experience.

As far as getting information to a web browser, I'm not real familiar with picos, but most lower end AB does not have ethernet, but in some cases you could tie an AIC module to the PLC and get ethernet through that. The issue becomes transferring the WORD information out of the PLC and then either using some intensive VB code to create a front end for it, or get something like Wonderware and create a GUI from that. Then the PC running Wonderware could have a second eth card installed going to the web and you could just RDP to the PC from remote locations, and control/monitor that way. At any rate quite elborate. May be good for someone growing huge amounts of weed, and wanting to keep clear of the grow site, but still have the process completed. But if you just have a small grow going then I would think money wise and effort it's not worth it. How ever you proceed good luck

Click to expand...

BigBudBalls said:

Well as the saying goes, "if it has tits or gears, its gonna give you trouble"

huh?

If an I or O fail, is because of poor design on *your* part 99.9% of the time.

Not true at all. I have seen input fail because they were clacking at 300ms for 16hrs a day that were used for an incoder sequence. I've seen outs fail too. These are after 3ys, some less, but it happenes. There are also mechanical failures too.

The PLC is a MUCH more reliable solution over a ground up roll your own. And far better then a PC based system. ( unless windows and its programs never crash. same for linux or other fits-all-do-all OS) A crashed program/OS is no better then a stuck I/O.

I agree if you do it right.

AB? I'd never use a AB brick PLC. Too pricey for what you get. AutomationDirect gives way more bang for the buck. DL06 is nice and can add in a ethernet module.

Micrologix are cheap too, and AB is much more transperent across platforms because they are the industry standard. AIC's add eth, and the 1500 micros have add modules not sure the price though.


For AB, I start with 5/03 and a rack.

Why. By the time you get a rack, a PS, CPU, 1 input card, and 1 output card you have spent enough to get a few 1000's with the same fuctionallity. Now if you were to comeback and say the rack gives you the flexibility to add modules for expansion I would say once again seems like a lot of money and time for a few indoor pants.

I'm also perfectly fine in my ability to program a PLC and safety interlocks.


Hey that's great. I sense a bit of offence in that and let me say that the mechanical thing I mentioned to you was the only comment directed to you as sort of that haha thing that happens in the industry from time to time, but maybe you haven't experienced it. The safety thing was directed to the original poster as a precaution because he sounded like a novice, and it's good information.


As to the flood, thats a poor design.Yes a stuck valve caused the overflow, but where was the safety alarm when the water hit the floor?

Well you know it's just one of those things. It was not a budgeted project so I was forced to use what was available (scrap) to me. As a matter of fact I had to make my own home made float switch.


Or the flow meter seeing a flow for 12 hours?

YEAH RIGHT. What will that do? The pickup will detect flow through the meter, but if the valve that controls the water is stuck open and can't shut what exactly with that flow meter do to shut the water off???? The only thing I could have done to improve that was to build redundancy, but I couldn't due to the above answer.

(and what about a simple MODbus? No killer software)

Click to expand...

Never used in my industry, but sounds great for the home brew guy.


Also in case you didn't see, the rest of this is inside the quote.

chiefbootknocker said:

I'm also perfectly fine in my ability to program a PLC and safety interlocks.


Hey that's great. I sense a bit of offence in that and let me say that the mechanical thing I mentioned to you was the only comment directed to you as sort of that haha thing that happens in the industry from time to time, but maybe you haven't experienced it. The safety thing was directed to the original poster as a precaution because he sounded like a novice, and it's good information.


As to the flood, thats a poor design.Yes a stuck valve caused the overflow, but where was the safety alarm when the water hit the floor?

Well you know it's just one of those things. It was not a budgeted project so I was forced to use what was available (scrap) to me. As a matter of fact I had to make my own home made float switch.


Or the flow meter seeing a flow for 12 hours?

YEAH RIGHT. What will that do? The pickup will detect flow through the meter, but if the valve that controls the water is stuck open and can't shut what exactly with that flow meter do to shut the water off???? The only thing I could have done to improve that was to build redundancy, but I couldn't due to the above answer.
Never used in my industry, but sounds great for the home brew guy.


Also in case you didn't see, the rest of this is inside the quote.

Click to expand...

I went with the keep it simple theory for this bit. I use a float valve (a cistern type) for water top up to my main res from a gravity fed RO res. The intention is the PPM will then decrease, the RTU detects this and runs the dosing logic based on predefined min values.

I have an over flow outlet from the main res mounted just above the float line which is drained straight out to waste. A controlled pump fed from the RO res to the main res operates if the dosing overshoots a max PPM value until the level is diluted. Obviously the same logic runs anyway to maintain the plants requirements.

A logic watchdog point brings up an alarm locally via assigned LED and remotely via Citect if PPM drop below a lower min level (or above a max) this should give me time to rectify the problem before plants suffer and with no spillage.

I would never have an auto filled res if it weren't able to drain overflow un-aided. Worse case I lose a few days worth of nutrients if there is any failure.

AB is industry standard in the *USA* Europe prefers the Siemens. Asia, surprise, like the mitz, Omron, and other asian PLC.

MODbus is an *open* standard unlike the licensed /perverted DH485 of AB. (also there is Profibus, also open)

AB is great stuff. Overpriced software to program the things. For smaller projects the DirectAuto stuff wins. (1/2 the price of AB. With AB, the part # *is* the price. $1200 for the standard RSLogix 500? Now add in RSView with a fair amount of tags, PanelView 32, etc, it adds up fast, and thats even before you buy a single PLC or module.) For bigger projects the AB wins.
A grow room, even multiple is a small project.

And the B&B programmable relays for starting at $99 for a grow room fit just fine. (free software, but the things won't do math, but will do AI, MODbus Profibus, and I think ehternet)

There is a world beyond AB. Don't get stuck on just one brand; its bad biz.

I can sympathize with you on the 'not in the budget stuff'. But most of my customers have the cash to do things right. The extra $2-4K is a drop in the bucket to get it right. Plus most are ISO and have to. But there are always a few that bite off more then they can chew. Did a job late last year. Manufacturer lost the PLC program. So I had to for what I had to to make it work. My bill was just over $40K. (was a happy pay day when that check arrived. Perks of being self employed.)