Any Mags w/ Small Scale Control/Automation Experience?

[chmnyboy]

I have a friend setting up a small manufacturing operation and he needs some simple process control. We're looking at about 15 discrete I/O, 10 analog I/O (4-20 mA, I assume is the standard for instruments in this market), and a CPU capable of logic for the discrete and PID calculations for the analog control loops.

I'm well versed in industrial PLC and DCS systems (think GE and Siemens PLCs and DCS systems from Bailey and DeltaV), but I'm completely lost on where to start looking for small, cheap systems for small business users. The ideal setup would be something easy to program through a link to a mac/PC but would still have a stand alone CPU with expandable I/O. The ability to create a simple HMI for operations would be nice too, if only to avoid plugging in a laptop everytime a process change needs to occur. This won't be controlling critical operations, so redundant communications, power supplies, and controllers isn't necessary. Oh, and it would be nice to have some sort of historian capability to record and monitor process parameters, so maybe it would need a dedicated laptop to continuously record the data...but I don't know.

So...I find myself saying this a lot lately, but I want it cheap and easy. I would imagine there is some sort of simple product out there to cater to the small businesses, but I've been wrong before.

Any ideas?

[pruitt]

I work with HVAC controls but they are very capable of doing the stuff your talking about. Not sure what your inputs will be and what you will be controlling but I might have some ideas.

You could always use something like this:

http://www.grainger.com/Grainger/DAY...YP8?Pid=search

or

http://www.grainger.com/Grainger/SCH...NP4?Pid=search


I never have used them but seems like it would work for you. Just search PLC on graingers site. They have other items.

PM me if you want to chat about it.

[chmnyboy]

I work with HVAC controls but they are very capable of doing the stuff your talking about. Not sure what your inputs will be and what you will be controlling but I might have some ideas.

You could always use something like this:

http://www.grainger.com/Grainger/DAY...YP8?Pid=search

or

http://www.grainger.com/Grainger/SCH...NP4?Pid=search


I never have used them but seems like it would work for you. Just search PLC on graingers site. They have other items.

PM me if you want to chat about it.

Yup, that first link looks to be about right, assuming the programming capability is there.

Clarification of application: for example... 4-20 mA temperature transmitter, so obviously you'd want to be able to calibrate the controller so that 4 mA equals, say, 0 degrees C and 20 mA equals 100 degrees C. Once that signal is in the controller I'd like to be able to use it to control discrete outputs (like, if temperature > 50 deg C, then open water valve) AND analog outputs (either VFD vent fan or valve with PID calculation to hold temperature at 30 deg C) simultaneously. And I'd want the process values, controller outputs, and setpoints to be recorded to some sort of historian.

[Socialist]

http://netduino.com/

its like ~$30-$35 for a .net programmable microcontroller. I use it in a feedback loop for temperature control in home brew beer mash tun

[Snow Dog]

You're asking for a lot -- HMI, data logging, analog and logic. The big guys (Allen-Bradley, GE, Siemens) make little controllers too although they're probably not as cheap as you'd like. You'd still need a PC for programming and HMI. There's always Opto-22. Cheaper and more flexible than a full PLC.

[chmnyboy]

A little follow up for those interested:

I was able to score an old PLC from work that will do the job for now. No analog, but free is good, so I might be able to get away with it if I use thermostats, humidity switches, et al instead of analog signal instruments.

In the future I'll step up to an Allen-Bradley micrologix or SLC, each of which is capable of analog control and datalogging. I think a whole setup with cards, pcu, power supply, and back board can be had for a few hundy on ebay. The only thing missing is the PC software to program it, which I was able to get through a friend. If you have to buy this outright i've been told the software alone can be in the $5000 range. Ouch.

The netduino thing looks really cool. I might have to check that out for other small scale automation projects.

Or maybe I just need to go skiing.

[Power_Sauce]

Or maybe I just need to go skiing.

Yeah...do this.

[chmnyboy]

Yeah...do this.

Kinda hard for you to live vicariously when I'm such a nerd, eh?






LOL!