Costs

I am looking for a cost effective (cheap) PLC that can handle 4 analog inputs (4-20mA), 3 analog outputs (4-20mA), 8 digital inputs and 2 digital outputs. All of my experience in programming is with AB or GE fanuc. I am looking for something that can continually upload data to a pc once a day as well. thank you. adric

PLCs do cost (some more, some less) but the software costs as well.
What are you doing? Making 200000 identical machines using same
setupb and just one software licence or you want to make 1 project
cheaply? In first case software cost is irrelevant but not in the
case you do low volume. BTW what is your budget? AutomationDirect
has some reasonably priced hardware and software.

The Horner OCS may be the ticket. PLC software is free.

http://www.heapg.com/company/OCS/Horner Electric's Mini Operator Control Stations.htm

Here is a PLC possibility for you. entertron makes a PLC (link below) with 16 digital in, 16 digital out, plus an option board that covers your analog requirements. They have a HMI unit too. Give them a call and ask for Stephen, and he call probably tell you how to easily connect it to a PC.

http://www.entertron.com/elite.htm

regards....casey

PS, if you call them, tell them you were refered by PLCS.net

Take a look at http://www.controlmicrosystems.com/

mass production?

Unfortunately this is not going to be mass produced, and after talking to the company the other day they also would like the system to have the capablity to be expanded, I am not sure for what..... this is for a stand alone test bench and the process is very simple. But I guess you never know what could happen in the future. THANKS GUYS

Check this one:
www.tri-plc.com

Cheap alternative to PLC ...

I've been using this site for a while now, and thought I'd try & offer something in return ...

I've been using the Z-world line of products for a while now, and I've been very impressed (www.zworld.com). They have a line of single board computers that are very cheap. Many of them offer A/D or D/A converters. Most of them have at least 2 or 3 '232 ports, and 2 422/485 ports. Others are expandable with their proprietary RabbitNet bus (I think it is similar to a CAN or some other token-ring flavor).

The drawback to many will be that it is programmed in C. They have their own version, 'Dynamic-C', which appears to be a superset of ANSI-C, whith a lot of I/O functions built into the header files, and simple multitasking. There is even a FFT function! If you feel particularly adventurous, you can write inline assembler, for ISRs and such. If you've done much with RS5000, then it probably wouldn't be too bad.

If memory serves, the starter kit, with a PS, board, and programming software starts at about $250.

BTW: The big advantage (the reason I have been using them) aside from cost is the execution speeds. My interrupts get serviced and are completed in under 1 uSec! The SLC 5/03 doesn't have a timer better than 10 mSec.

Anyway, hope someone can use this.

-TJ

I saw Zworld mentioned in one of the previoius posts and thought I'd share a story that I can now finally look back and laugh about.

The engineering department at the company I work for purchased a machine a few years ago that was controlled by a zworld PLC. I didn't have anything to do with the purchase of the machine but was goinng to be in charge of installing and maintaining it so when the control panel showed up at our plant I was quite surprised to find this little zworld controller in it that I had never heard of.

I called up the Engineer in charge of buying the machine and asked him about the controller. The engineering department for this company was at the time without an Electrical Engineer and located in a differrent country. He told me that the machine was available with either this Zworld controller or an AB CLX. I was told that they went with the zwold because it was cheaper and that he didn't want anybody being able to "mess" with the program.

With my nose sufficiently out of joint I hooked up 480 to the control panel and closed the door.

The machine ran fine for about 6 months until one day I got called down to see why it wouldn't run. The little plc was flashing it's power light on and off repetedly. OH-OH now what? I didn't have any programming software to even begin to figure out what was wrong. So I tried calling the OEM, unfortunately about a month after we bought the machine they went broke.

Now the funny part;

I phoned Zworld to inquire about the programming software for this little guy. I was told "we do not sell software to end users, contact the machines OEM". After trying to explain to her that the OEM was out of business, my plant was at about 25% capacity because of the breakdown etc... I hung up. I was too flabergasted to even be mad.

Eventually we found the guy who programmed this beast and flew him in. After 2 days of troubleshooting we figured out that when a certain combination of operating paramaters was entered on the HMI the PLC had a math overflow and shutdown, powered up, shutdown etc.... there was nothing wrong with the controller.

I guess it was my fault in the end. I should have bought a spare PROGRAMED controller for this machine when it showed up.

nuff typin for tonight

have a look at www.wago.com.


it is a german plc with great expandabilities and cheap too. software is also cheap or when you write down what you want i will make program.
if only one system you can use the demo version of the software.

Low cost and reliability without worries about software licensing? I second the motion for the Horner OCS/RCS. They are simple to work with, the I/O stacks on the back of the OCS/RCS units. THe OCS is a PLC and Operator Interface built in, the RCS is just a PLC. The software if free and programs both the PLC and operator interface. The units come default with a CAN network and ANY OCS/RCS on the network can be accessed and programmed. You can also use DeviceNET without the need for extra software or hardware devices.

If familiar with GE Fanuc then Horner products will be familiar, they have been a 3rd party supplier to GE for many years.
http://www.heapg.com