pls. help me on what type to use. it should be an allen bradley with a Rs232 port and can handle an analog input for resistance(thermistor)?

I dont know what part number of allen bradley that applicable on the above specifications that i need.

just post any message if you want to contact me. THank-you!

 

Summary: Seeking an Allen-Bradley with an RS-232 port and can handle an analog input for resistance(thermistor).

First of all, as much as I hate A-B's web site, it's not bad for researching this particular question. I went to www.ab.com and clicked on "Product Directory," then on "Product Overview" underneath "Programmable Controllers." Direct link is http://www.ab.com/programmablecontrol/

For myself, I can't stand using the older RSLogix 500 programming software, which means I'd pick a CompactLogix. I also can't stand programming over a serial link, so I'd go with a 1769-L32E, which has one Ethernet and one RS-232 serial. Of course, that Ethernet port costs a LOT of money, so you may go with the cheaper 1769-L31, which has 2 RS-233 ports. For that matter, an argument can be made that if you're used to old-school PLCs the CompactLogix is actually HARDER to use. Also, the CompactLogix is more expensive than MicroLogix, so depending on what you're doing it may be the better choice.

Basically, you haven't given us enough information to give you a good answer, and even then there would be several choices that boild down to preference.

Direct link to the area of AB's web site that deals with CompactLogix:
http://www.ab.com/en/epub/catalogs/12762/2181376/2416247/407648/


Direct link to the area of AB's web site that deals with MicroLogix:
http://www.ab.com/programmablecontrol/plc/micrologix/index.html

By the way, why the insistence on Allen-Bradley? A-B is a perfectly good choice, but there are plenty of others. The fact that you don't seem to know much about A-B put are insisting on it implies to me that some one ELSE is specifying it. Which begs the question why not just ask THEM exactly what they want?

-James Ingraham
Sage Automation, Inc.

 

I've been busy building a renewable energy business so I haven't been PLC'g in a long time. But, the good old SLC-5/04 and rack had t/c and thermistor cards as did the PLC-5 series. An RS-232 port can standard on most, or you could buy a comm card with extra 232 port(s).

Standard ladder logic PID Blocks allow you to convert the signal to a 0-100% output with response performance as desired. You should be able to refer the data table output value in a Message or Block transfer to send it where you want it to go.

I actually converted the 0-100% PID output to a 0-to-2 second on-off timer arrangement to convert the analog output to a digital-proportional switcher for 120vac, 0-crossover-fired, solid-state hockey puck relays for spinnerette 'doughnut heater' quench cabinet control on poly-fiber spinning machines. A-B actually made an A-D conversion Block (in the 5-series logic) to repeat my design as I recall.

If Ray Rogers with A-B can still be found via the Charlotte, NC office or A-B dealer you could track that methodology down.

I'll be doing SLC or Micrologix control on our sequential batch reactor (SBR) anaerobic digesters soon. We maintain 101F and 1/2 degree or less in this reasonably slow process with t/c's. You shouldn't have a lot of trouble finding what you need for RTD use in the catalog, or by calling Rockwell support for your RTD challenge.

Good luck.............

i&c_r_me

 

Do you have any suggestion what other PLC I can use regarding some specs that I gave? Thanks again sir!

 

i&c_r_me: "...the good old SLC-5/04 and ... PLC-5..."

I am vehemently opposed to using a SLC-5/00 or PLC-5 in new applications. First, you will be paying a LOT of money, especially in the case of the PLC-5. Second, although both will still be around for quite some time, they will start to disappear, probably ten years before the newer stuff does.

Having said that, of course there are plenty of applications using PLC-5 and SLC-5/00 today. This usually is a result of having a ton of them in your plant already, or not wanting to redo engineering and/or programming.

-James Ingraham
Sage Automation, Inc.