PLC selection


Thread Starter

Charlie Waddell

I work for a company that manufactures HVAC equipment. I have an inside application for a filling station that will require the use of a PLC. It will most likely have 13 digital inputs and 7 digital outputs. Please help me select a PLC for this application. I will have to buy the software and cables as well. We currently use the Johnson DX-9100 and 9200 series DDC. The Johnson controller is not suitable for this application. Thanks.
You could proably use a Allen Bradley Micrologix 1761-32AWA ,1761-32AAA, 1761-32BWA,or 1761-32BBB They have 20 inputs and 12 outputs

Skye Controls

I would use the correct sized Allen Bradley Mirco logic series either 1000, 1200, or 1500, very cheap uses the same Rslogix software as the Slc series, and with the 1500 series you can get 12K, and a extra serial port for Hmi communication, and the 1500 series also supports analog.

Shahid Waqas Chaudhry

You can try the micro-controller from the PLC vendors. (like S7-200 from siemens, micrologix form AB etc) I have good personal experience with SIEMENS S7-200. Their CPU model 214 (14DI/10DO) should suffice your requirement. The new model of the CPU214 is CPU224. Same I/O and memory configuration but a smaller foot-print. Shahid

Scott Kortier

Check out Pro-face's Graphic Logic Controller (GLC), now sold through Xycom. This product is HMI and Ladder Logic built into one unit. It can have built in I/O or will work with a distributed I/O called Flex Network. It supports up to 1008 I/O points. Also Temperature Controllers are on its list of drivers. See
There are tons of PLCs that will do what you want. I would advise however, that you stick with Modicon or Allen-Bradley if you are not too familiar with PLCs. I have found that I get much better service out of these companies than the others. I have found training to be easier to get with these guys than the smaller companies also. I have had almost no hardware problems with any of the PLCs I have used, except Opto. The only problem I had with them was in a large network. They had problems with their communications drivers. I haven't use all of the PLCs listed here by other authors. They may be worth a close look. Just make sure you have a local supplier who is willing to service you when you have problems.
Take a look at KMC Controls it very user friendly and uses control basic code, plain english. Very inexpensive. uses one software package for programing and operations.