Who Has FREE PLC Software?

I know Allen Bradley RSLOGIX is far from free, and their support program is far from free so I am looking for advice on PLC selection. I am going to add several small PLC's to some equipment in our shop so I am considering other PLC manufacturers.

Mainly I have decided to base my decision on the price of PLC software. I made the following list with names that I am familiar, but if you have any other brands of PLC's with free software, please enlighten me.

• Allen Bradley (not free)
• GE / Fanuc
• Mitsubishi
• Omron
• Schneider Modicon
• Siemens

PLC Input Card Fuses Do they exist? Can you change a fuse on a PLC input that doesn't respond to a voltage input?

Thank You!

I decided to try changing the wire to another input that wasn't being used. I was able to change the address in the ladder to reflect the wiring move on the inputs. It worked. I should have just tried this on my own but I wasn't positive that I was on the right track.

Next questions:

What causes this?

Can I just leave this alone now or do you think that more of the inputs will start to go bad?

Also, are there internal fuses or anything I can repair, or should I replace the card?

Thank You!

Hello,
I am new at this so please excuse the question if it is something simple.

I have a PLC Input that is not responding. Let me explain. The machine has a basic limit switch with a mechanical contact. It is attached to a swinging door that is pressed down with the weight of the product which is in boxes. (The product doesn't matter here but I thought I would mention how simple the situation is.)

The limit switch is closed. I have tested it with an ohmmeter. I have also verified with a voltmeter that there is 24V at the input of the PLC, but the PLC input is not responding.

The input card on this PLC also has LED indicators. The indicator lights when we close the switch and goes out when we open the switch so I am convinced the circuit is working properly.

Is it possible that the PLC input has an electronic failure. I have heard that a PLC input not responding to voltage is rare.  Thanks for any help with this matter.

MadChad