I need help programming a Idec Micro1 plc with a ladder program. I have very little experience with plc programming and I need to write a program that will automate a machine I am building. I will need many control functions such as estop, jog forward, jog reverse, start, stop, count up/down, if count = then, etc.

I know what the basic instruction set is and how it works, but I don't have any practical experience. My first problem is how do I get the estop to stop an entire block of program without having to enter the LOD out for the estop in each rung? Also, when the program comes to the END function, does the plc stop or does it simply go back to rung 1? If any one has a sample ladder program that has an estop and multiple motor start/stops and a counter perhaps in that program, I would really appreciate it. I just need an example of how it all works together so I can get this machine running. I can provide a flow chart and input/output list if needed.

Thanks in advance!!
bnelson

 

Are you sure you want to use the Micro1? It has been discontinued for 2 years now, and it's not the easiest of PLCs to learn with, the software style is a bit dated. Could you not use a more modern PLC?

If you are using the Micro1 anyway, then the 'END' is just the end point that tells the PLC to go back to the start of the ladder and scan again.

There is a MCS master control function that you could use with the estop, but I can't remember if it turns off the outputs within the MC loop while it's on. It's a long time since I did Micro1 stuff.

 

Using a plc for an emergency stop function, i.e. switching off outputs based on the state of an input, is both bad practice and will not meet machinery or safety regulations in any country. Depending on the risk, (you will need to do an assessment based on the local safety/machinery legislation) you should be using a safety relay with guided contacts, redundancy and cross checking. I suggest you take some advice from a safety equipment supplier (Allen-Bradley, Pilz, Dold) before proceding with the PLC issue.