Newbie PLC data bit Issues

[shiggins0111]

Hi All,

I have searched for an answer to this on other forums but didn't find anything, so pls be gentle if there is.

I am new to PLCs but enjoying the learning curve. I have a question regarding the issues I am currently experiencing on a production line that uses an Omron CS1H with a cimrex 69 HMI. The issues are the following but NOT CONSISTENT which really confuses me and on each power down of the PLC gives a different scenario:

1: When the machine is firstly turned and initialized it doesn't always return the a cylinder to its correct position. I have checked the position of the cylinder before initialization to make sure the sensors are correct but its pot luck if it goes into the right position and will not run if the cylinder is not in the home position.

2: Sometimes the data bit addresses representing parts present on the line show that there is a part in the line but the sensor I/O for that part shows there is not? Again this is not always consistent when I reboot but I can't start a cycle until this condition shows there is nothing on the line.

Is it possible that the memory of the PLC could get corrupt by a poor grounding issue? It is using a dirty earth!

How can I check if the memory is corrupt?

This machine was working poorly but after being down for a day for electrical fixes! i.e. e stop reset button seemed to deteriorate even further!

Apologies if these questions seem a little dull!

Cheers all!!

 

[Ron Beaufort]

Greetings and welcome to the forum ...

I'm personally not familiar with your brand of PLC - but I'm pretty sure that some other forum members will be able to help you ...

you should copy and paste your entry to a new thread on the real Q&A board ... this is the practice area - and not many of the big dogs are going to see your post back here ...

good luck with your project ...

 

[Homer_BL]

CS1H is a good power PLC and I do not think that memory is broken.
May be you have an progremmer error or sensor malfunction.
Normaly, during startup, program is written so machine checks inititial position. If machine is not in initial position, PLC issues commands to put machine to that position. If some sensor malfunction, it will not be possible to do it.

 

[Goody]

We can't know from your description - but we can take educated guesses.

It sounds like bad/poor programming.

Any programmer worth anything makes sure he has a 'house cleaning' routine at the start-up or power initialisation.
And anything that is not right is reported on the HMI screen.

 

[shiggins0111]

Thanks for the rapid response lads, I'll be looking at this again tomorrow, in more detail. I will keep my progress (or lack of) posted.

Commissioning of it is going to be fun!!!!

Thanks again