reset the register

I am working with Siemens 545-1106 PlC. I been having problems with the register reseting. I have been doing a full restart of the plc to reset the register. I am in maintenance in a distribution facility. I have worked with AB, Omron, and Siemens plcs.Does any have a better way of reseting the register?

Can you clarify?

What do you mean by reset the register? Which register? Are you looking to change the value of a "V" memory location? Do you have programming software?

Ah, the register. Which register would that be, then? I know the 545 CPU but I don't know what 'the register' could be, far less why it would reset.

And your post seems to say that the problem is the register resetting, and yet your solution is to restart the PLC in order to reset the register?

A litle more precision and detail required before I can help any further, I'm afraid.

Regards

Ken

I am trying to rest the bit register for it seems to lock up and the plc will not function correctly.

Is this a programming instruction rather than a memory area? Is this a shift register? Is there a box in the ladder labelled SHRB?


So many questions, so few answers, as yet

Are you referring to a bit shift register (SHRB) instruction?
If so it should have an enable/reset bit, when this bit transitions from true to false the SHRB clears, all control relays clear to zero.


Is this an application that was working, and now is not? If this was a once functional program, sounds like something else is the cause, and the SHRB is just the symptom.

Can you post your code? Exactly which network is causing the problem?

yes It is the SHRB. The enable/rest will not reset. The control relays will not reset to zero. It seems like it is in the memory location and that when I do a full restart, everything clears up and then all the control relays reset to zero. I would like to find a different way of clearing this problem, I am still looking for the problem that is causing this. This last time, the e-stop relays would not reset. I looked at the ladders and it seems to get to a certian ladder rung and stop at this line of code. Then none of the control realys internal and e-stops

The PLC will be obeying exactly whatever instructions it is given to operate. You have to start from the belief that the CPU is operating correctly. If you give up that belief then you have nothing to go on!

If we assume that it is working OK, you now have to look through the ladder and investigate exactly why the logic behaves as it does rather than as you expect. Clearly your expectations are wrong here, because the PLC is behaving otherwise. To allow us to help you still requires more details.

Statements like "The enable/rest will not reset" need clarification. Do you mean the contact assigned to the "Enable/Reset" input on the function stays permanently in one logic state, presumably a "1", enabling the SHRB? Or do you mean that it can be moved between "1", enable, and "0", reset, but there appears to be no effect on the contents of the shift register? Let's take the former as the first path of investigation. If a bit won't change state, is it forced? If it is, why? Don't always assume that unforcing it will fix everything - it may reveal another bigger problem that was the reason for the force in the first place! If it's not forced start working through the rest of the ladder to see where this bit may be controled. This has to include direct intentional control as a coil, or inadvertant control due to being part of MWIR instruction or similar. Unfortunately the whole process of debugging a program can be tedious and nit-picking. Keep an open mind and don't make any assumptions.

Post your code, or provide really specific descriptions of the structure, problems, symptoms etc. The TI support here relies heavily on the two Kens, but fortunately I get the impression we both just about know what we're talking about. So far I think we've dug most people out of the holes they've been in.

Regards

Ken

More details required.

Can you give detailed, step by step descriptions of what you've tried? What happened? What didn't happen?
Can you post your program?