1756-L62S Safety Task

[Abuuramu]

Hello everyone.

My question is about a safety tasks, the PLC is on fault due to a watchdog time expired. The solution is very simple, download the program or modify the watch dog time of the safety task.
But the PLC does not allow me to download the program, a have been reading about this and i found that the safety task of the PLC is locked and this condition does not allow me to download the program or modify the parameters of the safety task.

the question is how do i unlocked this task?

thanks.

 

[Mike_RH]

Is this a new machine or has it been running for a while?
If it has been running for a while, what is causing the increase in scan time?

 

[Abuuramu]

This machine has been running for a while, about what is causing the increase of the scan time... honestly i do not know.

I have been trying to unlock the safety task but i do not know how to do it.
First i thought that the PLC was locket, but is not.. only the safety task is locket.

Regards

 

[rkukl]

Does you safety application have a password?? If so you will need this to unlock. To unlock right click on controller properties or choose Edit / Properties. Select the safety tab there you will find safety lock/unlock. If there is no password then you should be able to unlock

 

[rkukl]

some screenshots

 

[Mike_RH]

Unlocking the safety task will require regenerating the safety signature. This has legal / liability implications.

 

[Abuuramu]

Thanks for answer.

So... as a resume i will not be able to modify parameters or download the program until the vendor of the machinery send to me the password, right?

some one of you guys have a document or tech note were explain the configuration and management of safety tasks? a have been searching for information but i have not found useful information.

Thanks

 

[jstolaruk]

what makes you think the safety task is responsible for the watchdog fault? Its been a running system and no edits have been made in the safety task, mostly likely its somewhere else.

 

[Timbert]

I wasn't 100% sure but I just tested this. You can download even if the controller is safety locked and a signature has been generated. Provided that the signature and controller match. See table 34 in 1756-UM020 page 112.

It sounds like either your copy of the program doesn't match or there is some other problem.

 

[rkukl]

I use Guard Logix on many machines. The setup of signatures and logic validation is important and must be not ignored. i would suggest reading the manual in the attached link. specifically chapter 6.

http://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1756-rm093_-en-p.pdf