What do you do if you find a programming error in DCS or PLC sequence after long time of commissioning?

The next start up and be sure there are one we must control manually  ,up date and reboot again if not we have to change the responsible pool .

Long Time of commissioning. That is what confusing!

Well DCS have the facility to modify the programming during the running/execution. You can modify the program without any problem. Whereas, in PLC we have to reprogram and then restart it, whenever possible.

Just to get the point where rectification is required, plan the job and make it correct. Thats it

Simple answer

Correct it

It is the duty of an engineer to report and where possible to correct any errors.

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actually we dont have any option if their is error in program and we cant oprate manually due to lots of I/O. so we need upload programm from controlller and made it error free. so only we can able to oprate the process.

Believe it or not it is not strange to find mistakes it program even after long time from commissioning. Take ur time to carefully check the program and modify it appropriately

first of all you have to raise site query describing the error and through the management of change process the error can be evaluated, corrected and followed.

If we encounter Sequence error in PLC program first need to identify which type of error it is?1. The error generated due to worng feedback from feild instrument?2. In which step sequence is stoping? after getting this ingormation we can go ahead with problem solving.

Trace out the file where the error has occured, For example, if it is a control drawing file in DCS , trace out the file from ur message. Create a new file with the same name, rewrite the logics using function blocks or ladder logics or diagrams, Overwrite the old file with the new one where the Project files are stored. Then give an offline download & once u have checked it go for an online download. 

            I recommend u always keep a back up for all ur files once it works so it would be easy for restoring it in future.

Just restart cpu instantly.

Simply, you have to confirm the required to modify this specific error, if the correction required to be done offline then you have to wait until next shuldown, or may not required offline which you can corrected online.