Best strategy to isolate conveyer for maintenance?

Need advice! We have a powder coat line controlled by 4 DL06's networked together. Each unit controls a segment of the process, the conveyor, the ovens, the dry off fans, etc. We need to do some maintenance on the conveyor. However the system is not programmed to allow the conveyor to run by itself. When the line starts, everything starts.

We are trying to find the simplest way to control the conveyor, without complex changes to our current program if possible. Some ideas we had:


- Write a simple program to control the conveyor, replace the production program on the main plc, perform the maintenance and then revert the program.


- Engage the conveyor manually from the motor controller during the maintenance.



What would you guys recommend? Let me know what other information I can provide to help. Thank you for your knowledge!

Man-Off-Auto selector switch? Manual is hardwired to starter.

I would look at the program for the interface signals.
once you find them (there should be at least 2, one for run, one for stop) and also a signal to the other systems.


remove the signals to the conveyor plc.
remove the signals to the other plc's
jumper the required I/o to get the conveyor running.


BUT !
there may not be a start / stop signal to the conveyor.
can you use the manual controls?


james

In short LOTO ( Lock Out Tag Out) it’s not only a s good idea but it also the law down here in the states
Any person working on a conveyor must have their LOTO on the motor disconnect.
If you don’t the fines could be very large and if somebody gets hurt the fine could be over $100K
I have seen fines like that for companies that violate it.
If the conveyors need to be interlocked for normal use if you lock out one conveyor to work on it, the interlocked conveyors will also stop that’s the way it should work. But please keep in mind that the interlocked conveyors are still operational.
The plc code should interlock the conveyors and provide an orderly startup and shutdown.

GaryS said:

In short LOTO ( Lock Out Tag Out) it’s not only a s good idea but it also the law down here in the states
Any person working on a conveyor must have their LOTO on the motor disconnect.
If you don’t the fines could be very large and if somebody gets hurt the fine could be over $100K
I have seen fines like that for companies that violate it.
If the conveyors need to be interlocked for normal use if you lock out one conveyor to work on it, the interlocked conveyors will also stop that’s the way it should work. But please keep in mind that the interlocked conveyors are still operational.
The plc code should interlock the conveyors and provide an orderly startup and shutdown.

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100% agree with the above post. I just expected this to already be installed on the conveyors. Maybe be sure to have disconnect AUX contacts feeding back to PLC input indicating its state.

Power the line down and just use an external source to drive the conveyor motor, whether it be a DOL or spare drive, depending on what you have to hand or how fast or slow you want it to run.