Hello,
We are re-wiring a multi-conveyor system used for educational purposes, and I'd like to run the basic design of the safety circuit/power supply setup by you guys more experienced in panel design/building to see what you think.
The system has one main cabinet with two safety relays, 5 sub-cabinets each with Siemens S7-1500 PLCs and 1x motor control center with 5 VFDs.
There are e-stop buttons at each sub-cabinet and the MCC, an e-stop button at the main cabinet and 2 safety circuits. All e-stop buttons are dual channel and the E-Stops at the sub-cabinets/MCC are wired in series to a safety relay in the main cabinet. Hitting any sub-cabinet/MCC E-Stop button cuts the +24V output power to one group of PLC outputs in each sub-cabinet.
In addition, hitting the E-stop button on the main cabinet cuts all mains power to all sub-cabinets and MCC. This is controlled by the main Safety Relay.
Each safety circuit uses redundant contactors for power switching.
For power to all other components (PLCs, HMIs), each sub-cabinet has its own +24V supply.
Does this method of E-Stop circuit setup sound reasonable? I’m not asking about SIL/etc. level, I just wasn’t sure if running all E-Stop controlled PLC outputs in separate cabinets from a single main supply is common practice, or if it is more common to have separate E-Stop circuits/Safety Relays in each sub-cabinet and use a local supply to power local outputs.
Thanks for the input.
We are re-wiring a multi-conveyor system used for educational purposes, and I'd like to run the basic design of the safety circuit/power supply setup by you guys more experienced in panel design/building to see what you think.
The system has one main cabinet with two safety relays, 5 sub-cabinets each with Siemens S7-1500 PLCs and 1x motor control center with 5 VFDs.
There are e-stop buttons at each sub-cabinet and the MCC, an e-stop button at the main cabinet and 2 safety circuits. All e-stop buttons are dual channel and the E-Stops at the sub-cabinets/MCC are wired in series to a safety relay in the main cabinet. Hitting any sub-cabinet/MCC E-Stop button cuts the +24V output power to one group of PLC outputs in each sub-cabinet.
In addition, hitting the E-stop button on the main cabinet cuts all mains power to all sub-cabinets and MCC. This is controlled by the main Safety Relay.
Each safety circuit uses redundant contactors for power switching.
For power to all other components (PLCs, HMIs), each sub-cabinet has its own +24V supply.
Does this method of E-Stop circuit setup sound reasonable? I’m not asking about SIL/etc. level, I just wasn’t sure if running all E-Stop controlled PLC outputs in separate cabinets from a single main supply is common practice, or if it is more common to have separate E-Stop circuits/Safety Relays in each sub-cabinet and use a local supply to power local outputs.
Thanks for the input.