The situation of motor shutdown in sis
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The device is equipped with a tank; in SIS, the motor stops when the liquid level in the tank falls below 10%. Normally, when there is liquid in the tank, the motor is turned on to pump it out; when the liquid level drops below 10%, the pump motor stops automatically. On the motor control panel on site, there are options for local and remote operation. When the button is set to local mode, liquid level signals are sent when the level in the tank is high; but does the motor keep running when the tank’s liquid level is below 10%? Please share your thoughts, thank you
In a SIS system, whether it is on-site or remotely, the motor will stop when the liquid level drops below 10%. The SIS system does not allow manual intervention.
If setting it to an in-place SIS doesn’t work, then doing so constitutes a violation of the rules.
It probably won’t stop. The so-called local and remote controls on the operation column are actually knob switches for manual and automatic mode switching. It only takes effect when the automatic interlock is activated; it should function similar to a bypass switch. Whether on-site or remotely, the stop button on the control column has the same highest level of authority as the emergency stop button on the SIS auxiliary console – pressing it stops the system immediately. Movable equipment must be capable of being started on-site for testing before operation. Therefore, when the unit is on site, the motor will not stop if the liquid level is below the interlock value.
It probably won’t stop. The so-called local and remote controls on the operation column are actually knob switches for manual and automatic mode switching. It only takes effect when the automatic interlock is activated; it should function similar to a bypass switch. Whether on-site or remotely, the stop button on the control column has the same highest level of authority as the emergency stop button on the SIS auxiliary console – pressing it stops the system immediately. Movable equipment must be capable of being started on-site for testing before operation. Therefore, when the unit is on site, the motor will not stop if the liquid level is below the interlock value.
Interlocks can also be removed; special cases need to be dealt with as well
A bypass has been added to the SIF circuit; this should have an impact when performing SIL verification, right?
For this, you need to examine the electrical schematic of the motor to see whether local/remote operation is intended for a DCS system. Generally, SIS system designs do not take into account local or remote operation; such systems are usually connected to the main circuit of the electrical secondary circuit. It’s similar to an emergency stop function – once it activates, the secondary circuit loses power. Therefore, you need to understand how the instruments work, and for that you must look at the electrical drawings.
It won’t stop; remote/local functions serve as a switching switch for interlock