I’m just starting out and don’t quite understand what this diagram specifically means
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Does this diagram show a linkage between temperature and motor current, a linkage between temperature and the pneumatic normally open control valve below, and a linkage between pressure and the pneumatic normally closed shut-off valve above? Also, is the valve next to the pneumatic cut-off valve above a three-way valve or a safety valve?
Find the legend first, and you’ll understand it after studying it
I is not an electric current; it merely represents the logical functions of a program
Isn’t the IIAS below meant to represent the alarm interlock for motor current display?
Well, I can only see the start/stop status; I think AS refers to the air supply
The fault shutdown of the cylinder valve is achieved through logical operation by a solenoid valve, which switches the air path of the cylinder valve. The solenoid valve is controlled by a logical value (a diamond box with the label I), and this logical value is determined by three binary switches: TISA, PISA, and IISA (the specific logic can be found in the interlock logic diagram). The fault-open pneumatic diaphragm control valve below is controlled by TISA. By the way, there is a flaw in this diagram: the fail-open pneumatic diaphragm control valve mentioned below is driven by process air, while the output of TISA is an electrical signal (a switch signal); therefore it cannot directly drive that fail-open pneumatic diaphragm control valve. An electromagnetic valve should be present in the air circuit of such a pneumatic control valve.
Temperature, pressure, and motor current signal alarms trigger interlocks on the valves above; a temperature alarm in turn triggers interlocks on those below
It should be automatic, based on temperature and the speed of the stirring motor； Interlock between pressure and accident relief valve!