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What does the LH symbol in the upper right corner of the chain symbol mean in the PID diagram? Please advise! LH is connected together! This post was last edited by Canghaiyili on 2009-4-17 07:56 ]
Is it a separate L or H? Represents low value trigger or high value trigger interlock: lol
The interlocking symbols on the PID diagram should be exactly the instrument graphic symbols. The H, HH, HHH, HHHH on the upper right side of the graphic symbol (circle), and the L, LL, LLL, and LLLL on the lower right side of the graphic symbol (circle) represent high and low alarms. The letters S, A, and Z in the instrument numbers in the circle represent alarm triggering interlocking, alarm output, and parking respectively.
It should mean that the high and low positions alarm at the same time.
I also saw it when looking at our drawings. On the drawing, the interlock goes to LH. It should be the interlock of the lock hopper part, which is program-controlled. When the interlock stops in the coal grinding boundary area, it will connect to GS to mark the interlock of coal grinding.