| 摘要 |
A method is disclosed for determining leakby in a flow controller (100) comprising a flow sensor (102), a flow control valve (106) and electronics (104). The electronics are coupled to the flow sensor, the flow control valve and configured to adjust the flow control valve in response to the signal of the flow sensor indicating the flow rate of the material such that a set flow rate of material through the flow controller is maintained. The steps of the method comprise determining (302) a zero drift (Qdrift) value for the flow sensor (102). Determining (304) a flow rate (Qflow) through the flow controller (100) when the control valve (106) is in the fully closed position. And determining (306) the leakby through the flow controller (100) where the leakby is equal Qflow-Qdrift.
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