HP 5890 II, 5890 II Plus manual 61

Electronic Flow Sensing

Electronic flow sensor (EFS) calibration

Preparation

1.Access the EFS by removing the left side panel; remove two screws along its lower edge, slide the panel toward the rear of the instrument, and then lift.

2.Through the keyboard, select CALIB AND TEST mode, function 2:

CLEAR . 2 ENTER

GAIN A is displayed, followed by two values: the observed flow rate through Channel A, and the current gain calibration value for Channel A.

Setting the zero calibration value

The zero calibration value must be set with no gas flow through the channel being calibrated.

1.Press ZERO : FLOW A ZERO is displayed, followed by a value (the current zero calibration value for EFS Channel A). Note that

Channel A is assumed by default; if channel B is to be calibrated instead, press B .

2.Disconnect the gas source to the particular flow channel being calibrated. Do not trust an on/off valve, pressure regulator, or mass flow controller to be an effective shutoff device; any gas flowing through the EFS will invalidate the zero calibration value. Disconnect the source at any convenient point (e.g., at the connection of the supply line into the instrument).

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