Sierra 951 instruction manual Calibration Instructions

CALIBRATION INSTRUCTIONS

Prior to connecting the 951 to the Flowmeter or Controller, verify that the Controller's +/-15 vdc requirement is no more than 400 ma. The 951 is capable of supplying up to 500ma for short periods of time ( in 1/2 or 1 hour increments). Consult the factory if the current requirement is > 350ma for prolonged periods of time.

Connect the 951 to the Flowmeter or Controller or a precision voltage source with an accuracy of 0.01% or better per Figure 3. The voltage source should be connected between J1-1 and J1-2. Apply AC power to the 951. Verify that the 951 lights up and the instrument is displaying a stable reading. If no display appears after 1 or 2 seconds has elapsed, remove the ac power and check the fuse contained in the AC Power Connector at the rear of the 951 (Reference Figure 2 on page 3).

If a stable display appears, allow 15-30 minutes for the 951 to stabilize, then perform the calibration procedure shown below.

1.The FS Cal (CAL) value must be entered prior to performing this calibration procedure. Reference page 8 to enter the FS Cal (CAL) value.

2.Apply zero flow to the Flowmeter, if calibration is done with a Flowmeter, or zero vdc to the 951, if calibration is done with a precision voltage source.

3.Depress and hold CAL (S5) switch for approximately 3 seconds. Verify FS CAL annunciator is extinquished. The 951 is now uncalibrated.

4.Depress and hold the ZERO (S4) switch for approximately 3 seconds (Reference Figure 1 on page 3). Verify ZERO annunciator LED is illuminated and the display reads 0000 +/- 0001 counts. Ignore the decimal point. The 951 is now zeroed.

5.Apply full scale flow to the Flowmeter or 5.000 vdc +/- 0.0005 vdc to the 951.

Page 13