Brooks Instrument 5861i - Manual (Page 19)

3-3
Installation and Operation Manual
X-TMF-5861i-MFC-eng
Part Number: 541B111AAG
November, 2008
Brooks ® Model 5861 i
Section 3 Operation
To check zero always mount the flowmeter in its final configuration and
allow a minimum of 20 minutes for the temperature of the controller and its
environment to stabilize. Using a suitable voltmeter check the flowmeter
output signal. If it differs from the factory setting adjust it by removing the
lower pot hold plug, which is located closest to the controller body. Adjust
the zero potentiometer (refer to Figure 3-3) until the desired output signal is
obtained.
3-4 Calibration Procedure
NOTE 1: This calibration procedure is shown using the voltage output (not
current). The conversion accuracy of the voltage to current convertor
allows this with no loss in accuracy using the 4-20 mA output.
NOTE 2: If the mass flowmeter is to be used on a gas other than the
calibration gas, apply the appropriate sensor conversion factor. ( Refer to
Section 4-5).
NOTE 3: Calibration of the Model 5861i mass flowmeter requiresthe use of
a Digital Voltmeter (DVM), and a flow control valve or mass flow controller
to set the flowrate and precision flow standard calibrator such as the Brok
Uol-U-Meter. It is recommended that the calibration be performed only by
trained and qualified service personnel.
a. Adjust the anticipate potentiometer fully clockwise (20 turns). Then
adjust the anticipate potentiometer 10 turns counter clockwise to
center the potentiometer. This will provide a rough adjustment of this
circuit.
b. Connect the DVM positive lead to the 0-5V signal output
(pin 2 D-connector) and the negative lead to circuit common (TP4).
Adjust the zero potentiometer for an output of 0mV ±2mV.
c. Increase the flow rate until the flow signal output equals 5.000V.
Connect the DVM positive lead to TP2 (linearity voltage) and the
negative lead to TP4 (circuit common). Adjust the linearity potenti-
ometer for an output of 0.0V (zero volts).
d. Connect the DVM positive lead to the 0-5V signal output (pin 2 of D-
Connector) and the negative lead to TP4 (circuit common). Adjust
the actual flow rate to within ±2% of desired full scale flow. Measure
the flow rate using suitable volumetric calibration equipmentand
record value. Calculate flow signal voltage with the following for-
mula:
Adjust the span potentiometer (Refer to Figure 3-3) until the 0-5V
signal output equals the flow signal voltage calculated above.
e. Connect the DVM positive lead to TP1 (sensor voltage). The voltage
at TP1 is -100 times the output voltage of the sensor. This voltage
can range from +1.2 to +12 volts, however it is recommended that
this voltage stay between +2.0 to +9.0 volts for proper operation. If
the recommended voltage range exceeds this than the desired
accuracy and/or signal stability may not be achieved. If one of the
limits is reached check the restrictor sizing procedure.
( Refer to Section 4-6).