Brooks Instrument GF81 - Manual (Page 29)

2-9
Brooks ® GF40/GF80/GF81 Devices
Installation and Operation Manual
X-TMF-GF40-GF80-Series-MFC-eng
Part Number: 541B161AAG
June, 2013 Section 2 Installation
6. Close the GF40/GF80/GF81 Series and wait two minutes.
7. Read the output signal of the GF40/GF80/GF81 Series in percent of full
scale. This output signal is the initial flow. The output signal should be 0.0
(± 0.1%). If the output signal is too high, re-zero the GF40/GF80/GF81
Series as described in Section 2-16.
2-16 Zeroing the GF40/GF80 Series
1. Allow time for gas pressure to equalize across the MFC's internal control
valve to ensure gas movement.
2. Press and hold down the Zero button, shown in Figure 2-4, for a
minimum of 5 seconds.
Figure 2-4 Zero Button Accessible at Top of Device
Zero button
2-17 Auto Shut-Off
The Auto Shut-off feature closes the GF0xx valve when the set point drops
below 1.5% of full scale. When the Auto Shut-off feature is NOT chosen,
then the GF0xx valve will shut off when the set point drops below 0.5% of
full scale.