Brooks Instrument GP200 Series, Руководство по установке и эксплуатации

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2. If the MFC was subjected to vacuum purge for more than one
minute, turn off the MFC control valve by giving the device a zero
setpoint and allow a settling period equal to twice the vacuum purge
time.
3. Open the upstream isolation valve and close the downstream
isolation valve to eliminate the pressure drop by isolating the MFC
within the process tool. Ensure the pressure drop across the
MFC control valve is eliminated so that control valve leakage
is not a factor.
4. Send the MFC a 100% FS setpoint for a period of between 30 and
60 seconds to equalize the pressure across its control valve.
5. Shut the upstream isolation valve to prevent any creep effects in
the upstream regulator from affecting the inlet pressure.
6. Send the MFC a zero setpoint command to close the MFC control
valve and wait three minutes.
7. The MFC can now be zeroed.
Zeroing the GP200 Series
Zeroing the GP200 Series from the LCD Display Panel
1. Once all the conditions outlined in the preparation sections
have been met and the pressure across the device is at 0 psid,
press the display button until the %FS can be seen on the
display as shown in Figure 2-5.
Figure 2-5 GP200 Display showing "%FS"
2. Hold the zero button until the display flashes. The display will
continue flashing while the device is zeroing. When the display
stops flashing the zero routine will be complete.
Section 2 Installation
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