The materials included in this compilation are for the use of Dwyer Instruments, Inc. potential customers and current employees as a resource only. They may not be reproduced, published, or transmitted electronically for commercial purposes. Furthermore, the Company’s name, likeness, product names, and logos, included within these compilations may not be used without specific, written prior permission from Dwyer Instruments, Inc. ©Copyright 2014 Dwyer Instruments, Inc.

1. Gas Mass Flowmeters
The materials included in this compilation are for the use of Dwyer Instruments, Inc. potential customers and current employees
as a resource only. They may not be reproduced, published, or transmitted electronically for commercial purposes.
Furthermore, the Company’s name, likeness, product names, and logos, included within these compilations may not be used
without specific, written prior permission from Dwyer Instruments, Inc. ©Copyright 2014 Dwyer Instruments, Inc.

2. Overview
GFM2 – Gas Mass Flowmeter
GFM3 – Gas Mass Flowmeter
Push Button Configuration
GFM4 – Gas Mass Flowmeter
Temperature and Pressure Monitoring

3. GFM2 - Specifications
Service: Clean dry gases
Accuracy: ±1% FS
Temperature Limits: 0 to 50 °C
Power Supply: 11 to 26 VDC
Leak Integrity: 1 x 10-9 ml/sec of He
Flow Ranges: From 10 ml/min to 100 l/min
Calibration: NIST certificate standard

4. GFM2 - Features
Programmable totalizer
Two user-programmable
electromechanical SPDT
relays with latching
option

5. GFM2 - Features
User-selectable analog
0 to 5 VDC or 4 to 20
mA outputs
Internal conversion
factors for up to 32 gases
Digital interface option
RS-232, RS-485, or
Profibus

6. GFM3 - Specifications
Service: Clean dry gases
Accuracy: ±1% FS
Process Temperature Limits: -10 to
50 °C
Power Supply: 12 VDC; 15 VDC, or
±24 VDC
Leak Integrity: 1 x 10-9 ml/sec of He
Flow Ranges: From 10 ml/min to
100 l/min
Calibration: NIST certificate standard

7. GFM3 - Features
Four button keypad and
large LCD with
backlight
Programmable 12 digit
totalizer
Two SPDT relays with
latching option for high
or low alarm outputs

8. GFM3 - Features
Internal conversion
factors for up to 32
gases
Digital interface option
RS-232, RS-485, or
Profibus

9. GFM4 - Specifications
Service: Clean dry gases
Accuracy: ±1% FS
Process Temperature Limits: -10 to
50 °C
Power Supply: 12 VDC; 15 VDC, or
±24 VDC
Leak Integrity: 1 x 10-9 ml/sec of He
Flow Ranges: From 10 ml/min to
100 l/min
Calibration: NIST certificate standard

10. GFM4 - Features
Flow, Pressure, and
Temperature
measurement and output
Four button keypad and
large LCD with
backlight and
programmable 12 digit
totalizer

11. GFM4 - Features
Two SPDT relays with
latching option for high or
low flow or pressure alarm
outputs
Internal conversion
factors for up to 32 gases
Digital interface option
RS-232, RS-485, or
Profibus

12. Flow Scale Options
FLOW RATE
BODY SIZE REQUIRED FOR THE GIVEN GAS
AIR AR C2H2 C3H8 C4H10 CH4 CO CO2 HE HF H2 N2 NH3 O2 SO2
10 ml/min 010 010 010 010 010 010 010 010 010 010 010 010 010 010 010
20 ml/min 010 010 010 010 010 010 010 010 010 010 010 010 010 010 010
50 ml/min 010 010 010 010 010 010 010 010 010 010 010 010 010 010 010
100 ml/min 010 010 010 010 010 010 010 010 010 010 010 010 010 010 010
200 ml/min 010 010 010 010 010 010 010 010 010 010 010 010 010 010 010
500 ml/min 010 010 010 010 010 010 010 010 010 010 010 010 010 010 010
1000 ml/min 010 010 010 010 010 010 010 010 010 010 010 010 010 010 010
2 l/min 010 010 010 010 010 010 010 010 010 010 010 010 010 010 010
5 l/min 010 010 010 050 050 010 010 010 010 010 010 010 010 010 010
10 l/min 010 010 050 050 100 050 010 050 010 010 010 010 050 010 050
20 l/min 050 050 050 100 100 050 050 050 050 050 050 050 050 050 050
30 l/min 050 050 100 100 050 050 050 050 050 050 050 050 050 050
40 l/min 050 050 100 100 050 100 050 050 050 050 100 050 100
50 l/min 050 050 100 100 050 100 050 050 050 050 100 050 100
60 l/min 100 100 100 100 100 100 100 100 100 100 100 100
80 l/min 100 100 100 100 100 100 100 100
100 l/min 100 100 100 100 100 100

13. Applications
Critical flow testing environments such as
analytical laboratories
Used to measure and control gas flow rate into
environmental chambers to provide accurate gas
concentrations

14. Applications
Gas burner metering
Used to measure gas flow rate to burner, and totalize
gas consumption

15. Applications
Widely used in equipment for the
semiconductor industry
Chemical Vapor Deposition
Etching
Backside Wafer Cooling

16. Applications
Semiconductor Industry:
Chemical Vapor Deposition
Precise amounts of precursor gases are flowed into a
reaction chamber to create thin film coatings

17. Applications
Semiconductor Industry:
Wafer Etching
Inert gas flow is used in a high flow purge step
between the wafer etching process and the cleaning
process to limit wafer exposure to moisture or
oxygen

18. Applications
Semiconductor Industry:
Backside wafer cooling
Gases, such as helium, flow across the wafer to
reduce the temperature during processing

19. Applications
Pharmaceutical Industry
Mass flowmeters are used to monitor precise air
flow rates in tablet coating machinery

20. Applications
Pharmaceutical Industry
Mass flowmeters are used to measure the amount of
inert and reactant gases into bioreactors

21. GFM3 – Demonstration
GFM3 with Power and
communication connection cable

22. GFM3 – Demonstration
25 pin connection
for power, outputs,
and communication
Process inlet
connection
Backlit LCD
Display
Process outlet
connection
Product label showing model,
calibrated flow rate and gas,
and serial number
User Interface
Buttons

23. GFM3 – Demonstration
Process value
Calibrated gas
Full scale range
Flow rate units
Totalizer value

24. GFM3 – Demonstration
Display will show some
amount of flow while
warming up

25. GFM3 – Demonstration
Within a few minutes
the flowmeter will settle
at zero

26. GFM3 – Demonstration
Changing Units of Measure
Press to enter the Main Menu
Use the and keys to cycle
through the menu and highlight
sub-menu “Units of Measure”
Press to enter into the sub
menu

27. GFM3 – Demonstration
Changing Units of Measure - Continued
Use the and keys to cycle
through the menu options
Highlight “mL/min” and
press to select this option
Display will return to the Main Menu
and “Current Units: mL/min” will
be displayed at the bottom
Press to exit the main menu

28. GFM3 – Demonstration
Units changes from % to mL/min

29. GFM3 – Demonstration
Configuring the Totalizer
Press to enter the Main Menu
Use the and keys to cycle
through the menu and highlight
sub-menu “Totalizer”
Press to enter into the sub
menu

30. GFM3 – Demonstration
Configuring the Totalizer
Use the and keys to cycle
through the menu options
Highlight “Mode Run/Stop” and
press to select this option
Press once to highlight “Run”
and then press to activate the
totalizer
TOT: S at the bottom of the display
will change to TOT:R to indicate the
totalizer is in run mode

31. GFM3 – Demonstration
Configuring the Totalizer
The “Start at Flow” option is used to
set a minimum flow rate before the
totalizer will start accumulating the
total flow
The “Stop at Total” option is used to
set a maximum limit for the total flow
accumulation
These values are shown at the bottom of
Totalizer menu display for reference

32. GFM3 – Demonstration
Configuring the Totalizer
The totalizer value can be reset
with the “Reset to Zero” option

33. GFM3 – Demonstration
Totalizer