SERIES GFM2
GAS MASS FLOW METER
±1% FS, Programmable Relays
The SERIES GFM2 Gas Mass Flow Meters is an ideal choice for the measurement of
flow rates of a wide variety of gases. Unit can be calibrated for a variety of gases with
user selectable 0 to 5 VDC or 4 to 20 mA and two relay outputs and programmable
totalizer that indicates total gas quantity.
FEATURES/BENEFITS
• Utilizes a straight tube sensor with a restrictor flow element to provide a high ±1% FS
accuracy and ±0.25% FS repeatability
• Gas flow can be displayed in 23 different engineering units on an optional 2x16
character LCD display with internal conversion factors for up to 32 gases
• Digital RS-232 or RS-485 interfaces allow for easy communication and for multi-drop
capability of up to 256 units (RS-485 only)
• User-friendly interface allows for the programming of high and low gas flow alarms,
along with two user-programmable electromechanical SPDT relays with latch options
• Stores calibration information for up to 10 different gases, internal or user-specific
K-factors
• Automatic sensor zero offset adjustment (via digital interface or local push button)
• NIST traceable certificate included
• Self-diagnostic tests
APPLICATIONS
• Gas flow measurement
• Gas flow control
• Operating pumps and valves
• Process equipment
• Vacuum processes
• Glass and metal coating
• Film deposition
MODEL CHART
Example GFM2 -AIR
-010 -A -V -A -N -A -2 GFM2-AIR-010-A-V-A-N-A-2
Series
GFM2
Specialty
AIR
Gas &
AR
K-Factor
C2H2
C3H8
C4H10
CH4
CO
CO2
HF
HE
H2
N2
NH3
O2
SO2
Body
010
Size
050
100
Body
A
Material
S
Seal
Material
Fittings
Display
Output
Signal
Digital
Interface
Gas mass flow meter
Air 1.0000
Argon 1.4573
Acetylene 0.5829
Propane 0.3500
Butane 0.2631
Methane 0.7175
Carbon monoxide 1.0000
Carbon dioxide 0.7382
Hydrogen fluoride 0.9998
Helium 1.4540
Hydrogen 1.0106
Nitrogen 1.0000
Ammonia 0.7310
Oxygen 0.9926
Sulfur dioxide 0.6900
Low flow
Medium flow
High flow
Aluminum
Stainless steel: Body size = 010
Body size = 050
Body size = 100
V
Fluoroelastomer
B
Buna-N
E
EPR
T
PTFE
A
1/4˝ compression (low)
B
1/8˝ compression (medium)
D
3/8˝ compression (high)
N
No display
L
LED display
A
0 to 5 VDC
B
4 to 20 mA
2
RS232
5
RS485
9
PROFIBUS
1-1/8
[28.70]
3-5/32 [80.16]
5-5/16 [134.88]
SPECIFICATIONS
Service: Clean gases compatible with wetted parts.
Wetted Materials: GFM2-X-X-A: Anodized aluminum, brass, 316 SS
fluoroelastomer O-rings; GFM2-X-X-S: 316 SS, and fluoroelastomer O-rings;
Buna-N, EPR and PTFE O-rings optional.
Accuracy: ±1% FS.
Repeatability: ±0.25% FS.
Response Time: 2 seconds to within ±2% of actual flow.
Output Signal: Linear 0 to 5 VDC (3000 Ω min. load impedance) and 4 to 20 mA
(500 Ω max. loop resistance).
Relay Rating: 1 A @ 24 VDC.
Max. Particulate Size: 5 microns.
Temperature Limits: 32 to 122°F (0 to 50°C).
Power Supply: 11 to 26 VDC.
Process Connections: 1/8˝ compression fitting for flow rates ≤ 10 L/min; 1/4˝ for ≤
50 L/min; 3/8˝ for ≤ 100 L/min.
Display: 2 x 16 character LCD (optional).
Pressure Limits: 500 psig (34.5 bar).
Leak Integrity: 1 x 10
smL/sec of helium.
-9
Weight: 1.05 lb (0.48 kg).
MAXIMUM FLOW RANGE (l/min)
Body Size AIR AR
010
10
050
50
100
100
MAXIMUM FLOW RANGE (l/min)
Body Size CO
010
5
050
30
100
60
FLOW RANGES
ml/min
l/min
10
2
20
5
50
10
100
20
200
30
500
40
1000
50
60
80
100
Note: Specify flow
range at time of order
ACCESSORIES
Model
Description
A-110NA12 110 VAC power supply, 12 VDC with
communication interface branch
USA: California Proposition 65
WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov
DWYER INSTRUMENTS, INC. | www.dwyer-inst.com
4-29/64
[112.97]
PROCESS CONNECTION
[COMPRESSION FITTINGS ATTACHED]
C
H
C
H
C
H
CH
CO
2
2
3
8
4
10
4
10
5
2
2
5
10
50
20
10
5
30
50
100
50
30
20
60
100
HE
H
N
NH
O
SO
2
2
2
3
2
10
10
10
5
10
5
50
50
50
30
50
30
100
100
100
60
100
60
2
323
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