Dwyer GFM4 User Manual

Series GFM3/4 Digital Mass Flow Meter

Installation and Operating Instructions

Bulletin F-GFM3/4

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A. Fax: [phone] e-mail: [e-mail]

Phone: [phone] www.dwyer-inst.com

ABLE OF CONTENTS

T

. Unpacking the GFM3 Flow Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

1

.1 Inspect Package for External Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

1

1.2 Unpack the Mass Flow Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

1.3 Returning Merchandise for Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

. Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

2

.1 Primary Gas Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

2

.2 Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

2

.2.1 Power Supply Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

2

2.2.2 Output Signal Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

2.2.3 Output Communication Parameters and Connections . . . . . . . . . . .1

. Principle of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

3

. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

4

5. Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

5.1 Preparation and Warm Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

5.2 Swamping Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

.3 Programming GFM3 using LCD and Keypad . . . . . . . . . . . . . . . . . . . . . . .1

5

.3.1 Changing Units of Measurement for Temperature &

5

ressure Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

P

5.3.2 Monitoring DFM Peripheries Settings . . . . . . . . . . . . . . . . . . . . . . . .1

5.3.3 GFM3 Main Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

5.3.4 Gas Flow Engineering Units Settings . . . . . . . . . . . . . . . . . . . . . . . .1

5.3.5 Gas Table Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

.3.6 Totalizer Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

5

.3.7 Alarm Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

5

.3.8 Relay Assignment Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

5

5.3.9 K-Factors Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

5.3.10 Zero Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

5.3.11 Flow Conditions Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

5.3.12 LCD Backlit Energy-Saving Setting . . . . . . . . . . . . . . . . . . . . . . . . .1

5.4 Flow, Temperature, Pressure Output Signals Configuration . . . . . . . . . . .1

. Calibration Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

7

.1 Flow Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

7

.2 Gas Flow Calibration of GFM3 Mass Flow Meters . . . . . . . . . . . . . . . . . .1

7

.2.1 Connections and Initial Warm Up . . . . . . . . . . . . . . . . . . . . . . . . . . .1

7

7.2.2 ZERO Check/Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

7.2.3 Gas Linearization Table Adjustment . . . . . . . . . . . . . . . . . . . . . . . . .1

7.3 Analog Output Calibration of GFM3 Mass Flow Meters . . . . . . . . . . . . . . .1

.3.1 Initial Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

7

.3.2 Gas Flow 0 to 5 Vdc Analog Output Calibration . . . . . . . . . . . . . . . .1

7

.3.3 Gas Flow 4 to 20 mA Analog Output Calibration . . . . . . . . . . . . . . . .1

7

.3.4 Gas Temperature 0 to 5 Vdc Analog

7

Output Calibration (GFM3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

7.3.5 Gas Temperature 4 to 20 mA Analog

Output Calibration (GFM3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

.3.6 Gas Pressure 0 to 5 Vdc Analog

7

utput Calibration (GFM3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

O

.3.7 Gas pressure 4-20 mA Analog

7

Output Calibration (GFM3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

7.4 Temperature and/or Pressure Sensor Calibration . . . . . . . . . . . . . . . . . . .1

8. RS-485/RS-232 Software Interface Commands . . . . . . . . . . . . . . . . . . . . . . .1

.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

8

.2 Commands Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

8

.3 ASCII Commands Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

8

9. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

9.1 Common Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

9.2 Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

.3 Technical Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

9

0. Calibration Conversions from Reference Gases . . . . . . . . . . . . . . . . . . . .1

1

Appendix I GFM3 EEPROM Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Appendix II Internal User Selectable Gas Factor Table

(Internal “K” Factors) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

6. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

6.2 Flow Path Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

6.2.1 Restrictor Flow Element (RFE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

6.2.2 GFM3 Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

6.2.3 GFM3 Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Appendix III Gas Factor Table (“K” Factors) . . . . . . . . . . . . . . . . . . . . . . .1

Appendix IV Component Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Appendix V Dimensional Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Appendix VI Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Page 2

. UNPACKING THE GFM3/4 MASS FLOW METER

1

.1 - Inspect Package for External Damage

1

our GFM3/4 Mass Flow Meter was carefully packed in a sturdy cardboard carton,

Y
with anti-static cushioning materials to withstand shipping shock. Upon receipt,
inspect the package for possible external damage. In case of external damage to
the package contact the shipping company immediately.

.2 - Unpack the Mass Flow Meter

1

pen the carton carefully from the top and inspect for any sign of concealed

O

hipping damage. In addition to contacting the shipping carrier, please forward a

s
copy of any damage report to your distributor or Dwyer Instruments, Inc

.

directly.
When unpacking the instrument please make sure that you have all the items
indicated on the Packing List. Please report any shortages promptly.

.3 - Maintenance/Repair

1

pon final installation of the Series GFM3/4, no routine maintenance is required.

U
The Series GFM3/4 is not field serviceable and should be returned if repair is
needed. Field repair should not be attempted and may void warranty.

Warranty/Return

efer to “Terms and Conditions of Sales” in our catalog and on our website. Contact

R

ustomer service to receive a Return Goods Authorization number before shipping

c

he product back for repair. Be sure to include a brief description of the problem

t
plus any additional application notes

2. INSTALLATION

2.1 - Primary Gas Connections

lease note that the GFM3/4 Mass Flow Meter will not operate with liquids. Only

P

lean gases are allowed to be introduced into the instrument. If gases are

c

ontaminated they must be filtered to prevent the introduction of impediments into

c
the sensor.

AUTION

C

application. For more information, contact your distributor or Dwyer

GFM3/4 transducers should not be used for monitoring
OXYGEN gas unless specifically cleaned and prepared for such

®

Instruments,

Inc.

Attitude limit of Mass Flow Meter is ±15deg from calibration position (standard
calibration is in horizontal position). This means that the gas flow path of the Flow
Meter must be within this limit in order to maintain the original calibration accuracy.
Should there be need for a different orientation of the meter, re-calibration may be
necessary. It is also preferable to install the GFM3/4 transducer in a stable
environment, free of frequent and sudden temperature changes, high moisture, and
drafts.

Prior to connecting gas lines, inspect all parts of the piping system including
ferrules and fittings for dust or other contaminants. Be sure to observe the direction
of gas flow as indicated by the arrow on the front of the meter when connecting the
gas system to be monitored. Insert tubing into the compression fittings until the
ends of the properly sized tubing home flush against the shoulders of the fittings.
Compression fittings are to be tightened according to the manufacturer's
instructions to one and one quarter turns. Avoid over tightening which will seriously
damage the Restrictor Flow Elements (RFE's)!

WARNING

For models GFM4 (Multi Parameter versions) the maximum

pressure in the gas line should not exceed 100 PSIA
(6.8 bars). Applying pressure above 100 PSIA (6.8 bars) for extended periods of
time will seriously damage the pressure sensor and may cause serious injury or
death. Burst pressure is 200 PSIA (13.6 bar)!

GFM3 transducers are supplied with standard 1/4˝ or 3/8˝, or optional 1/8˝ inlet and
outlet compression fittings which should not be removed unless the meter is being
cleaned or calibrated for a new flow range.

Using a Helium Leak Detector, or other equivalent method, perform a thorough
leak test of the entire system. (All GFM3/4’s are checked prior to shipment for
leakage within stated limits. See specifications in this manual.)

2.2 - Electrical Connections

GFM3/4 is supplied with a 25-pin "D" connector. Pin diagram is presented in figure b-

1.

2.2.1 - Power Supply Connections

GFM3/4 transducers are supplied for three different power supply options:

±15Vdc (bipolar power supply)

DC Power (+) --------------- pin 1 of the 25-pin "D" connector
DC Power Common --------------- pin 18 of the 25-pin "D" connector
DC Power (-) --------------- pin 14 of the 25-pin "D" connector

12Vdc or +24Vdc (unipolar power supply)

+

CAUTION

dc! (See power requirements label at the rear of the GFM3/4 meter)

V

.2.2 - Output Signals Connections

2

C

C Power (+) --------------- pin 1 of the 25-pin "D" connector

D

C Power (-) --------------- pin 18 of the 25-pin "D" connector

D

O NOT CONNECT 24 Vdc POWER SUPPLY UNLESS YOUR

D

FM3/4 METER WAS ORDERED AND CONFIGURED FOR 24

G

AUTION

When connecting the load to the output terminals, do not
exceed the rated values shown in the specifications. Failure to

do so might cause damage to this device. Be sure to check that the wiring and

he polarity of the power supply is correct before turning the power ON. Wiring

t

rror may cause damage or faulty operation.

e

FM3/4 Mass Flow Meters are equipped with either calibrated 0 to 5 VDC (0 to 10

G

DC optional) or calibrated 4 to 20 mA output signals (jumper selectable). This

V

inear output signal represents 0 to 100% of the flow meter's full-scale range. Multi

l
Parameter versions (GFM3/4) are in addition equipped with either a calibrated 0 to
5 VDC (0 to 10 VDC optional) or a calibrated 4 to 20 mA output signal (jumper
selectable) for pressure and temperature. Pressure linear output signal represents
0 to 100 PSIA (46.9 kPa). Temperature linear output signal represents 0 to 50

CAUTION

utput signals!

o

All 4 to 20 mA current loop outputs are self-powered (non-

solated). Do not connect an external voltage source to the

i

°

C.

Flow 0 to 5 VDC or 4 to 20 mA output signal connection:

Plus (+) ------------------- pin 2 of the 25-pin "D" connector
Minus (-) ------------------- pin 15 of the 25-pin "D" connector

emperature 0 to 5 VDC or 4 to 20 mA output signal connection

T

lus (+) -------------------- pin 3 of the 25-pin "D" connector

P
Minus (-) -------------------- pin 16 of the 25-pin "D" connector

Pressure 0 to 5 VDC or 4 to 20 mA output signal connection

Plus (+) -------------------- pin 4 of the 25-pin "D" connector
Minus (-) -------------------- pin 17 of the 25-pin "D" connector

To eliminate the possibility of noise interference, use a separate cable entry for the
DC power and signal lines.

2.2.3 - Communication Parameters and Connections

The digital interface operates via RS485 (optional RS-232 is available), and
provides access to applicable internal data including: flow, temperature, pressure
reading, auto zero, totalizer and alarm settings, gas table, conversion factors and
engineering units selection, dynamic response compensation and linearization
table adjustment.

Communication Settings:

Baud rate: -------- 9600 baud
Stop bit: -------- 1
Data bits: -------- 8
Parity: -------- None
Flow Control: -------- None

RS-485 Communication Interface Connection:

The RS485 converter/adapter has to be configured for: multidrop, 2-wire, half
duplex mode. The transmitter circuit has to be enabled by TD or RTS (depending
on which is available on the converter/adapter). Settings for the receiver circuit
usually should follow the selection made for the transmitter circuit in order to
eliminate echo.

RS-485 T(-) or R(-) -------- pin 11 of the 25-pin "D" connector (-)
RS-485 T(+) or R(+) -------- pin 24 of the 25-pin "D" connector (+)
RS-485 GND (if available) -------- pin 20 of the 25-pin "D" connector (GND)

RS-232 Communication Interface Connection:

Crossover connection has to be established:

RS-232 RX
(pin 2 on the DB9 connector) -------- pin 11 of the 25-pin "D" connector (TX)
RS-232 TX
(pin 3 on the DB9 connector) -------- pin 24 of the 25-pin "D" connector (RX)
RS-232 GND
(pin 5 on the DB9 connector) -------- pin 20 of the 25-pin "D" connector (GND)

Page 3

IN FUNCTION

P

+15 Vdc (Optional +12 or +24 Vdc) Power Supply

1

0 to 5 Vdc or 4 to 20 mA Flow Signal Output

2
3 0 to 5 Vdc or 4 to 20 mA Temperature Signal

Output (Optional)

4 0 to 5 Vdc or 4 to 20 mA Pressure Signal

utput (Optional)

O

(reserved)

5

(reserved)

6

(reserved)

7
8 Relay No. 1 - Common Contact
9 Relay No. 1 - Normally Open Contact
10 Relay No. 2 - Normally Closed Contact

1 RS485 (-) (Optional RS232 TX)

1

2 (No Connection)

1

3 Common

1
14 -15 VDC Power Supply (Only for ±15Vdc option)
15 Common, Signal Ground For Pin 2

(4 to 20 mA return)

16 Common, Signal Ground For Pin 3

4 to 20 mA return)

(

7 Common, Signal Ground For Pin 4

1

4 to 20 mA return)

(

18 Common, Power Supply (- DC power for

12 and 24 Vdc)
19 Common
20 RS232 Signal GND (RS-485 GND Optional)

1 Relay No. 1 - Normally Closed Contact

2

2 Relay No. 2 - Common Contact

2

3 Relay No. 2 - Normally Open Contact

2
24 RS485 (+) (Optional RS232 RX)
25 Chassis Ground

NOTICE

In general, "D" Connector numbering patterns are

Figure b-1, GFM3/4 Pin "D"

onnector Configuration

C

standardized. There are, however, some connectors with
nonconforming patterns and the numbering sequence on your mating
connector may or may not coincide with the numbering sequence shown in our
pin configuration table above. It is imperative that you match the appropriate wires
in accordance with the correct sequence regardless of then particular numbers
displayed on the mating connector.

NOTICE

Make sure power is OFF when connecting or disconnecting

any cables in the system.

The (+) and (-) power inputs are each protected by a 400 mA M (medium time-lag)
resettable fuse. If a shorting condition or polarity reversal occurs, the fuse will cut
power to the flow transducer circuit. Disconnect the power to the unit, remove the
faulty condition, and reconnect the power. The fuse will reset once the faulty
condition has been removed. DC Power cable length may not exceed 9.5´ (3
meters).

he flow rate can be displayed in volumetric flow or mass flow engineering units for

T

tandard or actual (temperature, pressure) conditions. Flow meters can be

s

rogrammed locally via the four button keypad and LCD, or remotely, via the RS-

p

32/RS-485 interface. GFM3/4 flow meters support various functions including:

2
flow totalizer, flow, temperature, pressure alarms, automatic zero adjustment, 2
SPDT relays output, 0 to 5 Vdc / 0 to 10 Vdc / 4 to 20 mA analog outputs for flow,
pressure and temperature.

. SPECIFICATIONS

4

FM3

G

ervice: Clean gases compatible with wetted parts.

S
Wetted Materials: 316 SS, 416 SS; Fluoroelastomer, Buna-N, EPR or PTFE O-

rings.

Accuracy: ±1% FS.

epeatability: ±0.25% FS.

R

esponse Time: 0.6 to 1.0 s to within ±2% of setpoint over 20 to 100% FS.

R

utput Signal: Linear 0 to 5 VDC (3000 Ω min. load impedance); 0 to 10 VDC

O

(6000 Ω min. load impedance); 4 to 20 mA (500 Ω max. loop resistance).

Max. Particulate Size: 5 microns.
Temperature Limits: Ambient: 32 to 122°F (0 to 50°C); Dry Gases: 14 to 122°F (-

10 to 50°C).

ower Supply: ±12 VDC; ±15 VDC; ±24 VDC.

P

rocess Connections: 1/8˝ compression fitting for flow rates ≤ 10 L/min; 1/4˝ for ≤

P

0 L/min; 3/8˝ for ≤ 100 L/min.

5

Pressure Limits: 500 psi (35 bar).
Leak Integrity: 1 x 10

-9

smL/sec of helium.

Display: 128 x 64 graphic LCD with backlight.

FM4

G

ervice: Clean gases compatible with wetted parts.

S

etted Materials: 316 SS, 416 SS; Fluoroelastomer, Buna-N, EPR or PTFE O-

W

rings.

Accuracy: ±1% FS.
Repeatability: ±0.25% FS.
Response Time: 0.6 to 1.0 s to within ±2% of setpoint over 20 to 100% FS.
Output Signal: Linear 0 to 5 VDC (3000 Ω min. load impedance); 0 to 10 VDC

(6000 Ω min. load impedance); 4 to 20 mA (500 Ω max. loop resistance).

Max. Particulate Size: 5 microns.
Temperature Limits: Ambient: 32 to 122°F (0 to 50°C); Dry Gases: 14 to 122°F (-

10 to 50°C).

Power Supply: ±12 VDC; ±15 VDC; ±24 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.

Pressure Limits: 200 psia (13.79 barA).
Leak Integrity: 1 x 10

-9

smL/sec of helium.

Display: 128 x 64 graphic LCD with backlight.

Use of the GFM3/4 flow transducer in a manner other than that specified in this
manual or in writing from Dwyer

®

Instruments, Inc, may impair the protection

provided by the equipment.

3. PRINCIPLE OF OPERATION

The stream of gas entering the Mass Flow transducer is split by shunting a small
portion of the flow through a capillary stainless steel sensor tube. The remainder of
the gas flows through the primary flow conduit. The geometry of the primary conduit
and the sensor tube are designed to ensure laminar flow in each branch. According
to principles of fluid dynamics, the flow rates of a gas in the two laminar flow
conduits are proportional to one another. Therefore, the flow rates measured in the
sensor tube are directly proportional to the total flow through the transducer. In
order to sense the flow in the sensor tube, heat flux is introduced at two sections of
the sensor tube by means of precision wound heater sensor coils. Heat is
transferred through the thin wall of the sensor tube to the gas flowing inside. As gas
flow takes place heat is carried by the gas stream from the upstream coil to the
downstream coil windings. The resultant temperature dependent resistance
differential is detected by the electronic control circuit. The measured gradient at
the sensor windings is linearly proportional to the instantaneous rate of flow taking
place. An output signal is generated that is a function of the amount of heat carried
by the gases to indicate mass molecular based flow rates. Additionally, the GFM3/4
model Mass Flow Meter incorporates a Digital Signal Processor (DSP) and non­volatile memory that stores all hardware specific variables and up to 10 different
calibration tables. Multi parameter flow meters provide accurate data on three
different fluid parameters:

• flow

• pressure

• temperature

Page 4

Flow rates are stated for Nitrogen at STP conditions [i.e. 70°F (21.1°C) at 1

*

tm]. For other gases use the K factor as a multiplier from APPENDIX 2.

a

low Rate

odel

M

std liters/min)

(
GFM3/4-X-010
GFM3/4-X-050
GFM3/4-X-100

T

. OPERATING INSTRUCTIONS

5

F

p to 10

u

0

5

100

able IV - Pressure Drops

aximum Pressure Drop

M

(mm H

0)

(psid)

2

25

0.04

200

2

500

5

.23

3

.08

8

(kPa)

0.276

2.3

2

5.7

5

5.1 - Preparation and Warm Up

It is assumed that the Digital Mass Flow Meter has been correctly installed and

horoughly leak tested as described in section 2. Make sure the flow source is OFF.

t

hen applying power to a flow meter, within the first two seconds you will see on

W

he LCD display: the product name, the software version, and revision of the

t
EEPROM table. After two seconds the LSD display switches to the main screen
with the following information:

• Temperature and Pressure reading (for models GFM4 only).
Mass Flow reading in current engineering units.

•
Current Gas Table and Gas Name.

•
Totalizer Volume reading in current volume based engineering units.

•

• Totalizer , Alarm, and Relays status.

¡

F

GFM3/4 Main Screen

NOTICE

Allow the Digital Mass Flow Meter to warm-up for a minimum of
15 minutes.

During initial powering of the GFM3/4 transducer, the flow output signal will be
indicating a higher than usual output. This is an indication that the GFM3/4
transducer has not yet attained its minimum operating temperature. This condition
will automatically cancel within a few minutes and the transducer should eventually
zero.

5.2 - Swamping Condition

If a flow of more than 10% above the maximum flow rate of the Mass Flow Meter
is taking place, a condition known as "swamping" may occur. Readings of a
"swamped" meter cannot be assumed to be either accurate or linear. Flow must
be restored to below 110% of maximum meter range. Once flow rates are lowered
to within calibrated range, the swamping condition will end. Operation of the meter
above 110% of maximum calibrated flow may increase recovery time. -

5.3 - Programming GFM3/4 using LCD and Keypad

All features of the flow meter can be accessed via the local four button keypad and
LCD. The LCD incorporates an energy-saving auto shut-off backlit feature. If
enabled, after 15 minutes of operation without user intervention the LCD backlight
turns off. In order to turn on the LCD backlight press any key on the keypad. The
LCD backlight energy-saving auto shut-off feature can be disabled or enabled by
user (see p. 5.3.12 "LCD backlight Energy-saving Setting").

.3.1 - Changing Units of Measurement for Temperature and Pressure

5

eading

R

y default after power up, the temperature reading is displayed in °F and pressure

B

n PSI. Pressing ( ) [Enter] button from main screen will alter the units of measure

i
to °C for temperature and kPa for pressure reading respectively. In order to change
units of measure back to °F for temperature and PSI for pressure, press ( )
[Enter] button while in the main screen one more time.

.3.2 - Monitoring GFM3/4 Peripheries Settings

5

he last row at the bottom of the main LCD screen reflects settings and status for

T
Totalizer, Flow Alarm, and Relays (see Figure b-2).

¡

F

igure B-2

F

Totalizer Status:

TOT: R - totalizer is running (Enabled).
TOT: S - totalizer is stopped (Disabled).

low Alarm Status:

F

: S - flow alarm is disabled.

A
A: R,N - flow alarm is enabled and currently there are no alarm conditions.
A: R,L - flow alarm is enabled and currently there is Low alarm condition.
A: R,H - flow alarm is enabled and currently there is High alarm condition.

Relay Settings:

N - No assignment (relay is not assigned to any events).
H - High Flow Alarm condition.
L - Low Flow Alarm condition.
R - Range between High and Low Flow Alarm condition.
T - Totalizer reached set limit.
A - High Temperature Alarm condition.
B - Low Temperature Alarm condition.
C - High Pressure Alarm condition.
D - Low Pressure Alarm condition.

Continued pressing of the ( ) [Up] button from the main screen will switch the
status line to display the following information:

- Calibrated full-scale range in standard L/min for current Gas Table.

- Device Digital Communication interface type (RS-485 or RS-232).

- Device RS-485 address (two hexadecimal characters).

- Device Zero DAC counts (for troubleshooting purposes).

- Device Sensor Average ADC counts (for troubleshooting purposes).

- Device Sensor Compensated ADC counts (for troubleshooting purposes).

NOTICE

Pressing the ( ) [Dn] button from any of the status line will

switch the status display to one step back.

Page 5

5.3.3 - GFM3/4 Main Menu

Pressing of the ( ) [Esc] button from the main screen will switch the display to the

ain Menu. The following screen will appear:

M

i

If the User defined Unit of Measure option is selected the following screen will
appear:

igure b-5, User Defined Unit of Measure Screen (K factor)

F

Figure b-3, GFM3/4 Main Menu Screen

ressing of the ( ) [Up] or ( ) [Dn] buttons allows the user to scroll up or down

P

he menu options. Press ( ) [Enter] button to select the highlighted option of the

t

enu.

m

The following menu options are available:

1. Units of Measure - View or Change the Units of Measure for Flow process

ariable.

v

. Gas Table Select - View or Change the Gas Table.

2

. Totalizer - View or Change settings for Totalizer.

3

4. Alarm Settings - View or Change settings for Flow, Pressure and Temperature

larm.

A

. Relay Action - View or Change settings for each of two available Relays.

5

6. K Factors - View or Change settings for User defined or Internal K Factors.

7. Zero Calibration - Initiate Automatic Sensor Zero Calibration.

8. Flow Conditions - Allows the user to set the Actual or Standard Flow conditions.

9. BackLight Timer - Allows the user to turn On/Off the Energy-saving for LCD

acklight.

b

10.Exit - Returns to the Main Screen with process variables reading.

NOTICE

5.3.4 Gas Flow Engineering Units Settings

While in the Main Menu scroll with ( ) [Up] or ( ) [Dn] button to highlight the
Units of Measure option and press the ( ) [Enter] button. The following screen will
appear.

Pressing the ( ) [Esc] button from any level of the Menu will
switch the menu to one level higher (up to Main Screen).

Figure b-4, GFM3/4 Units of Measure Screen

In order to specify the User Defined Unit of Measure user has to set three key
parameters:

factor - Conversion factor relative to L/min unit of measure.

K

ime base - Hours, Minutes, or Seconds.

T
Density - Use density (YES / NO).

Press the ( ) [Enter] button to move the flashing cursor to the digit that has to be
adjusted. Pressing ( ) or ( ) will increment or decrement a particular digit

espectively. The numbers will change from 0 to 9 and next to the decimal point (.).

r

ressing the ( ) button one more time will change the digit on the highlighted

P

osition of the cursor back to 0. The same is true in reverse when pressing the

p
( ) button. Only one decimal point is allowed. If changing position of the decimal

oint is required, change decimal point to any desired digit then move the cursor to

p

he required position and adjust it to the decimal point with ( ) or ( ) button. When

t
complete with K-factor value settings, press the ( ) [Esc] button to move in to the
Time base settings screen. The following screen will appear:

Figure b-6, User Defined Unit of Measure Screen (Time base)

Use ( ) or ( ) buttons to highlight desired time base option. Press the ( ) [Enter]
button to set the Time base and move in to the density settings screen. The
following screen will appear:

i

The following Engineering Units menu options are available:

1. % FS - percent of full-scale.

2. L/min - Liters per minute.

3. L/h - Liters per hour.

4. mL/min - milliliters per minute.

5. mL/h - milliliters per hour.

6. SCFH - cubic feet per hour.

7. SCFM - cubic feet per minute.

8. LbPH - pounds per hour.

9. LbPM - pounds per minute.

10. User - User defined Unit of Measure.

11. Exit - Exit to Main Menu

Selecting option 1 to 9 sets the corresponding Unit of Measure and switches the
LCD back to Main Menu.

NOTICE

Once Flow Unit of Measure is changed the Totalizer's Volume
based Unit of Measure will be changed automatically.

Figure b-7, User Defined Unit of Measure Screen (Density)

Use ( ) or ( ) button to highlight desired density option. Press the ( ) [Enter]
button when done. The LCD will display the Units of Measure Screen and new
settings will be reflected at the bottom status line.

5.3.5 - Gas Table Settings

The GFM3/4 Mass Flow Meter is capable to store calibration data for up to 10
different gases.

NOTICE

ordered). If instead of the valid Gas Name (for example NITROGEN) the main
creen displays Gas designator as "Uncalibrated", then the user has chosen the
gas table which was not calibrated. Using an Uncalibrated Gas Table will result in
erroneous reading.

Page 6

By default the GFM3/4 is shipped with at least one valid
calibration table (unless optional additional calibrations were

rom the Main Menu, the user would traverse the menu tree until reaching the "Gas

F

able Select" menu. The following screen will appear:

T

se ( ) or ( ) button to highlight "Start at Flow" option and press the ( ) [Enter]

U

utton. The following screen will appear:

b

’

Figure b-8, Current Gas Table Settings

se ( ) or ( ) button to select desired Gas Table, and press the ( ) [Enter]

U

utton. The LCD will display the Main Menu screen. If desired, press the ( ) [Esc]

b
button to go back to the Main GFM3/4 screen. The new gas table number and the
name of the gas will be reflected on the Main GFM3/4 screen.

5.3.6 - Totalizer Settings

he total volume of the gas is calculated by integrating the actual gas flow rate with

T

espect to time. Both keypad menu and digital interface commands are provided to:

r

• Set the totalizer to ZERO.

• Start the totalizer at a preset flow.

• Assign action at a preset total volume.
Start/stop (enable/disable) totalizing the flow.

•
Read totalizer.

•

The totalizer has several attributes which may be configured by the user. These
attributes control the conditions which cause the totalizer to start integrating the gas
flow, and also specify actions to be taken when the Total Volume is outside the
specified limit.

NOTICE

entered in %FS engineering unit. Totalizer will not totalize until the flow rate
becomes equal or more than the Totalizer Start value. Totalizer Stop values have to
be entered in volume / mass based engineering units.

Totalizer action conditions become true when the totalizer reading and preset "Stop
at Total" volumes are equal.

From the Main Menu, the user would traverse the menu tree until reaching the
"Totalizer" menu. The following screen will appear:

Before enabling the Totalizer, ensure that all totalizer settings
are configured properly. Totalizer Start values have to be

Figure b-11, Totalizer Settings (Start)

ressing ( ) or ( ) will increment or decrement Start Flow value per 0.1% FS

P

espectively. When done with adjustment, press the ( ) [Enter] button.

r

Use ( ) or ( ) button to highlight "Stop at Total" option and press the ( ) [Enter]
button. The following screen will appear.

:

Figure b-12, Totalizer Settings (Stop)

Press the ( ) [Enter] button to move the flashing cursor to the digit that has to be
adjusted. Pressing ( ) or ( ) will increment or decrement a particular digit
respectively. The numbers will change from 0 to 9. Pressing the ( ) button one
more time will change the digit on the highlighted position of the cursor back to 0.
The same is true in reverse,when pressing the ( ) button. Only one decimal point
is allowed. If changing position of the decimal point is required, change decimal
point to any desired digit then move the cursor to the required position and adjust
it to the decimal point with ( ) or ( ) button. When done with adjustment, press
the ( ) [Esc] button.

5.3.7 - Alarm Settings

GFM3/4 provides the user a flexible alarm/warning system that monitors the
Process Variables (Gas Flow, Pressure and Temperature) for conditions that
fall outside configurable limits, and then provides feedback to the user visually
via the LCD (only for Flow) or via a Relay contact closure.

Figure b-9, Totalizer Settings

Mode Run/Stop - Allows the user to Enable/Disable Totalizer.
Start at Flow - Allows the user to enter Gas flow rate in %FS at which Totalizer

starts integrating of the gas flow.

Stop at Total - Allows the user to enter Totalizer Limit Volume when user defined

action will occur.

Reset to Zero - Allows the user to reset Totalizer reading to zero.

Use ( ) or ( ) button to highlight "Mode Run/Stop" option and press the ( )
[Enter] button. The following screen will appear:

’

Figure b-10, Totalizer Settings (Stop/Run)

There are three different alarms:

• Gas Flow - (GFM 3/4)

• Gas Temperature - (GFM4)

• Gas Pressure - (GFM4)

Each alarm has several attributes which may be configured by the user. These
attributes control the conditions which cause the alarm to occur, and also specify
actions to be taken when the Process Variable is outside the specified conditions.

NOTICE

conditions.

From the Main Menu, the user would traverse the menu tree until reaching the
"Alarm Settings" menu. The following screen will appear:

Page 7

All three alarms are non-latching. That means the alarm is
indicated only while the monitored value exceeds the specified

Figure b-13, Alarm Settings

se ( ) or ( ) button to highlight "Flow Alarm" option and press the ( ) [Enter]

U

utton. The following screen will appear:

b

igure b-14, Flow Alarm Settings

F

ode Run/Stop - Allows the user to Enable/Disable Flow Alarm.

M
Low Alarm - The value of the monitored Flow in % FS below which is considered

an alarm condition.

NOTICE

igh Alarm - The value of the monitored Flow in % FS above which is considered

H

n alarm condition.

a

NOTICE

Action Delay - The time in seconds that the Flow rate value must remain above

he high limit or below the low limit before an alarm condition is indicated. Valid

t

ettings are in the range from 0 to 3600 seconds.

s

NOTICE

The user can enable and configure Temperature and Pressure Alarms via the
similar menu:

Main Menu " Alarm Settings " Temp. Alarms - For Temperature Alarm
Main Menu " Alarm Settings " Pres. Alarms - For Pressure Alarm

NOTICE

to be entered in the currently set engineering units: PSI or kPa (absolute).

P (absolute) = P (gauge) + P (atmospheric)

5.3.8 - Relay Assignment Settings

Two sets of dry contact relay outputs are provided to actuate user supplied
equipment. These are programmable via local keypad or digital interface, such that
the relays can be made to switch when a specified event occurs (e.g. when a low
or high flow, pressure or temperature alarm limit is exceeded, or when the totalizer
reaches a specified value).

he value of the Low Alarm has to be less then the value of

T

he High Alarm.

t

he value of the High Alarm has to be more then the value of

T

he Low Alarm.

t

f the alarm condition is detected, and the Relay is assigned to

I
Alarm event, then the corresponding Relay will be energized.

High and Low limits for the Temperature Alarm have to be
entered in °C. High and Low limits for the Pressure Alarm have

he user selects a Relay by scrolling up/down the list of available Relays until the

T

esired Relay is highlighted and then presses the ( ) [Enter] button. The following

d

creen will appear:

s

i

igure b-16, Relay #1 Action Settings

F

he user can configure the Relay action from 9 different options:

T

No Action : (N) No assignment (relay is not assigned to any events).
Totalizer > Limit : (T) Totalizer reached set limit volume.
High Flow Alarm : (H) High Flow Alarm condition.

ow Flow Alarm : (L) Low Flow Alarm condition.

L

ange between H&L : (R) Range between High and Low Flow Alarm condition.

R

igh Temp. Alarm : (A) High Temperature Alarm condition.

H
Low Temp. Alarm : (B) Low Temperature Alarm condition.
High Pres. Alarm : (C) High Pressure Alarm condition.
Low Pres. Alarm : (D) Low Pressure Alarm condition.
Exit

he user selects an Action by scrolling up/down the list of available options until the

T

esired option is highlighted and then presses the ( ) [Enter] button.

d

5.3.9 K - Factors Settings

Conversion factors relative to Nitrogen for up to 32 gases are stored in the GFM3/4
(see APPENDIX II). In addition, provision is made for a user defined conversion
factor. Conversion factors may be applied to any of the ten gas calibrations via
keypad or digital interface commands.

The available K Factor settings are:

• Disabled - (K = 1).

• Internal Index - The index [0-31] from internal K factor table (see APPENDIX II).

• User Defined - User defined conversion factor.

NOTICE

From the Main Menu, the user would traverse the menu tree until reaching the "K
Factors" menu. The following screen will appear:

The conversion factors will not be applied for % FS engineering
unit.

From the Main Menu, the user would traverse the menu tree until reaching the
"Relay Action" menu. The following screen will appear:

Figure b-15, Relay Assignment Screen

Figure b-17, K Factors Screen

The user selects a K factor by scrolling up/down the list of available options until
the desired option is highlighted and then presses ( ) [Enter] button. For Internal
Index and User Defined options, user will be prompted to enter desired index/value
of conversion factor.

5.3.10 - Zero Calibration

The GFM3/4 includes an auto zero function that when activated, automatically
adjusts the mass flow sensor to read zero. The initial zero adjustment for your
GFM3/4 was performed at the factory. It is not required to perform zero calibration
unless the device has zero reading offset with no flow conditions.

NOTICE

condition is established.

Page 8

Before performing Zero Calibration, make sure the device is
powered up for at least 30 minutes and absolute no flow

hut off the flow of gas into the Digital Mass Flow Meter. To ensure that no seepage

S

r leak occurs into the meter, it is good practice to temporarily disconnect the gas

o

ource. From the Main Menu, the user would traverse the menu tree until reaching

s

he "Zero Calibration" menu. The following screen will appear:

t

igure b-18, Zero Calibration (Start)

F

The user must acknowledge the warning that the Auto Zero procedure is about to
be started and there is absolutely zero flow thru the meter. Selecting YES confirms
that user has taken the necessary precautions and starts Auto Zero algorithm.
Selecting NO aborts the Auto Zero procedure.

o start Auto Zero use ( ) or ( ) button to highlight "Yes" option and press the

T

) [Enter] button. The following screen will appear:

(

here:

W

a = Actual gas temperature measured by the GFM3/4 in units of degrees Celsius

T

a = Actual absolute pressure measured by the GFM3/4 in units of PSI

P

NOTICE

he Actual Flow reading will not be calculated for %FS

T

ngineering unit.

e

In order to select Standard or Actual flow measurement, user would traverse the

enu tree until reaching the "Flow Conditions" menu. The following screen will

m

ppear:

a

igure b-21, Flow Condition Screen

F

se ( ) or ( ) button to highlight desired option and press the ( ) [Enter] button.

U

5.3.12 - LCD Backlight Energy-Saving Setting

The GFM3/4's LCD incorporates Energy-saving auto shut-off backlight feature. If
enabled, after 15 minutes of operation without user intervention, the LCD backlit

urns off. In order to turn on LCD backlight, press any key on the keypad. In order

t

o enable/disable Energy-saving auto shut-off backlight feature, user would

t

raverse the menu tree until reaching the "Back Light Timer" menu. The following

t
screen will appear:

Figure b-19, Zero Calibration (In progress)

The Auto Zero procedure normally takes 2 to 3 minutes during which Zero and
Sensor reading will be changed approximately every 4 seconds. The nominal value
for fully balanced sensor is 120 counts. If the GFM3/4's digital signal processor was
able to adjust the Sensor reading within 120 ±2 counts, then Auto Zero is
considered as successful and the screen below will appear:

Figure b-20, Zero Calibration (Completed)

If the device was unable to adjust Sensor reading to within 120 ± 2 counts, then
Auto Zero is considered as unsuccessful and user will be prompted with "Auto Zero
is Failed!" screen.

5.3.11 - Flow Conditions Settings

For GFM3/4 models, the flow reading can be displayed for standard or actual
conditions (Temperature / Pressure adjusted). Since mass flow sensors are
sensitive to changes in gas density and gas velocity, all mass flow meters indicate
flow rates with reference to a set of standard conditions. For Dwyer

®

Instruments,
Inc. standard conditions are defined as 21.1°C (70°F) and 101.3 kPa (14.7 psia).
Other manufacturers may use different values. Standard flow rate is the flow rate
the gas would be moving if the temperature and pressure were at standard
conditions. It is usually the most convenient measure of the gas flow because it
defines the heat-carrying capacity of the air. Actual (volumetric) flow rate is the true
volume flow of the gas exiting the flow meter. In some instances, actual (volumetric)
flow rate rather than standard flow rate may be of interest. To display actual
(volumetric) flow rate, the GFM4 will multiply the standard flow measurement by the
following density correction factor:

Figure b-22, LCD Backlight Energy-Saving Screen

Use ( ) or ( ) button to highlight desired option and press the ( ) [Enter] button.

5.4 - Flow, Temperature, Pressure output Signals Configuration

GFM3/4 Mass Flow Meters are equipped with calibrated 0 to 5 Vdc (0 to 10 Vdc
optional) and 4 to 20 mA output signals. The set of the jumpers (J2, J3, J4) on
the analog printed circuit board is used to switch between 0 to 5 Vdc, 0 to 10 Vdc
or 4 to 20 mA output signals (see Table VI).

NOTICE

GFM3 models are equipped with gas flow rate output signal
only. GFM4 models in addition provide output signals for

temperature and pressure

Analog output signals of 0 to 5 Vdc, (0 to 10 Vdc optional) or 4 to 20 mA are
attained at the appropriate pins of the 25-pin "D" connector (see Figure b-1) on the
side of the GFM3/4 transducer.

Page 9

nalog Signal

A

low Rate Output

F

umper Header J2

J

Temperature Output

Jumper Header J3

ressure Output

P
umper Header J4

J

able VI Analog Output Jumper Configuration

T

ee APPENDIX IV for actual jumpers layout on the analog PCB.

S

0 to 5 VDC

J2.A

5 to 9

J2.B

2 to 6

J2.C

7 to 11

2.D

to 12

J

8

3.A

to 9

J

5

3.B

to 6

J

2

3.C

to 11

J

7

J3.D

8 to 12

J4.A

5 to 9

J4.B

2 to 6

4.C

to 11

J

7

4.D

to 12

J

8

0 to 10 VDC 4 to 20 mA

J2.A

J2.A
J2.B
J2.C

2.D

J

3.A

J

3.B

J

3.C

J
J3.D
J4.A
J4.B

4.C

J

4.D

J

5 to 9
2 to 6
7 to 11

to 12

8

to 9

5

to 6

2

to 11

7
8 to 12
5 to 9
2 to 6

to 11

7

to 12

8

J2.B
J2.C

2.D

J

3.A

J

3.B

J

3.C

J
J3.D
J4.A
J4.B

4.C

J

4.D

J

1 to 5
2 to 6
3 to 7

to 8

4

to 5

1

to 6

2

to 7

3
4 to 8
1 to 5
2 to 6

to 7

3

to 8

4

6. MAINTENANCE

6.1 - Introduction

It is important that the Mass Flow Meter is used with clean, filtered gases only.

iquids may not be metered. Since the RTD sensor consists, in part, of a small

L

apillary stainless steel tube, it is prone to occlusion due to impediments or gas

c

rystallization. Other flow passages are also easily obstructed. Therefore, great

c
care must be exercised to avoid the introduction of any potential flow impediment.
To protect the instrument, a 50 micron (10 L/min) or 60 micron (50 to 100 L/min)
filter is built into the inlet of the flow transducer. The filter screen and the flow paths
may require occasional cleaning as described below. There is no other

ecommended maintenance required. It is good practice however, to keep the

r

eter away from vibration, hot or corrosive environments, and excessive RF or

m

agnetic interference. If periodic calibrations are required, they should be

m
performed by qualified personnel and calibrating instruments, as described in
section 7. It is recommended that units are returned to Dwyer

®

Instruments, Inc. for

repair service and calibration.

WARNING

TO PROTECT SERVICING PERSONNEL IT IS MANDATORY

THAT ANY INSTRUMENT BEING SERVICED IS
COMPLETELY PURGED AND NEUTRALIZED OF TOXIC, BACTERIOLOGICALLY
INFECTED, CORROSIVE OR RADIOACTIVE CONTENTS.

6.2 - Flow Path Cleaning

Before attempting any disassembly of the unit for cleaning, try inspecting the flow
paths by looking into the inlet and outlet ends of the meter for any debris that may
be clogging the flow through the meter. Remove debris as necessary. If the flow
path is clogged, proceed with steps below.

Do not attempt to disassemble the sensor. If blockage of the sensor tube is not
alleviated by flushing through with cleaning fluids, please return meter for servicing.

NOTICE

DISASSEMBLY MAY COMPROMISE CURRENT

CALIBRATION.

6.2.1 - Restrictor Flow Element (RFE)

The Restrictor Flow Element (RFE) is a precision flow divider inside the transducer
that splits the inlet gas flow by a preset amount to the sensor and main flow paths.
The particular RFE used in a given Mass Flow Meter depends on the gas and flow
range of the instrument.

6.2.2 - 10 L/min Models

Unscrew the inlet compression fitting of meter. Note that the Restrictor Flow
Element (RFE) is connected to the inlet fitting. Carefully disassemble the RFE from
the inlet connection. The 50 micron filter screen will now become visible. Push the
screen out through the inlet fitting. Clean or replace each of the removed parts as
necessary. If alcohol is used for cleaning, allow time for drying. Inspect the flow
path inside the transducer for any visible signs of contaminant. If necessary, flush
the flow path through with alcohol. Thoroughly dry the flow paths by flowing clean
dry gas through. Carefully re-install the RFE and inlet fitting, avoiding any twisting
and deforming the RFE. Be sure that no dust has collected on the O-ring seal.

NOTICE

OVER TIGHTENING WILL DEFORM AND RENDER THE RFE

DEFECTIVE. IT IS ADVISABLE THAT AT LEAST ONE
CALIBRATION POINT BE CHECKED AFTER RE-INSTALLING THE INLET
FITTING.

6.2.3 - 50 to 100 L/min Models

Unscrew the four socket head cap screws (two 10-24 and two 6-32) at the inlet side
of the meter. This will release the short square block containing the inlet
compression fitting. The 60 micron filter screen will now become visible. Remove
the screen. DO NOT remove the RFE inside the flow transducer! Clean or replace
each of the removed parts as necessary. If alcohol is used for cleaning, allow time
for drying. Inspect the flow path inside the transducer for any visible signs of
contaminants. If necessary, flush the flow path through with alcohol. Thoroughly dry
the flow paths by flowing clean dry gas through. Re-install the inlet parts and filter

creen. Be sure that no dust has collected on the O-ring seal. It is advisable that at

s

east one calibration point be checked after re-installing the inlet fitting - see section

l

.

7

7. CALIBRATION PROCEDURES

OTICE

N

REMOVAL OF THE FACTORY INSTALLED CALIBRATION
SEALS AND/OR ANY ADJUSTMENTS MADE TO THE

ETER, AS DESCRIBED IN THIS SECTION, WILL VOID ANY CALIBRATION

M

ARRANTY APPLICABLE.

W

.1 - Flow Calibration

7

®

Dwyer

Instruments, Inc. Flow Calibration Laboratory offers professional calibration
support for Mass Flow Meters, using precision calibrators under strictly controlled
conditions. NIST traceable calibrations are available. Calibrations can also be

erformed at customers' sites using available standards. Factory calibrations are

p

erformed using NIST traceable precision volumetric calibrators incorporating liquid

p

ealed frictionless actuators. Generally, calibrations are performed using dry

s
nitrogen gas. The calibration can then be corrected to the appropriate gas desired
based on relative correction [K] factors shown in the gas factor table (see
APPENDIX III). A reference gas, other than nitrogen, may be used to better
approximate the flow characteristics of certain gases. This practice is recommended

hen a reference gas is found with thermodynamic properties similar to the actual

w

as under consideration. The appropriate relative correction factor should be

g

ecalculated (see section 9). It is standard practice to calibrate Mass Flow Meters

r
with dry nitrogen gas at 70.0°F (21.1°C), 20 psia (137.9 kPa absolute) inlet pressure
and 0 psig outlet pressure. It is best to calibrate GFM3/4 transducers to actual
operating conditions. Specific gas calibrations of non-toxic and non-corrosive gases
are available at specific conditions. Please contact your distributor or Dwyer

nstruments, Inc. for a price quotation.

I

t is recommended that a flow calibrator of at least four times better collective

I
accuracy than that of the Mass Flow Meter to be calibrated be used. Equipment
required for calibration includes: a flow calibration standard, PC with available RS­485/RS-232 communication interface, a certified high sensitivity multi meter (for
analog output calibration only), an insulated (plastic) screwdriver, a flow regulator
(for example - metering needle valve) installed upstream from the Mass Flow
Meter, and a pressure regulated source of dry filtered nitrogen gas (or other
suitable reference gas). It is recommended to use Dwyer

®

supplied calibration and maintenance software to simplify the calibration process.
Gas and ambient temperature, as well as inlet and outlet pressure conditions
should be set up in accordance with actual operating conditions.

7.2 - Gas Flow Calibration of GFM3/4 Mass Flow Meters

NOTICE

All adjustments in this section are made from the outside of the

meter via digital communication interface between a PC
(terminal) and GFM3/4. There is no need to disassemble any part of the instrument
or perform internal PCB component (potentiometers) adjustment.

GFM3/4 Mass Flow Meters may be field recalibrated/checked for the same range
they were originally factory calibrated for. When linearity adjustment is needed, or
flow range changes are being made, proceed to step 7.2.3. Flow range changes
may require a different Restrictor Flow Element (RFE). Consult your distributor or

®

Dwyer

Instruments, Inc. for more information.

7.2.1 - Connections and Initial Warm Up

Power up the Mass Flow Meter for at least 30 minutes prior to commencing the
calibration procedure. Establish digital RS-485/RS-232 communication between
PC (communication terminal) and the GFM3/4. Start Dwyer
supplied calibration and maintenance software on the PC.

7.2.2 - ZERO Check/Adjustment

Check SENSOR AVERAGE counts on the GFM3/4 LCD status line. Keep pressing
the ( ) [Up] button from the main screen until status line will display Device Sensor
Average ADC counts. With no flow conditions, the sensor Average reading must be
in the range 120 10 counts. If it is not, perform Auto Zero procedure (see section

5.3.10 "Zero Calibration").

7.2.3 - Gas Linearization Table Adjustment

NOTICE

Your GFM3/4 Digital Mass Flow Meter was calibrated at the

factory for the specified gas and full-scale flow range (see
device front label). There is no need to adjust the gas linearization table unless
linearity adjustment is needed, flow range has to be changed, or new additional
calibration is required. Any alteration of the gas linearization table will void
calibration warranty supplied with instrument!

Gas flow calibration parameters are stored in the Gas Dependent portion of the
EEPROM memory separately for each of 10 calibration tables. See APPENDIX I for
complete list of gas dependent variables.

Page 10

Instruments, Inc.

®

Instruments, Inc.

®

NOTICE

ake sure the correct gas number and name is selected as

M
current on the main GFM3/4 screen. All adjustments made to

the gas linearization table will be applied to the currently selected gas.

The GFM3/4 gas flow calibration involves building of the table of the actual flow
values (indexes 114, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134) and
corresponding sensor readings (indexes 113, 115, 117, 118, 119, 121, 123, 125,

27, 129, 131, 133). Actual flow values are entered in normalized fraction format:

1

00.000 % FS corresponds to 1.000000 flow value, and 0.000 % FS corresponds

1

o 0.000000 flow value. The valid range for flow values is from 0.000000 to

t

.000000 (note: GFM3/4 will accept up to 6 digits after decimal point). Sensor

1
readings are entered in counts of 12 bits ADC output and should always be in the
range of 0 to 4095. There are 11 elements in the table, so the data should be
obtained at increment 10.0 % of full-scale (0.0, 10.0, 20.0, 30.0, 40.0, 50.0, 60.0,

0.0, 80.0, 90.0 and 100.0 % FS).

7

NOTICE

o not alter memory index 113 (must be 120 counts) and 114

D

(must be 0.0). These numbers represent zero flow calibration

point and should not be changed.

If a new gas table is going to be created, it is recommended to start calibration from
100% full-scale. If only linearity adjustment is required, calibration can be started in

ny intermediate portion of the gas table. Using the flow regulator, adjust the flow

a

ate to 100% of full-scale flow. Check the flow rate indicated against the flow

r

alibrator. Observe flow reading on the GFM3/4. If the difference between calibrator

c
and GFM3/4 flow reading is more than 0.5% FS, make a correction in the sensor
reading in the corresponding position of the linearization table (Index 133). If the
GFM3/4 flow reading is more than the calibrator reading, the number of counts in
the index 133 has to be decreased. If the GFM3/4 flow reading is less than the

alibrator reading, the number of counts in the index 133 has to be increased. Once

c

ndex 133 is adjusted with a new value, check the GFM3/4 flow rate against the

I

alibrator and if required, perform additional adjustments for Index 133. If a simple

c
communication terminal is used for communication with the GFM3/4, then "MW"
(Memory Write) command from the software interface commands set may be used
to adjust sensor value in the linearization table (see section 8.3 for complete
software interface commands list). Memory Read "MR" command can be used to
read the current value of the index. Assuming the GFM3/4 is configured with RS­485 interface and has address "11", the following example will first read the existing
value of Index 133 and then write a new adjusted value:

AS TEMPERATURE

G

empOutScaleV - DAC 0 to 5/0 to 10 Analog Output Scale for Temperature

T

empOutScale_mA - DAC 4 to 20mA Analog Output Scale for Temperature

T

TempOutOffset_mA - DAC 4 to 20mA Analog Output Offset for Temperature

AS PRESSURE

G

resOutScaleV - DAC 0 to 5/0 to 10 Analog Output Scale for Pressure

P

resOutScale_mA - DAC 4 to 20mA Analog Output Scale for Pressure

P

NOTICE

.3.1 - Initial Setup

7

ower up the Mass Flow Meter for at least 3 minutes prior to commencing the

P

odels GFM3/4 do not support temperature and pressure

M

easurement and have only one gas flow analog output.

m

calibration procedure. Make sure absolutely no flow takes place through the meter.
Establish digital RS-485/RS-232 communication between PC (communication
terminal) and GFM3/4. The commands provided below assume that calibration will
be performed manually (w/o Dwyer

aintenance software) and the device has RS-485 address 11. If Dwyer

m

nstruments, Inc. supplied calibration and maintenance software is used, skip the

I

ext section and follow prompts from the software.

n

®

Instruments, Inc. supplied calibration and

Enter Backdoor mode by typing: !11,MW,1000,1[CR]
Unit will respond with: !11,BackDoorEnabled: Y
Disable DAC update by typing: !11,WRITE,4,D[CR]

nit will respond with: !11,DisableUpdate: D

U

.3.2 - Gas Flow 0 to 5 Vdc Analog Output Calibration

7

1. Install jumpers J2 on the analog PC board for 0-5 Vdc output (see Table VI).

2. Connect a certified high sensitivity multi meter set for the voltage measurement
to the pins 2 (+) and 15 (-) of the 25-pin D connector.

3. Write 4000 counts to the DAC channel 1: !11,WRITE,1,4000[CR].

4. Read voltage with the meter and calculate.

®

!11,MR,133[CR] - reads EEPROM address 133
!11,MW,133,3450[CR] - writes new sensor value (3450 counts) in to the index 133

Once 100% FS calibration is completed, user can proceed with calibration for
another 9 points of the linearization table using the same approach.

NOTICE

It is recommended to use Dwyer®Instruments, Inc. supplied

calibration and maintenance software for gas table calibration.
This software includes an automated calibration procedure which may radically
simplify reading and writing in to the EEPROM linearization table.

7.3 - Analog output Calibration of GFM3/4 Mass Flow Meters

GFM3/4 series Mass Flow Meters are equipped with calibrated 0 to 5 Vdc (0 to 10
Vdc optional) and 4 to 20 mA output signals. The set of the jumpers (J2, J3, J4) on
the analog printed circuit board is used to switch between 0 to 5 Vdc, 0 to 10 Vdc
or 4 to 20 mA output signals (see APPENDIX IV).

NOTICE

All analog outputs available on the GFM3/4 Digital Mass Flow

Meter were calibrated at the factory for the specified gas and
full-scale flow range (see device front label). There is no need to perform analog
output calibration unless the analog PC board was replaced or off set/span
adjustment is needed. Any alteration of the analog output scaling variables in the
Gas independent table will void calibration warranty supplied with instrument!

NOTICE

It is recommended to use the Dwyer®Instruments, Inc. supplied

calibration and maintenance software for analog output
calibration. This software includes an automated calibration procedure which may
radically simplify calculation of the offsets and spans variables and reading and
writing in to the EEPROM table.

The GFM3/4 analog output calibration involves calculation and storing of the offset
and span variables in to the EEPROM for each available output. The 0 to 5 Vdc and
0 to 10 Vdc outputs have only scale variable, and 20 mA outputs have offset and
scale variables. The following is a list of the Gas independent variables used for
analog output computation:

5. Save FlowOutScaleV in to the EEPROM: !11,MW,26,X[CR]
Where: X - the calculated FlowOutScaleV value.

7.3.3 - Gas flow 4 to 20 mA analog output calibration

1. Install jumpers J2 on the analog PC board for 4 to 20 mA output (see Table VI).

2. Connect a certified high sensitivity multi meter set for the current measurement

to pins 2 (+) and 15 (-) of the 25 pins D connector.

3. Write 4000 counts to the DAC channel 1: !11,WRITE,1,4000[CR].

4. Read current with the meter and calculate.

5. Write zero counts to the DAC channel 1: !11,WRITE,1,0CR].

6. Read offset current with the meter and calculate:

7. Save FlowOutScale_mA in to the EEPROM: !11,MW,27,Y[CR].
Save FlowOutOffset_mA in to the EEPROM: !11,MW,28,Z[CR].

Where: Y - the calculated FlowOutScale_mA value.

Z - the calculated FlowOutOffset_mA value.

7.3.4 - Gas Temperature 0 to 5 Vdc Analog Output Calibration (GFM3/4)

1. Install jumpers J3 on the analog PC board for 0 to 5 Vdc output (see Table VI).

2. Connect a certified high sensitivity multi-meter set for the voltage measurement

to the pins 3 (+) and 16 (-) of the 25-pin D connector.

3. Write 4000 counts to the DAC channel 2: !11,WRITE,2,4000[CR].

4. Read voltage with the meter and calculate.

GAS FLOW

FlowOutScaleV - DAC 0 to 5/0 to 10 Analog Output Scale for Flow

FlowOutScale_mA - DAC 4 to 20mA Analog Output Scale for Flow

FlowOutOffset_mA - DAC 4 to 20mA Analog Output Offset for Flow

5. Save TempOutScaleV in to the EEPROM: !11,MW,29,X[CR].

Where: X - the calculated TempOutScaleV value.

Page 11

.3.5 - Gas temperature 4 to 20 mA Analog Output Calibration (GFM4)

7

. Install jumpers J3 on the analog PC board for 4 to 20 mA output (see Table VI).

1

. Connect a certified high sensitivity multi-meter set for the current measurement

2

o the pins 3 (+) and 16 (-) of the 25-pin D connector.

t

3. Write 4000 counts to the DAC channel 2: !11,WRITE,2,4000[CR].

4. Read current with the meter and calculate.

. Write zero counts to the DAC channel 2: !11,WRITE,2,0CR].

5

6. Read offset current with the meter and calculate.

7. Save TempOutScale_mA in to the EEPROM: !11,MW,30,Y[CR].
Save TempOutOffset_mA in to the EEPROM: !11,MW,31,Z[CR].

here: Y - the calculated TempOutScale_mA value.

W

7.3.6 - Gas Pressure 0 to 5 Vdc Analog Output Calibration (GFM3/4)

1. Install jumpers J4 on the analog PC board for 0 to 5 Vdc output (see Table VI).

2. Connect a certified high sensitivity multi-meter set for the voltage measurement

to the pins 4 (+) and 17 (-) of the 25-pin D connector.

. Write 4000 counts to the DAC channel 3: !11,WRITE,3,4000[CR].

3

. Read voltage with the meter and calculate.

4

5. Save PresOutScaleV in to the EEPROM: !11,MW,32,X[CR].
W

.3.7 Gas pressure 4 to 20 mA Analog Output Calibration (GFM4)

7

1. Install jumpers J4 on the analog PC board for 4 to 20 mA output (see Table VI).

2. Connect a certified high sensitivity multi-meter set for the current measurement

to the pins 4 (+) and 17 (-) of the 25-pin D connector.

3. Write 4000 counts to the DAC channel 3: !11,WRITE,3,4000[CR].

4. Read current with the meter and calculate.

- the calculated TempOutOffset_mA value.

Z

here: X - the calculated PresOutScaleV value.

.2 - Commands Structure

8

he structure of the command string:

T

<Addr>,<Cmd>,Arg1,Arg2,Arg3,Arg4<CR>

!

Where:

! Start character **
Addr RS485 device address in the ASCII representation of

md The one or two character command from the table

C

rg1 to Arg4 The command arguments from the table below.

A

CR Carriage Return character.

** Default address for all units is 11. Do not submit start character and two

character hexadecimal device address for RS-232 option.

everal examples of commands follow. All assume that the GFM3/4 has been

S

onfigured for address 15 (0F hex) on the RS485 bus:

c

1. To get the temperature reading: !0F,TR<CR>

The GFM4 will reply: !0F72.5 F<CR> >

. To get the pressure reading: !0F,PR<CR>

2

he GFM4 will reply: !0F14.5 PSI<CR> >

T

3. To get a flow reading: !0F,F<CR>

The GFM3/4 will reply: !0F50.0<CR>

4. Set the high alarm limit to 85% FS: !0F,A,H,85.0<CR>

exadecimal (00 through FF are valid).**

h

elow.

b

Multiple arguments are comma delimited.

Assuming temperature is 72.5F)

(

Assuming pressure is 14.5 PSI)

(

(Assuming the flow is at 50%F.S.)

5. Write zero counts to the DAC channel 3: !11,WRITE,3,0CR].

6. Read offset current with the meter and calculate.

7. Save PresOutScale_mA in to the EEPROM: !11,MW,33,Y[CR].
Save PresOutOffset_mA in to the EEPROM: !11,MW,34,Z[CR].
Where: Y - the calculated PresOutScale_mA value.

Z - the calculated PresOutOffset_mA value.

NOTICE

command below).

Enable DAC update by typing: !11,WRITE,4,N[CR].
Unit will respond with: !11,DisableUpdate: N.

Close Backdoor mode by typing: !11,MW,1000,0[CR].
Unit will respond with: !11,BackDoorEnabled: N.

7.4 - Temperature and/or Pressure Sensor Calibration

Calibration of the temperature and pressure sensors for GFM3/4 devices is not
described in this manual. Temperature or/and pressure sensors re-calibration
requires factory assistance.

8. RS-485/RS-232 SOFTWARE INTERFACE COMMANDS

8.1 - General

The standard GFM3/4 comes with an RS-485 interface. For the optional RS-232
interface, the start character (!) and two hexadecimal characters for the address
have to be omitted. The protocol described below allows for communications with
the unit using either a custom software program or a "dumb terminal." All values
are sent as printable ASCII characters. For RS-485 interface, the start character is
always (!), and the command string is terminated with a carriage return (line feeds
are automatically stripped out by the GFM3/4). See section 2.2.3 for information
regarding communication parameters and cable connections.

When done with the analog output calibration, make sure the
DAC update is enabled and the BackDoor is closed (see

The GFM3/4 will reply: !0FAH85.0<CR>

NOTICE

address is sent, all devices on the RS-485 bus execute the command, but do not
reply with acknowledge message.

The global address can be used to change RS-485 address for a particular device
with unknown address:

1. Make sure only one device (which address has to be changed) is connected to
the RS-485 network.

2.Type the memory write command with global address: !00,MW,7,XX[CR].

Where XX, the new hexadecimal address can be [01 - FF]. After assigning the
new address, a device will accept commands with the new address.

NOTICE

the same address are connected to the one RS-485 network, the bus will be
corrupted and communication errors will occur.

Address 00 is reserved for global addressing. Do not assign
global address for any device. When command with global

Do not assign the same RS-485 address for two or more
devices on the same RS-485 bus. If two or more devices with

Page 12

ommand

C

ame

N

Flow

emperature

T

eading

R

ressure

P
Reading

Gas Select

uto Zero

A

Flow Alarms

Temperature
Alarms**

Pressure
Alarms

Relay Action

Description

Requests the current flow sensor

eading.

r

equests the current temperature

R

ensor reading (** if supported by

s
hardware)
Requests the current pressure
sensor reading (**if supported by

ardware)

h

elects one of the ten primary gas

S

alibration tables to use. Tables are

c

ntered via the MEM commands at

e
time of calibration.
Starts/reads the status of the auto
zero feature (Note: The Z, N

ommand can be used only when

c

bsolutely no flow takes place

a

hrough the meter. It can take

t

everal minutes to complete. Unit

s
will not respond to other commands
when this is in progress.)
Sets/reads the status of gas flow
alarms.
Note: High and Low limits have to
be entered in the % FS. High alarm
value has to be more than Low

larm value.

a

larm conditions:

A

Flow > High Limit = H
Flow < Low Limit = L

Low < Flow < High = N
Sets/reads the status of the
temperature alarms. Note: High
and Low limits have to be entered
in °C. High alarm value has to be
more than Low alarm value.

Alarm conditions:
Temp. > High Limit = H
Temp. > Low Limit = L
Low < Temp. < High = N
(**if supported by hardware)
Sets/reads the status of the
pressure alarms. Note: High and
Low limits have to be entered in
PSI; High alarm value has to be
more than Low alarm value.
Alarm conditions:
Temp. > High Limit = H
Temp. > Low Limit = L
Low < Temp. < High = N
(**if supported by hardware)
Assigns action of the two SPDT
relays. The coil is energized when
the condition specified by
“Argument 2” becomes true.

o.

N

ommand

C

1

F

2

R

T

3

R

P

4

G

5

Z

6

FA

7

TA

8

PA

9

R

rgument 1

A

T (set gas table)

(status)

S

(do it now)

N
W (write zero to
EEPROM)
S (status while

uto zero in

a

rogress)

p

(display zero

V
value)
H (high flow limit)
L (low flow limit)
A (action delay in
seconds)
E (enable alarm)
D (disable alarm)*

(read status)

R

S (read status)

H (high limit)
L (low limit)
E (enable alarm)
D (disable alarm)
R (read status)

S (set status)

H (high limit)
L (low limit)
E (enable alarm)
D (disable alarm)
R (read status)

S (set status)

1 (relay 1)
2 (relay 2)

rgument 2

A

0 (gas 0) to

 (gas 9)

9

<Value>
<Value>
<Value> (0 to
3600 sec)

<Value>

<Value>
<Value>

N (no action,
relay disabled)*
T (totalizer
reading > limit)
H (high flow
alarm)
L (low flow alarm)
R (range high &
low alarm)
A (high temp.)
B (low temp.)
C (high press.)
D (low press.)
S (status)

rgument 3 Argument 4 Response

A

<Value> (Actual flow
in current engineering
units)

Value> (Actual

<

emperature in current

t

ngineering units)

e

Value> (Actual

<
pressure in current
engineering units)
GTO through GT9

SO through GS9

G

gas name>

<

N

Z
ZW (when done)

ZNI,<value>while Z, N

s in progress

i

V, <zero value>

Z

AH<Value>
AL<Value>
AA<Value>

AE
AD

(no alarm)

N

(high alarm)

H

(low alarm)

L
AS:M,L,H,D

TAH<Value>
TAL<Value>
TAE
TAD
N (no alarm)
H (high alarm)
L (low alarm)
TAS:M,L,H

PAH<Value>
PAL<Value>
PAE
PAD
N (no alarm)
H (high alarm)
L (low alarm)

PAS:M,L,H

RN

RT

RH

RL
RR

RA
RB
RC
RD
RxN, RxT, RxH, RxL,
RxR, RxA, RxB, RxD

Page 13

Command
Name

otalizer

T

K Factors

Units

Maintenance
Timer

Full-Scale

Flow
Conditions

Read
Memory
Write
Memory

UART Error Codes:

1 - Back Door is Not Enabled
2 - Wrong Number of Arguments
3 - Hardware for Requested Function is Not Installed (Not Available)
4 - Wrong Number of the Characters in the Argument
5 - Attempt to Alter Write Protected Area in the EEPROM
6 - Proper Command or Argument is not found
7 - Wrong Value of the Argument
8 - Wrong Command
9 - Reserved
10 - Argument Out of Range
11 - Auto ZERO in Progress

Description

ontrols action of the flow totalizer.

C

Applies a gas correction factor to

the currently selected primary gas

alibration table.

c

Note: does not work with % FS

(

ngineering unit)

e

Sets the units of measure for the

flow signal and totalizer.

ote: The units of the totalizer

N

utput are not per unit time.

o

Hours since last time unit was

calibrated

Returns the full-scale rated flow in

L/min. (Note: This term is not

multiplied by the current K factor)

Set STD or ACTUAL flow

conditions

Reads the value in the specified

memory location.

Write the specified value to the

specified memory location. Use

carefully, can cause unit to

malfunction.

No.

10

1

12

13

14

15

16

17

1

Command

T

K

U

C

E

FC

MR

MW

Argument 1

Z (reset to zero)
F (start totalizer at

low & FS)

f

(limit volume in

L

urrent E.U.)

c

(stop the

D
totalizer)
E (run the
totalizer)

(read the

R

otalizer)

t

(setting status)

S

(disable, sets

D
K=1)
I (internal K factor
table index)

(user specified

U

actor)

f
S (status)
%(% full-scale)*
L/min
(liters per min.)

/h

L
(liters per hr.)
mL/min

mililiters per min)

(

L/h

m

mililiters per hr.)

(
CFH (cubic feet
per hour)
CFM (cubic feet
per min.)
LBPH (pounds per
min.)
UD (user defined)

S<status> Returns
current flow EU.
R (read timer)
C (set timer to
zero)

T - STD
A - ACTUAL
S - Status
0000 to 999
(table index)
0000 to 999
(table index)

Argument 2

<value>

gas flow %FS)

(

value>

<

gas volume)

(

<value>index
from internal

able [0-31]

t

value> (decimal

<

orrection factor)

c

<value>
(conversion factor
from SLPM)

Argument 3

S - seconds
M - minutes
H - hours
(time base)

Argument 4

Y - use density
N - do not use
density

Response

TZ
TF<value>

L<value>

T

D

T

TE

value>

<

S:M, Start, Limit

T

D

K

KI<value>
<value> = [0-31]

U<value>

K

K<value>
U%
UL/min

L/h

U

UmL/min

mL/h

U

UCFH

UCFM

ULBPH
ULBPM
UUD<value>,<value>,
<value>

U<value>
<value>
CC

<value>

FC STD
FC ACTUAL
FC STD
<value>

MWXXX<value>
XXX = Table Index

Page 14

. TROUBLESHOOTING

9

.1 - Common Conditions

9

our GFM3/4 Digital Mass Flow Meter was thoroughly checked at numerous quality

Y

ontrol points during and after manufacturing and assembly operations. It was

c
calibrated according to your desired flow and pressure conditions for a given gas
or a mixture of gases. It was carefully packed to prevent damage during shipment.
Should you feel that the instrument is not functioning properly, please check for the

ollowing common conditions first:

f

Are all cables connected correctly?

•
Are there any leaks in the installation?

•
Is the power supply correctly selected according to requirements?

•

• When several meters are used, a power supply with appropriate current rating

should be selected.

• Were the connector pinouts matched properly?
When interchanging with other manufacturers' equipment, cables and

•

onnectors must be carefully wired for correct pin configurations.

c

Is the pressure differential across the instrument sufficient?

•

No.

Indication

1

o zero reading after 15 min. warm up time and

N

o flow condition.

n

2

CD display remains blank when unit is powered

L
up. No response when flow is introduced from
analog outputs 0 to 5 Vdc or 4 to 20 mA.

3

LCD display reading and/or analog output 0 to 5

dc signal fluctuate in wide range during flow

V
measurement.

4

LCD display reading does correspond to the
correct flow range, but 0 to 5 Vdc output signal
does not change (always the same reading or
around zero).

5

LCD display reading and 0 to 5 Vdc output
voltage do correspond to the correct flow range,
but 4 to 20 mA output signal does not change
(always the same or reading around 4.0 mA).

6

Calibration is off (more than 1.0 % FS).

7

LCD display reading is above maximum flow
range and output voltage 0 to 5 Vdc signal is
more than 5.0 Vdc when gas flows through the
GFM3/4.

8

Gas flows through the GFM3/4, but LCD display
reading and The output voltage 0 to 5 Vdc signal
do not respond to flow.

9

Gas does not flow through the GFM3/4 with inlet
pressure applied to the inlet fitting. LCD display
reading and output voltage 0 to 5 Vdc signal
show zero flow.

10

Gas flows through the GFM3/4, but LCD display
reading is negative and output voltage 0 to 5 Vdc
signal does not respond to flow (reading near
1mV).

11

GFM3/4 is disconnected from the source of the
gas (no flow conditions) but LCD display reading
is fluctuating in wide range. Output voltage 0 to 5
Vdc signal also fluctuating. The power supply
voltage is within specification and stable.

Likely Reason
Embedded temperature has been

hanged.

c

ower supply is bad or polarity is

P

eversed.

r

C board is defective.

P

utput 0 to 5 Vdc signal (pins 2-15, 3-16,

O

-17 of the D-connector) is shorted on

4
the GND or overloaded.
Output 0 to 5 Vdc schematic is burned
out or damaged.
Analog flow output scale and offset
variable are corrupted.
External loop resistance is open or more
than 500 Ω.
Output 4 to 20 mA schematic is burned
out or damaged.
GFM3/4 has initial zero shift.

Sensor under swamping conditions (flow
is more than 10% above maximum flow
rate for particular GFM3/4).
PC board is defective.
The gas flow is too low for particular
model of GFM3/4.
GFM3/4:

RFE is not connected properly to

the inlet fitting.

GFM3/4 models
blocked the sensor.

Sensor or PC board is defective.
Filter screen obstructed at inlet.

Direction of the gas flow is reversed.

GFM3/4 is connected in the installation
with back pressure conditions and gas
leak exist in the system.
Direction of the gas flow is reversed.

GFM3/4 is connected in the installation
with back pressure conditions and gas
leak exist in the system.
Sensor or PC board is defective.

: RFE is shifted and

Page 15

Solution
Perform Auto Zero Procedure (see section 5.3.10 "Zero

alibration").

C

or 12 or 24 Vdc option:

F

easure voltage on pins 1 and 18 of the 25-pin D connector. If

M

oltage is out of specified range, then replace power supply with a

v
new one. If polarity is reversed (reading is negative) make correct
connection.
For ±15Vdc option:
Measure voltage on pins 1-18 and 14-18 of the 25-pin D connector.
If voltage is out of specified range, then replace power supply with
a new one. If polarity is reversed (reading is negative) make correct
connection.

eturn GFM3/4 to factory for repair.

R

heck external connections to pins 2-15, 3-16, 4-17 of the D

C

onnector. Make sure the load resistance is more than 1000 Ω.

c

Return GFM3/4 to factory for repair.

Restore original EEPROM scale and offset variable or perform
analog output recalibration (see section 7.3).
Check external connections to pins 2 and 15 of the D connector.
Make sure the loop resistance is less than 500 Ω.
Return GFM3/4 to factory for repair.

Shut off the flow of gas into the GFM3/4 (ensure gas source is
disconnected and no seepage or leak occurs into the meter).
Wait for 15 min. with no flow condition and perform Auto Zero
calibration Procedure (see section 5.3.10 "Zero Calibration").
Lower the flow through GFM3 within calibrated range or shut down
the flow completely. The swamping condition will end automatically.

Return GFM3/4 to factory for repair.
Check maximum flow range on transducer's front panel and make
required flow adjustment.
Unscrew the inlet compression fitting of the meter and reinstall
RFE (see section 6.2.2). NOTE: Calibration accuracy can be
affected.
Unscrew the four socket head cap screws at the inlet side of the
meter. Reinstall RFE and retaining ring (see section 6.2.3). NOTE:
Calibration accuracy can be affected.
Return GFM3/4 to factory for repair.
Flush clean or disassemble to remove impediments or replace the
filter screen (see section 6.2). NOTE: Calibration accuracy can be
affected.
Check the direction of gas flow as indicated by the arrow on the
front of the meter and make required reconnection in the
installation.
Locate and correct gas leak in the system. If GFM3/4 has internal
leak return it to factory for repair.

Check the direction of gas flow as indicated by the arrow on the
front of the meter and make required reconnection in the
installation.
Locate and correct gas leak in the system.
If GFM3/4 has internal leak return it to factory for repair.

Return GFM3/4 to factory for repair.

.3 - Technical Assistance

9

®

wyer

nstruments, Inc. will provide technical assistance over the phone to

D

I

ualified repair personnel. Please call our Technical Assistance at 219-879-8000.

q

lease have your Serial Number and Model Number ready when you call.

P

10. CALIBRATION CONVERSIONS FROM REFERENCE GASES

The calibration conversion incorporates the K factor. The K factor is derived from

as density and coefficient of specific heat. For diatomic gases:

g

K

as

g

1

=

X C

d

p

where d = gas density (gram/liter)

coefficient of specific heat (cal/gram)

Cp=

ote in the above relationship that d and Cp are usually chosen at standard

N

onditions of one atmosphere and 25°C.

c

®

wyer

FM3/4 EEPROM Variables Rev. A3

D

G

Gas Independent Variables

No.

Indication

0

BlankEEPROM

1

SerialNumber

2

ModelNumber

3

SoftwareVer

4

TimeSinceCalHr

5

ptions1

O

6

eserved2

R

7

ddressRS485

A

8

DogGasNumber

9

FlowUnits

10

AlarmMode

11

LowAlarmPFS

12

HiAlarmPFS

13

AlmDelay

14

RelaySetting[0]

15

RelaySetting[1]

16

TotalMode

17

Total

18

TotalFlowStart

19

TotalVolStop

20

KfactorIndex

21

UserDefKfactor

22

UDUnitKfactor

23

UDUnitTimeBase

24

UDUnitDensity

25

TPUnits

26

FlowOutScaleV

27

FlowOutScale_mA

28

FlowOutOffset_mA

29

TempOutScaleV

30

TempOutScale_mA

31

TempOutOffset_mA

32

PresOutScaleV

33

PresOutScale_mA

34

PresOutOffset_mA

35

TAInScaleV

36

TAInOffsetV

37

PAInScaleV

38

PAInOffsetV

39

SensorZero

40

Klag [0]

41

Klag [1]

42

Klag [2]

43

Klag [3]

44

Klag [4]

45

Klag [5]

46

Reserved

47

Reserved

48

Reserved

49

Reserved

50

Reserved

51

Reserved

52

Kgain [0]

53

Kgain [1]

Data Type

char[10]
char[20]
char[20]
char[10]
float

int

u

har

c

har [3]

c
int
int
char
float
float
uint
char
char
char
float
float
float
int
float
float
int
char
char
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float
float

Notes

Do not modify. Table Revision.
Serial Number
Model Number
Firmware Version
Time since last calibration in hours
M
F
T
Current Gas Table Number [0 - 9]
Current Units of Measure [0 - 10]
Alarm Mode [‘R’ - Enabled, ‘S’ - Disabled]
Low Flow Alarm Setting [%FS] 0 - Disabled
High Flow Alarm Setting [%FS] 0 - Disabled
Flow Alarm Action Delay [0 - 3600 sec] 0 - Disabled
Relay #1 Assignment Setting (N, T, H, L, Range)
Relay #2 Assignment Setting (N, T, H, L, Range)
Totalizer Mode [‘R’ - Enabled, ‘S’ - Disabled]
Totalizer Volume in %*s (updated every 6 min)
Start Totalizer at Flow [%FS] 0 - Disabled
Totalizer Action Limit Volume [%*s] 0 - Disabled
Internal K-Factor Index [0 - 31]**
User Defined K-Factor
K-Factor for User Defined Units of Measure
User Defined Unit Time Base [1, 60, 3600 sec]
User Defined Unit Density Flag [Y, N]
Temperature/Pressure Units [C (Bar), F (PSI)]
DAC 0 to 5/0 to 10 Analog Output Scale for Flow
DAC 4 to 20 mA Analog Output Scale for Flow
DAC 4 to 20 mA Analog Output Scale for Flow
DAC 0 to 5/0 to 10 Analog Output Scale for Temp.
DAC 4 to 20 mA Analog Output Scale for Temp.
DAC 4 to 20 mA Analog Output Scale for Temp.
DAC 0 to 5/0 to 10 Analog Output Scale for Pressure
DAC 4 to 20 mA Analog Output Scale for Pressure
DAC 4 to 20 mA Analog Output Scale for Pressure
ADC Temp. Analog In Scale (0 to 5 V)
ADC Temp. Analog In Offset (0 to 5 V)
ADC Pressure Analog In Scale (0 to 5 V)
ADC Pressure Analog In Offset (0 to 5 V)
D/A Value for Sensor Zero [0 to 4095 counts]
DRC Lag Constant [Do Not Alter]
DRC Lag Constant [Do Not Alter]
DRC Lag Constant [Do Not Alter]
DRC Lag Constant [Do Not Alter]
DRC Lag Constant [Do Not Alter]
DRC Lag Constant [Do Not Alter]

Gain for DRC Lag Constant [Do Not Alter]
Gain for DRC Lag Constant [Do Not Alter]

f the flow range of a Mass Flow Controller or Controller remains unchanged, a

I

elative K factor is used to relate the calibration of the actual gas to the reference

r

as.

g

here Q

w

or example, if we want to know the flow rate of oxygen and wish to calibrate

F

ith nitrogen at 1000 SCCM, the flow rate of oxygen is:

w

Q

= Q

O

a

2

where K = relative K factor to reference gas (oxygen to nitrogen)

PPENDIX I

A

isc. Options*

low Conditions [0-STD, 1-ACTUAL]

wo character adress for RS485

Page 16

Q

K

a

=

K

Q

mass flow rate of an actual gas

=

a

(sccm)

a

=

K

r

r

Qr= mass flow rate of a reference gas

(sccm)

K factor of an actual gas

Ka=

K factor of a reference gas

K

=

r

= Q

x K = 1000 X 0.9926 = 992.6 sccm

r

No.

Indication

54

Kgain [2]

5

5

Kgain [3]

6

5

gain [4]

K

7

5

gain [5]

K

8

5

eserved

R

59

eserved

R

60

Reserved

61

Reserved

2

6

Reserved

3

6

eserved

R

4

6

factorMode

K

5

6

mpAlarmMode

T

66

owAlarmC

L

67

HiAlarmC

68

PrsAlarmMode

9

6

LowAlarmP

0

7

iAlarmP

H

1

7

ero_T

Z

72

cor_K

T

ndex

I

ame

N

100

asIndentifier

G

101

FullScaleRange

102

StdTemp

103

StdPressure

04

1

StdDensity

05

1

alibrationGas

C

106

alibratedBy

C

107

CalibratedAt

108

DateCalibrated

109

DateCalibrationDue

110

PID_Kp

111

PID_Ki

112

PID_Kd

113

SensorTbl[0][Sensor Value]

114

SensorTbl[0][Flow]

115

SensorTbl[1][Sensor Value]

116

SensorTbl[1][Flow]

117

SensorTbl[2][Sensor Value]

118

SensorTbl[2][Flow]

119

SensorTbl[3][Sensor Value]

120

SensorTbl[3][Flow]

121

SensorTbl[4][Sensor Value]

122

SensorTbl[4][Flow]

123

SensorTbl[5][Sensor Value]

124

SensorTbl[5][Flow]

125

SensorTbl[6][Sensor Value]

126

SensorTbl[6][Flow]

127

SensorTbl[7][Sensor Value]

128

SensorTbl[7][Flow]

129

SensorTbl[8][Sensor Value]

130

SensorTbl[8][Flow]

131

SensorTbl[9][Sensor Value]

132

SensorTbl[9][Flow]

133

SensorTbl[10][Sensor Value]

134

SensorTbl[10][Flow]

Note: Values will be available for selected gas only.

Data Type

float
float

loat

f

loat

f

loat

f

loat

f
float
float
float

loat

f

har

c

har

c

loat

f
float
char
float

loat

f

loat

f

loat

f

Notes

Gain for DRC Lag Constant [Do Not Alter]
Gain for DRC Lag Constant [Do Not Alter]

ain for DRC Lag Constant [Do Not Alter]

G

ain for DRC Lag Constant [Do Not Alter]

G

-Factor Mode: D-Dis’d, I-Internal, U-User Def’d

K

emp. Alarm Mode [‘R’ - Enabled, ‘S’ - Disabled]

T

ow Temp. Alarm Setting [0 to 50°C]

L
High Temp. Alarm Setting [0 to 50°C]
Press Alarm Mode [‘R’ - Enabled, ‘S’ - Disabled]
Low Press. Alarm Setting [0 to 100 PSI]

igh Press. Alarm Setting [0 to 100 PSI]

H

esistance when last AutoZero was done [Counts]

R

esistance correction coeffecient [PFS/count]

R

alibration Table

C

as Dependent Variables

G

ata Type

D

har[27]

c
float
float
float
float

har[27]

c

har[20]

c
char[20]
char[10]
char[10]
float
float
float
uint
float
uint
float
uint
float
uint
float
uint
float
uint
float
uint
float
uint
float
uint
float
uint
float
uint
float

otes

N

ame of Gas [If not calibrated = ‘Uncalibrated’]

N
Full Scale Range in SLPM
Standard Temperature
Standard Pressure
Gas Standard Density

ame of Gas used for Calibration

N

If not calibrated = ‘Uncalibrated’]

[

ame of person who performed actual calibration

N
Name of Calibration Facility
Calibration Date
Date Calibration Due
Reserved
Reserved
Reserved
Index 0: Must be 120 (zero value) Do not Alter!
Index 0: Must be 0.0 (zero PFS) Do not Alter!

10.0% FS A/D Value from Sensor [counts]
Actual Flow in PFS [0.1]

20.0% FS A/D Value from Sensor [counts]
Actual Flow in PFS [0.2]

30.0% FS A/D Value from Sensor [counts]
Actual Flow in PFS [0.3]

40.0% FS A/D Value from Sensor [counts]
Actual Flow in PFS [0.4]

50.0% FS A/D Value from Sensor [counts]
Actual Flow in PFS [0.5]

60.0% FS A/D Value from Sensor [counts]
Actual Flow in PFS [0.6]

70.0% FS A/D Value from Sensor [counts]
Actual Flow in PFS [0.7]

80.0% FS A/D Value from Sensor [counts]
Actual Flow in PFS [0.8]

90.0% FS A/D Value from Sensor [counts]
Actual Flow in PFS [0.9]

100.0% FS A/D Value from Sensor [counts]
Flow in PFS. Should be 1.0. Do not Alter!

Page 17

NOTICE

NOTICE

APPENDIX II - Internal “K” Factors

-factors at best are only an approximation. K factors should not be used in applications that require accuracy better than ±5 to 10%.

K

ensity

ndex

I

Actual Gas

0

ir

A

1

rgon Air

A

2

cetylene C

A

3

mmonia NH

A

4

Butane C4H

5

Chlorine Cl

6

Carbon Monoxide C

7

arbon Dioxide CO

C

8

hloroform CHCl

C

9

thane C

E
10
11
12

3

1

4

1
15
16
17
18

9

1

0

2

1

2
22

3

2

4

2

5

2
26
27
28
29
30
31

2H6

thylene C

E

Freon-134A CF3CH2F

Fluorine F

Fluoroform (Freon-23) CHF

elium He

H

ydrogen H

H

Hydrogen Chloride HCl

Hydrogen Sulfide H

Hexane C

Methane CH

eon NE

N

itrous Oxide N

N

Nitrogen Dioxide NO

Nitric Oxide NO

itrogen Trifluoride NF

N

xygen O

O

zone

O

Propane C

Propylene C3H

Sulfur Dioxide SO

Sulfur Hexafluoride SF

Xenon Xe

2

2H4

2

6H14

2

3H8

2H2

10

2

2

Cp
(Cal/g)

.
.
.
.
.4007
.114
.2488
.
.
.
.
.127
.1873
.176
1
3
.1912
.2397
.3968
.5328
.
.
.1933
.2328
.
.
.
.399
.366
.1488
.1592
.0378

K-Factor
Relative to N

.0000

1

.4573

1

5829

.

7310

3

.
.2631
.86

0

2

3

1.00
7382

.

3912

.

50

.

60

.
.5096
.9784
.4967

3

.454

1

.0106

1

1.000

S

2

4

O

2

2

.80
.1792
.7175

.46

1

7128

.
.737
.990

4802

.

3

9926

.

446

.
.35

6

2

.40
.69
.2635

6

1.44

240
1244
4036
492

2016
1309
420
365

.241
.419

246
2088

1797
2193
195

D

g/l)

(

1.293

1.782

1.162
760

.

.593

2

.163

3

.250

1

1.964

5.326

1.342

.251

1

.224

4

.69 5

1

3.127

.1786
.0899

1.627

.520

1

.845

3

715

.
.900

1.964

2.052

1.339

.168

3

.427

1

.114

2

1.967

1.877

2.858

6.516

5.858

APPENDIX III - Gas Factor Table (“K Factors”)

K-factors at best are only an approximation. K factors should not be used in applications that require accuracy better than ±5 to 10%.

Density

Index

Actual Gas

0

Acetylene C

1

Air

2

Allene (Propadiene) C

3

Ammonia NH

4

Argon Ar (<= 10 L/min)

2H2

3H4

3

Argon AR-1 (>= 10 L/min)

5

Arsine AsH

6

Boron Trichloride BCl

7

Boron Trifluoride BF

8

Bromine Br

9

Boron Trobromide Br

10

Bromine PentaTrifluoride BrF

11

Bromine Trifluoride BrF

12

Bromotrifluoromethane (Freon-13 B1) CBrF

13

1,3 - Butadiene C4H

14

Butane C4H

15

1 - Butene C4H

16

2 - Butene C4H8 CIS

17

2 - Butene C

18

Carbon Dioxide CO
Carbon Dioxide CO

19

Carbon Disulfide CS

20

Carbon Monoxide CO

21

Carbon Tetrachloride CCl

22

Carbon Tetrafluoride (Freon-14) CF

23

Carbonyl Fluoride COF

24

Carbonyl Sulfide COS

25

Chlorine Cl

26

Chlorine Trifluoride CIF

27

Chlorodifluoromethane (Freon-22) CHCIF

28

Chloroform CHCl

29

Chloropentafluoroethane (Freon-115) C2CIF

30

Chlorotrifluromethane (Freon-13) CCIF

31

Cyanogen C2N

32

Cyanogen Cloride CICN

33

Cyclopropane C

34

Deuterium D

35

Diborane B2H

3

2

10

4H8

2

2

8

TRANS

3

2

3H5

6

3

3

3

3

6

(<10 L/min)

2

-1 (<10 L/min)

2

2

4

2

3

K-Factor
Relative to N

.5829

1.0000
.4346
.7310

1.4573

1.205
.6735
.4089
.5082
.8083
.38

3

.26
.3855
.3697
.3224

5

.2631
.2994
.324
.291
.7382
.658
.6026

1.00
.31

4

.42
.5428
.6606
.86
.4016
.4589

2

.3912
.2418

5

.3834

3

.61
.6130
.4584

1.00
.4357

2

Cp
(Cal/g)

.4036
.240
.352
.492
.1244
.1244
.1167
.1279
.1778
.0539
.0647
.1369
.1161
.1113
.3514
.4007
.3648
.336
.374
.2016
.2016
.1428
.2488
.1655
.1654
.1710
.1651
.114
.1650
.1544
.1309
.164
.153
.2613
.1739
.3177

1.722
.508

(g/l)

1.162

1.293

1.787
.760

1.782

1.782

3.478

5.227

3.025

7.130

11.18

7.803

6.108

6.644

2.413

2.593

2.503

2.503

2.503

1.964

1.964

3.397

1.250

6.860

3.926

2.945

2.680

3.163

4.125

3.858

5.326

6.892

4.660

2.322

2.742

1.877

1.799

1.235

Page 18

Index

ctual Gas

A

36

Dibromodifluoromethane CBr2F

37

Dichlorodifluoromethane (Freon-12) CCl2F

8

3

Dichlofluoromethane (Freon-21) CHCl2F

9

3

ichloromethylsilane (CH

D

0

4

ichlorosilane SiH

D

1

4

ichlorotetrafluoroethane (Freon-114) C

D

42

,1-Difluoroethylene (Freon-1132A) C

1

43

Dimethylamine (CH3)2NH

44

Dimethyl Ether (CH3)2O

5

4

2,2-Dimethylpropane C3H

6

4

thane C

E

7

4

8

4
49
50
51

2

5

3

5
54
55
56
57

8

5

9

5

0

6
61

2

6

3

6

4

6
65
66
67

2H6

thanol C

E
E
E

2H6

thyl Acetylene C

thyl Chloride C
Ethylene C2H
Ethylene Oxide C2H4O
Fluorine F
F
F

2

luoroform (Freon-23) CHF

reon-11 CCl
Freon-12 CCl2F
Freon-13 CClF
Freon-13B1 CBrF
Freon-14 CF

reon-21 CHCl

F

reon-22 CHClF

F
Freon-113 CCl2FCClF
Freon-114 C2Cl2F

reon-115 C

F

reon-C318 C

F

ermane GeH

G
Germanium Tetrachloride GeCl
Helium He (<50 L/min)

l

C

2

2

O

4H6

l

C

2H5

4

F

3

2

3

3

4

F

2

2

2

4

lF

C

2

5

4F8

4

Helium He-1 (>50 L/min)
Helium He-2 (>10-50 L/min)

68

Hexafluoroethane C2F6(Freon-116)

69

Hexane C6H

70

Hydrogen H2-1 (<10-100 L)

14

Hydrogen H2-2 (>10-100 L)
Hydrogen H2-3 (>100 L)

71

Hydrogen Bromide HBr

72

Hydrogen Chloride HCl

73

Hydrogen Cyanide HCN

74

Hydrogen Fluoride HF

75

Hydrogen Iodide HI

76

Hydrogen Selenide H2Se

77

Hydrogen Sulfide H2S

78

Iodine Pentafluoride IF

79

Isobutane CH(CH3)

80

Isobutylene C4H

81

Krypton Kr

82

Methane CH4(<=10 L/min)

5

3

6

Methane CH4-1 (>=10 L/min)

83

Methanol CH

84

Methyl Acetylene C3H

85

Methyl Bromide CH2Br

86

Methyl Chloride CH3Cl

87

Methyl Fluoride CH3F

88

Methyl Mercaptan CH3SH

89

Methyl Trichlorosilane (CH3)SiCl

90

Molybdenum Hexafluoride MoF

91

Monoethylamine C2H5NH

92

Monomethylamine CH3NH

93

Neon NE

94

Nitric Oxide NO

95

Nitrogen N

96

Nitrogen Dioxide NO

97

Nitrogen Trifluoride NF

98

Nitrosyl Chloride NOCl

99

Nitrous Oxide N2O

100

Octafluorocyclobutane (Freon-C318) C4F

101

Oxygen O

102

Oxygen Difluoride OF

103

Ozone

104

Pentaborane B5H

105

Pentane C5H

106

Perchloryl Fluoride ClO3F

107

Perfluoropropane C3F

3

4

2

2

3

2

2

9

12

8

3)2

p

2

C

Cal/g)

(

.15
.1432
.140

1882

.

150

.

1604

.

224

.
.366
.3414
.3914

420

.

3395

.

3513

.

244

.
.365
.268
.1873

176

.

1357

.
.1432
.153
.1113
.1654

140

.

1544

.
.161
.160

164

.

185

.

1404

.
.1071

1.241

1.241

1.241
.1834
.3968

3.419

3.419

3.419
.0861
.1912
.3171
.3479
.0545
.1025
.2397
.1108
.3872
.3701
.0593
.5328
.5328
.3274
.3547
.1106
.1926
.3221
.2459
.164
.1373
.387
.4343
.246
.2328
.2485
.1933
.1797
.1632
.2088
.185
.2193
.1917
.195
.38
.398
.1514
.197

ensity

D
(g/l)

9.362

5.395
.592

4

.758

5

.506

4

.626

7

2.857

2.011

2.055
.219

3

.342

1

.055

2

.413

2

2.879

1.251

1.965
.695

1

.127

3

.129

6

5.395

4.660

6.644

3.926
.592

4

.858

3

.360

8

7.626

6.892

8.397

3.418
.565

9

1786

.
.1786
.1786

6.157

3.845

.0899
.0899
.0899

3.610

1.627

1.206

.893

5.707

3.613

1.520

9.90

3.593

2.503

3.739

.715
.715

1.429

1.787

4.236

2.253

1.518

2.146

6.669

9.366

2.011

1.386

.900

1.339

1.25

2.052

3.168

2.920

1.964

8.397

1.427

2.406

2.144

2.816

3.219

4.571

8.388

-Factor

K

elative to N

R

2

iCl

S

2

2H2F2

.1947
.3538

2

.4252

2522

.

4044

.

2235

l

.

C

2

2F4

4271

.
.3714
.3896

12

.2170

50

.

3918

.

3225

.

3891

.
.60
.5191
.9784

4967

3

.

3287

.
.3538
.3834
.3697
.4210

4252

.

4589

.
.2031
.2240

2418

.

1760

.

5696

.

4

.2668

1.454

2.43

2.05
.2421
.1792

1.0106

1.35

1.9

1.000

1.000
.764
.9998
.9987
.7893
.80
.2492
.27
.2951

1.453
.7175
.75
.5843
.4313
.5835
.6299
.68
.5180

3

6

2

2

.2499
.2126
.3512
.51

1.46
.990

1.000
.737
.4802
.6134
.7128
.176

8

.9926
.6337
.446
.2554
.2134
.3950
.174

Page 19

Index

ctual Gas

A

108

Phosgene COCl

109

Phosphine PH

10

1

Phosphorous Oxychloride POCl

11

1

hosphorous Pentafluoride PH

P

12

1

hosphorous Trichloride PCl

P

13

1

ropane C

P

114

ropylene C

P

115

Silane SiH

116

Silicon Tetrachloride SiCl

17

1

Silicon Tetrafluoride SiF

18

1

ulfur Dioxide SO

S

19

1

ulfur Hexafluoride SF

S

20

1

ulfuryl Fluoride SO

S

121

etrafluoroethane (Forane 134A) CF

T

122

Tetrafluorohydrazine N2F

123

Trichlorofluoromethane (Freon-11) CCl3F

24

1

Trichlorosilane SiHCl

25

1

,1,2-Trichloro-1,2,2 Trifluoroethane

1

Freon-113) CCl

(

126

Triisobutyl Aluminum (C4H9)AL

127

Titanium Tetrachloride TiCl

128

Trichloro Ethylene C2HCl

29

1

Trimethylamine (CH3)3N

30

1

ungsten Hexafluoride WF

T

31

1

ranium Hexafluoride UF

U

132

Vinyl Bromide CH2CHBr

33

1

Vinyl Chloride CH2CHCl

34

1

enon Xe

X

3H8

4

3H6

2

3

2

6

2F2

3

CClF

F

2

APPENDIX IV - Component Diagram

GFM3/4 Analog PC Board TOP

p

2

C

Cal/g)

(

.1394
.2374
.1324

1610

.

1250

.

399

.

366

.
.3189
.1270
.1691

1488

.

1592

.

1543

.

127

.
.182
.1357
.1380

161

.

.508
.120
.163
.3710

0810

.

0888

.
.1241
.12054

0378

.

ensity

D
(g/l)

4.418

1.517
.843

6

.620

5

.127

6

.967

1

1.877

1.433

7.580
.643

4

.858

2

.516

6

.562

4

4.224

4.64

6.129
.043

6

.36

8

8.848

8.465

5.95

2.639

3.28

1

5.70

1

.772

4

2.788

5.858

-Factor

K

elative to N

R

.4438
.759

3

5

3

.36

3021

.

30

.

35

.

40

.
.5982

4

4

4

.284
.3482

69

.

2635

.

3883

.

5096

H

.

C

F

3

2

.3237
.3287
.3278

2031

.

2

4

3

6

6

.0608
.2691
.32
.2792

2541

.

1961

.
.4616
.48

.44

1

Page 20

APPENDIX IV - Component Diagram

GFM3/4 Analog PC Board BOTTOM

APPENDIX IV - Component Diagram

GFM3/4 Digital PC Board TOP

Page 21

PPENDIX IV - Component Diagram

6-3/4

[171.70]

5-1/4

[133.10]

1-1/2

[38.10]

1-11/32

[34.29]

1-21/32
[42.16]

3/4

[19.30]

5-1/4

[133.60]

2

[51.05]

FLOW
PRESSURE
TEMPERATURE

FLOW

GFM3

2X PROCESS

CONNECTIONS

WITH

COMPRESSION

FITTINGS ATTACHED

1-21/32

[42.16]

4-1/4

[107.87]

3/4

[19.30]

5-1/4

[133.60]

2

[51.05]

6-3/4

[171.70]

5-1/4

[133.10]

1-1/2

[38.10]

1-11/32

[34.29]

FLOW
PRESSURE
TEMPERATURE

PROCESS

CONNECTIONS

WITH

COMPRESSION

FITTINGS ATTACHED

GFM3

FLOW

A

FM3/4 Digital PC Board BOTTOM

G

PPENDIX V

A

Dimensional Drawings

GFM3

GFM4

MAINTENANCE/REPAIR

Upon final installation of the Series GFM3/4, no routine maintenance is required. The Series GFM3/4 is not field serviceable and should be returned if repair is needed. Field
repair should not be attempted and may void warranty.

Page 22

Phone: [phone] www.dwyer-inst.com

WARRANTY/RETURN

Refer to “Terms and Conditions of Sales” in our catalog and on our website. Contact customer service to receive a Return Goods Authorization number before shipping the
product back for repair. Be sure to include a brief description of the problem plus any additional application notes.

©Copyright 2013 Dwyer Instruments, Inc. Printed in U.S.A. 5/13 FR# RA-444051-00

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A. Fax: [phone] e-mail: [e-mail]