Dwyer GFM2 User Manual

Series GFM2 Digital Mass Flow Meter

Installation and Operating Instructions

Bulletin F-GFM2

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 GFM2 Flow Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

1

.1 Inspect Package for External Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

1

1.2 Unpack the Mass Flow Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

1.3 Returning Merchandise for Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

. Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

2

.1 Primary Gas Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

2

.2 Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

2

.2.1 Power Supply Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

2

2.2.2 Output Signal Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

2.2.3 Output Communication Parameters and Connections . . . . . . . . . . .3

. Principle of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

3

. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

4

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

5.1 Preparation and Warm Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

5.2 Swamping Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

.3 GFM2 Parameters Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

5

.3.1 Engineering Units Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

5

.3.2 Gas Table Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

5

5.3.3 Totalizer Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

5.3.4 Flow Alarm Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

5.3.5 Relay Assignment Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

5.3.6 K-Factors Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

.3.7 Zero Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

5

.3.8 Self Diagnostic Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

5

.4 Analog Output Signals Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

5

. Calibration Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

7

.1 Flow Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

7

.2 Gas Flow Calibration of GFM2 Mass Flow Meters . . . . . . . . . . . . . . . . . .8

7

.2.1 Connections and Initial Warm Up . . . . . . . . . . . . . . . . . . . . . . . . . . .8

7

7.2.2 ZERO Check/Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

7.2.3 Gas Linearization Table Adjustment . . . . . . . . . . . . . . . . . . . . . . . . .8

7.3 Analog Output Calibration of GFM2 Mass Flow Meters . . . . . . . . . . . . . . .9

.3.1 Initial Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

7

.3.2 Gas Flow 0 to 5 VDC Analog Output Calibration . . . . . . . . . . . . . . . .9

7

.3.3 Gas Flow 4 to 20 mA Analog Output Calibration . . . . . . . . . . . . . . . .9

7

8. RS-485/RS-232 Software Interface Commands . . . . . . . . . . . . . . . . . . . . . . .9

8.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

8.2 Commands Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

.3 ASCII Commands Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

8

. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

9

9.1 Common Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

9.2 Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

9.3 Technical Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

0. Calibration Conversions from Reference Gases . . . . . . . . . . . . . . . . . . .13

1

ppendix I GFM2 EEPROM Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

A

Appendix II Internal User Selectable Gas Factor Table

ppendix III Gas Factor Table (“K” Factors) . . . . . . . . . . . . . . . . . . . . . .16

A

ppendix IV Component Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

A

(Internal “K” Factors) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

6. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

6.2 Flow Path Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

6.2.1 Restrictor Flow Element (RFE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

6.2.2 GFM2 Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Appendix V Dimensional Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Appendix VI Maintenance/Repair, Warranty/Return . . . . . . . . . . . . . . . . .19

Page 2

. UNPACKING THE GFM2 MASS FLOW METER

1

1.1 - Inspect Package for External Damage

Your GFM2 Mass Flow Meter was carefully packed in a sturdy cardboard carton,

ith anti-static cushioning materials to withstand shipping shock. Upon receipt,

w

nspect the package for possible external damage. In case of external damage to

i

he package contact the shipping company immediately.

t

1.2 - Unpack the Mass Flow Meter

Open the carton carefully from the top and inspect for any sign of concealed
shipping damage. In addition to contacting the shipping carrier please forward a

opy of any damage report to your distributor or Dwyer Instruments, Inc directly.

c

hen unpacking the instrument please make sure that you have all the items

W

ndicated on the Packing List. Please report any shortages promptly.

i

1.3 - Maintenance/Repair

Upon final installation of the Series GFM2, no routine maintenance is required. The
Series GFM2 is not field serviceable and should be returned if repair is needed.

ield repair should not be attempted and may void warranty.

F

arranty/Return

W

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.

. INSTALLATION

2

.1 - Primary Gas Connections

2

Please note that the GFM2 Mass Flow Meter will not operate with liquids. Only
clean gases are allowed to be introduced into the instrument. If gases are
contaminated they must be filtered to prevent the introduction of impediments into
the sensor.

CAUTION

application. For more information, contact your distributor or Dwyer.

Attitude limit of Mass Flow Meter is ±15° 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 GFM2 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

pressure above 500 PSIA (34.47 bars) will seriously damage the flow sensor and
may cause serious injury or death.

GFM2 transducers are supplied with standard 1/4˝ or 3/8˝ inlet and outlet
compression fittings which should not be removed unless the meter is being
cleaned or calibrated for a new flow range.

FM2 transducers should not be used for monitoring OXYGEN

G

as unless specifically cleaned and prepared for such

g

For models GFM2 models the maximum pressure in the gas
line should not exceed 500 PSIA (34.47 bars). Applying

CAUTION

2.2.2 - Output Signals Connections

AUTION

C

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

GFM2 Mass Flow Meters are equipped with either calibrated 0 to 5 VDC (0 to 10

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.

l

AUTION

C

output signals!

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

P
M

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

he digital interface operates via RS-485 (optional RS-232 or Profibus DP is

T

vailable) and provides access to applicable internal data including: flow, CPU

a

emperature, pressure reading, auto zero, totalizer and alarm settings, gas table,

t
conversion factors and engineering units sel ection, dynamic response
compensation and linearization table adjustment.

Communication Settings:

RS-485 Communication Interface Connection:

The RS-485 converter/adapter has to be configured for: multidrop, 2 wire, half
duplex mode. 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 8 of the 15 pin "D" connector (TX-)
RS-485 T(+) or R(+) -------- pin 15 of the 15 pin "D" connector (RX+)
RS-485 GND (if available) -------- pin 9 of the 15 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 8 of the 15 pin "D" connector (TX)
RS-232 TX
(pin 3 on the DB9 connector) -------- pin 15 of the 15 pin "D" connector (RX)
RS-232 GND
(pin 5 on the DB9 connector) -------- pin 9 of the 15 pin "D" connector (GND)

Do not apply power voltage above 26 VDC. Doing so will cause

FM2 damage or faulty operation.

G

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

All 4 to 20 mA current loop outputs are self-powered (non­isolated). Do not connect an external voltage source to the

lus (+) ------------------- pin 2 of the 15 pin "D" connector

inus (-) ------------------- pin 1 of the 15 pin "D" connector

aud rate: -------- 9600 baud

B

top bit: -------- 1

S
Data bits: -------- 8
Parity: -------- None
Flow Control: -------- None

Using a Helium Leak Detector or other equivalent method perform a thorough
leak test of the entire system. (All GFM2’s are checked prior to shipment for
leakage within stated limits. See specifications in this manual.)

2.2 - Electrical Connections

GFM2 is supplied with a 25 pin "D" connector. Pin diagram is presented in figure
b-1.

2.2.1 - Power Supply Connections

The power supply requirements for GFM2 transduers are: 11 to 26 VDC, (unipolar
power supply)

DC Power (+) --------------- pin 7 of the 15 pin "D" connector
DC Power (-) --------------- pin 5 of the 15 pin "D" connector

Page 3

IN GFM2 FUNCTION

P

1 Common, Signal Ground

For Pin 2 (4 to 20 mA return)

2 0 to 5 VDC or 4 to 20 mA

low Signal Output

F

Relay No. 2 - Normally Open

3

ontact

C

4 Relay No. 2 - Common

Contact

5 Common, Power Supply

- DC power for 11 to 26 VDC)

(

Relay No. 1 - Common

6

ontact

C

Plus Power Supply

7

(+ DC power for 11 to 26 Vdc)
8 RS485 (-) (Optional RS232 TX)
9 RS232 Signal GND (RS-485

ND Optional)

G

0 Do not connect

1

Test/Maintenance terminal)

(

11 Relay No. 2 - Normally Closed

Contact
12 Relay No. 1 - Normally Open

Contact

3 Relay No. 1 - Normally Closed

1

ontact

C

4 Do not connect

1

(Test/Maintenance terminal)

5 RS485 (+) (Optional RS232

1

X) Shield Chassis Ground

R

OTICE

N

onconforming patterns and the numbering sequence on your mating

n
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

In general, "D" Connector numbering patterns are

tandardized. There are, however, some connectors with

s

Make sure power is OFF when connecting or disconnecting
any cables in the system.

dditionally, the GFM2 Mass Flow Meter incorporates a precision analog

A

icrocontroller and non-volatile memory that stores all hardware specific variables

m

nd up to 10 different calibration tables. The flow rate can be displayed in 23

a

ifferent volumetric or mass flow engineering units. Flow meter parameters and

d
functions can be programmed remotely via the RS-232/RS-485 interface or
optional Profibus DP interface. GFM2 flow meters support various functions
including: programmable flow totalizer, low, high or range flow alarm, automatic

ero adjustment (activated via local button or communication interface), 2

z

rogrammable SPDT relays output, 0 to 5 VDC / 4 to 20 mA analog outputs (jumper

p

electable), self diagnostic alarm, 36 internal and user defined K-factor. Optional

s

ocal 2x16 LCD readout with adjustable back light provides flow rate and total

l
volume reading in currently selected engineering units and diagnostic events
indication.

PECIFICATIONS

S

ervice: Clean gases compatible with wetted parts.

S

etted Materials:

W

GFM2-X-X-A: Anodized aluminum, brass, 316 SS fluoroelastomer O-rings;
GFM2-X-X-S: 316 SS, and fluoroelastomer O-rings; Buna-N, EPR and PTFE

Accuracy: ±1% FS.

epeatability: ±0.25% FS.

R

esponse Time: 2 seconds to within ±2% of actual flow.

R

utput Signal: Linear 0 to 5 VDC (3000 Ω min. load impedance) and 4 to 20 mA

O

(500 Ω max. loop resistance).

Max. Particulate Size: 5 microns.
Temperature Limits: 32 to 122°F (0 to 50°C).
Power Supply: 11 to 26 VDC.

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

isplay: 2 x 16 character LCD.

D
Pressure Limits: 500 psig (34.5 bar).
Leak Integrity: 1 x 10-9 smL/sec of helium.
Weight: 1.05 lb (0.48 kg).

O-rings optional.

The (+) and (-) power inputs are each protected by a 300 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 feet (3
meters).

Use of the GFM2 flow transducer in a manner other than that specified in this
manual or in writing from Dwyer, 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 temperature
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.

Page 4

low Rates

F

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

F

or other gases use the K factor as a multiplier from APPENDIX III.

F

low Rate

odel

M

FM2-X-101

G

odel

M

std liters/min)

(

up to 10

GFM2-X-101 Transmitter

F

Maximum Pressure Drop

)

mm H

0

(

2

130

eight

W

2.20 lb (1.00 kg)

psid)

(

hipping Weight

S

kPa)

(

.18

.275

0

1

3.70 lb (1.68 kg)

Table IV - Pressure Drops

5. OPERATING INSTRUCTIONS

NOTICE

uring the first 6 minutes of the initial powering of the GFM2

D
transducer, the status LED will emit a constant amber light.

or the GFM2 transducer with LCD option: If the LCD diagnostic is activated, the

F
second line of the LCD will display the time remaining until the end of the warm
up period (Minutes:Seconds format) and will alternatively switch to Totalizer reading
indication every 2 seconds.

F: 50.0 L/min

** WarmUp 2:39 **

5.1 - Preparation and Warm Up

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

I

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 2 seconds you will see on the

W
LCD display: the product name, the software version, and revision of the
EEPROM table (applicable for LCD option only).

S: Ver1.4 Rev.A0

igure b-2: GFM2 First Banner Screen

F

ithin the next 2 seconds, the RS-485 network address, the analog output settings,

W
and currently selected gas calibration table will be displayed (applicable for LCD
option only).

Ad: 11 Out: 0 to 5 VDC

Gas# 1 AIR

Figure b-3: GFM2 Second Banner Screen

NOTICE

Actual content of the LCD screen may vary depending on the
model and device configuration.

After 2 seconds, the LSD display switches to the main screen with the following
information:

- Mass Flow reading in current engineering units (upper line).

- Totalizer Volume reading in current volume or mass based engineering units
(lower line).

F: 50.0 L/min

T: 75660.5 Ltr

Figure b-4: GFM2 Main Screen

NOTICE

During initial powering of the GFM2 transducer, the flow output signal will be
indicating a higher than usual output. This is an indication that the GFM2
transducer has not yet attained its minimum operating temperature. This condition
will automatically cancel within a few minutes and the transducer should eventually
indicate 0.

Allow the Digital Mass Flow Meter to warm-up for a MINIMUM
of 6 minutes.

igure b-5: GFM2 Main Screen During Sensor Warm Up Period.

F

OTICE

N

After 6 minutes of the initial powering of the GFM2 transducer,
the status LED will emit a constant GREEN light (normal

operation, ready to measure). For GFM2 with LCD option, the screen will reflect

low and totalizer reading. (see Figure b-4).

f

.2 Swamping Condition

5

f a flow of more than 10% above the maximum flow rate of the Mass Flow Meter

I
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

bove 110% of maximum calibrated flow may increase recovery time.

a

.3 GFM2 Parameters Settings

5

5.3.1 Engineering Units Settings

The GFM2 Mass Flow Meter is capable of displaying flow rate with 23 different
Engineering Units. Digital interface commands (8.3 ASCII Command Set “GFM2
SOFTWARE INTERFACE COMMANDS”) are provided to:

- get currently active Engineering Units

- set desired Engineering Units.

The following Engineering Units are available:

Units of Measure

Number

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

Index

0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22

Flow Rate

Engineering

Units

%
mL/sec
mL/min
mL/hr
L/sec
L/min
L/hr

3

m

/sec

3

m

/min

3

m

/hr

3

ft

/sec

3

ft

/min

3

ft

/hr
g/sec
g/min
g/hr
kg/sec
kg/min
kg/hr
Lb/sec
Lb/min
Lb/hr
User

Totalizer

Engineering

Units

%s
mL
mL
mL
Ltr
Ltr
Ltr

3

m

3

m

3

m

3

ft

3

ft

3

ft
g
g
g
kg
kg
kg
Lb
Lb
Lb
UD

Description

Percent of full scale
Mililiter per second
Mililiter per minute
Mililiter per hour
Liter per second
Liter per minute
Liter per hour
Cubic meter per second
Cubic meter per minute
Cubic meter per hour
Cubic feet per second
Cubic feet per minute
Cubic feet per hour
Grams per second
Grams per minute
Grams per hour
Kilograms per second
Kilograms per minute
Kilograms per hour
Pounds per second
Pounds per minute
Pounds per hour
User Defined

Page 5

NOTICE

automatically.

Once Flow Unit of Measure is changed, the Totalizer’s
Volume/Mass based Unit of Measure will be changed

5.3.2 Gas Table Settings

The GFM2 Mass Flow Meter is capable of storing calibration data for up to 10

ifferent gases. Digital interface commands are provided to:

d

get currently active Gas Table number and Gas name

­ set desired Gas Table.

-

OTICE

N

rdered). If instead of the valid Gas name (for example NITROGEN), the LCD

o

creen or digital interface displays Gas designator as “Uncalibrated”, then the

s
user has chosen the Gas Table which was not calibrated. Using an “Uncalibrated”
Gas Table will result in erroneous reading.

5.3.3 Totalizer Settings

The total volume of the gas is calculated by integrating the actual gas flow rate
with respect to the time. Digital interface commands are provided to:

reset 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 via digital interface

The Totalizer has several attributes which may be configured by the user. These

ttributes control the conditions which cause the Totalizer to start integrating the gas

a

low and also to specify actions to be taken when the Total Volume is outside the

f

pecified limit.

s

OTICE

N

ntered in % FS engineering unit. The Totalizer will not totalize until the flow rate

e

ecomes equal to or more than the Totalizer Start value. Totalizer Stop values

b

ust be entered in currently active volume / mass based engineering units. If the

m
Totalizer Stop at preset total volume feature is not required, then set Totalizer
Stop value to 0.

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

y default the GFM2 is shipped with at least one valid

B

alibration table (unless optional additional calibrations were

c

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

Latch Mode - Controls Latch feature when Relays are assigned to Alarm event.
Following settings are available:

- Latch feature is disabled for both relays

0

- Latch feature is enabled for Relay#1 and disabled for Relay#2

1

- Latch feature is enabled for Relay#2 and disabled for Relay#1

2

- Latch feature is enabled for both relays.

3

NOTICE

NOTICE

onditions. If Relay is assigned to the Alarm event, in some cases, the Alarm

c

atch feature may be desirable.

L

The current Flow Alarm settings and status are available via digital interface (8.3
ASCII Command Set “GFM2 SOFTWARE INTERFACE COMMANDS”).

.3.5 Relay Assignment Settings

5

wo sets of dry contact relay outputs are provided to actuate user supplied

T
equipment. These are programmable via digital interface such that the relays can
be made to switch when a specified event occurs (e.g. when a low or high flow
alarm limit is exceeded or when the totalizer reaches a specified value).

he user can configure each Relay action from 6 different options:

T

o Action : (N) No assignment (relay is not assigned to any events and not

N

nergized).

e
Totalizer > Limit : (T) Totalizer reached preset limit volume.

igh Flow Alarm : (H) High Flow Alarm condition.

H

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

L
Range between H&L : (R) Range between High and Low Flow Alarm condition.
Manual Enabled : (M) Activated regardless of the Alarm and Totalizer conditions.

5.3.6 K-Factors Settings

onversion factors relative to nitrogen for up to 36 gases are stored in the GFM2

C
(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
digital interface commands.

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

I

larm event, the corresponding Relay will be energized.

A

y default, flow alarm is non-latching. That means the alarm is

B

ndicated only while the monitored value exceeds the specified

i

Local maintenance push button is available for manual Totalizer reset on the field.
The maintenance push button is located on the right side of the flow meter inside
the maintenance window above the 15 pin D-connector (see Figure C-1 “GFM2
configuration jumpers”).

NOTICE

sequence is recommended:

1. Disconnect GFM2 from the power.

2. Press maintenance push button (do not release).

3. Apply power to the GFM2 while holding down the maintenance push button.

4. Release maintenance push button after 6 seconds. For GFM2 with optional

LCD, when GFM2 Main Screen appears (see Figure b-4).

5.3.4 Flow Alarm Settings

GFM2 provides the user with a flexible alarm/warning system that monitors the Gas
Flow for conditions that fall outside configurable limits as well as visual feedback for
the user via the status LED and LCD (only for devices with LCD option) or via a
Relay contact closure.

The flow alarm has several attributes which may be configured by the user via a
digital interface. These attributes control the conditions which cause the alarm to
occur and to specify actions to be taken when the flow rate is outside the specified
conditions.

Mode Enable /Disable - Allows the user to Enable/Disable Flow Alarm.
Low Alarm - The value of the monitored Flow in % FS below which is considered an
alarm condition.

NOTICE

High Alarm - The value of the monitored Flow in % FS above which is considered
an alarm condition.

NOTICE

Action Delay - The time in seconds that the Flow rate value must remain above the
high limit or below the low limit before an alarm condition is indicated. Valid settings
are in the range of 0 to 3600 seconds.

In order to locally Reset Totalizer, the reset push button must
be pressed during power up sequence. The following

The value of the Low alarm must be less than the value of the
High Alarm.

The value of the High alarm must be more than the value of
the Low Alarm.

The available K Factor settings are:

• Disabled (K = 1).

• Internal Index The index [0-35] from internal K factor table (see APPENDIX II).

• User Defined User defined conversion factor.

NOTICE

5.3.7 Zero Calibration

The GFM2 includes an auto zero function that, when activated, automatically
adjusts the mass flow sensor to read zero. The initial zero adjustment for your
GFM2 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.

Shut off the flow of gas into the Digital Mass Flow Meter. To ensure that no seepage
or leak occurs into the meter, it is good practice to temporarily disconnect the gas
source. The Auto Zero may be initiated via digital communication interface or locally
by pressing the maintenance push button, which is located on the right side of the
flow meter inside the maintenance window above the 15 pin D-connector (see
Figure C-1 “GFM2 configuration jumpers”).

NOTICE

will prevent initiating Auto Zero function via the maintenance push button before
the 6 minutes sensor warm up period has elapsed.

To start Auto Zero locally, press the maintenance push button. The status LED will
flash not periodically with the RED light. On the GFM2 with optional LCD, the
following screen will appear:

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

Before performing Zero Calibration, make sure the device is
powered up for at least 15 minutes and absolutely no flow

The same maintenance push button is used for Auto Zero
initiation and Totalizer reset. The internal diagnostic algorithm

AUTOZERO IS ON!

Figure b-6: GFM2 Screen in the Beginning of Auto Zero Procedure

Page 6

he Auto Zero procedure normally takes 1 to 2 minutes during which time the DP

T

ero counts and the Sensor reading changes approximately every 3 to 6 seconds.

Z

AUTOZERO IS ON!

S: 405 DP: 512

Figure b-7: GFM2 During the Auto Zero Procedure

The nominal value for a fully balanced sensor is 120 counts. If the GFM2’s digital

ignal processor was able to adjust the Sensor reading within 120 ± 10 counts,

s

hen Auto Zero is considered successful. The status LED will return to a constant

t

REEN light.

G

NOTICE

f the device was unable to adjust the Sensor reading to within 120 ± 10 counts,

I

hen Auto Zero is considered as unsuccessful. The constant RED light will appear

t

n the status LED. The user will be prompted with the “AutoZero ERROR!” screen.

o

OTICE

N

5.3.8 Self Diagnostic Alarm

FM2 series Mass Flow Meters are equipped with a self-diagnostic alarm which is

G

vailable via multicolor LED, digital interface and on screen indication (for devices

a

ith optional LCD). The following diagnostic events are supported:

w

Number

1

2

3

4

5
6
7

8
9
10

NOTICE

event with the highest priority level will be indicated on the status LED and
displayed on the LCD (if equipped). All diagnostic events may be accessed
simultaneously via digital communication interface.

5.4 Analog Output Signals Configuration

GFM2 series Mass Flow Meters are equipped with calibrated 0 to 5 VDC and 4 to
20 mA output signals. The set of the jumpers (J7A, J7B, J7C) located on the right
side of the flow meter, inside of the maintenance window above the 15 pin D­connector (see Figure C-1 “GFM2 configuration jumpers”) are used to switch
between 0 to 5 VDC or 4 to 20 mA output signals (see Table VI). Analog output
signals of 0 to 5 VDC and 4 to 20 mA are attained at the appropriate pins of the 15­pin "D" connector (see Figure b-1) on the side of the GFM2 transducer.

The actual value of the Sensor and DP counts will vary for
each GFM2.

For GFM2 with RS-232 option all Auto Zero status info
available via digital communication interface.

LED Color

Diagnostic Alarm Description

uto Zero procedure is running

A

FATAL ERROR (reset or maintenance
service is required for return in to the
normal operation)
CPU Temperature too high (Electronics
Overheating)
Sensor in the warm up stage (first 6
minutes after power up sequence,
normal operation, no critical diagnostic
events present)
Flow Sensor Temperature too low
Flow Sensor Temperature too high
Totalizer Reading hit preset limit

Low Flow Alarm conditions
High Flow Alarm conditions
Normal operation, no diagnostic events

[0] - Priority Level is highest (most important). When two or
more diagnostic events are present at the same time, the

and Pattern

ot periodically

N
flashing RED
Constant RED

Flashing RED/UMBER

Constant UMBER

Flashing UMBER/OFF
Flashing RED/OFF
Flashing
GREEN/UMBER
Flashing GREEN/OFF
Flashing GREEN/RED
Constant GREEN

Priority
Level

0

1

2

3

4
5
6

7
8
9

6
7

5

-10

-11

-9

4 to 20 mA

7.A

1

J

7.B

2

J

7.C

3

J

-5

-6

-7

Analog Signal Output

low Rate Output

F

Jumper Header J7

Table VI - Analog Output Jumper Configuration

ee APPENDIX IV for actual jumpers layout on the PCB.

S

NOTICE

6. MAINTENANCE

6.1 Introduction

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

I

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
crystallization. Other flow passages are also easily obstructed.

Therefore, great care must be exercised to avoid the introduction of any potential
flow impediment. To protect the instrument, a 50 micron (GFM2-X-010) filter is built

nto the inlet of the flow transducer. The filter screen and the flow paths may require

i

ccasional cleaning as described below. There is no other recommended

o

aintenance required. It is good practice, however, to keep the meter away from

m
vibration, hot or corrosive environments and excessive RF or magnetic interference.

If periodic calibrations are required, they should be performed by qualified
personnel and calibrating instruments, as described in section 7. It is recommended

hat units are returned to Dwyer for repair service and calibration.

t

WARNING

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.

CAUTION

6.2.1 Restrictor Flow Element (RFE)

The Restrictor Flow Element (RFE) is a precision flow divider inside the transducer
which 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 GFM2-X-010 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 to
the RFE. Be sure that no dust has collected on the O-ring seal.

NOTICE

CALIBRATION POINT BE CHECKED AFTER RE-INSTALLING THE INLET
FITTING.

igital output (communication) is simultaneously available with

D

nalog output.

a

O PROTECT SERVICING PERSONNEL IT IS MANDATORY

T

HAT ANY INSTRUMENT BEING SERVICED IS

T

DISASSEMBLY MAY COMPROMISE CURRENT
CALIBRATION.

OVER TIGHTENING WILL DEFORM AND RENDER THE RFE
DEFECTIVE. IT IS ADVISABLE THAT AT LEAST ONE

0 to 5 VDC

7.A

J

7.B

J

7.C

J

Page 7

. CALIBRATION PROCEDURES

7

OTICE

N

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

M

ARRANTY APPLICABLE.

W

7.1 Flow Calibration

wyer Instruments' Flow Calibration Laboratory offers professional calibration

D

upport for Mass Flow Meters using precision calibrators under strictly controlled

s

onditions. Calibrations can also be performed at customers' site using available

c

tandards.

s

Factory calibrations are performed using NIST traceable precision volumetric
calibrators incorporating liquid sealed frictionless actuators.

enerally, calibrations are performed using dry nitrogen gas. The calibration can

G

hen be corrected to the appropriate gas desired based on relative correction [K]

t
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 when a reference gas is found with
thermodynamic properties similar to the actual gas under consideration. The

ppropriate relative correction factor should be recalculated (see section 9).

a

t is standard practice to calibrate Mass Flow Meters with dry nitrogen gas at

I

70.0°F (21.1°C), 20 psia (137.9 kPa absolute) inlet pressure and 0 psig outlet

pressure. It is best to calibrate GFM2 transducers to actual operating conditions.
Specific gas calibrations of non-toxic and non-corrosive gases are available for
specific conditions. Please contact your distributor or Dwyer for a price quotation.

t is recommended that a flow calibrator be used which has at least four times better

I

ollective accuracy than that of the Mass Flow Meter to be calibrated.

c
Equipment required for calibration includes: a flow calibration standard, PC with
available RS-485/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). Using Dwyer supplied calibration and maintenance
software to simplify the calibration process is recommended.

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 GFM2 Mass Flow Meters

All adjustments in this section are made from the outside of the meter via digital
communication interface between a PC (terminal) and GFM2. There is no need to
disassemble any part of the instrument or perform internal PCB component
(potentiometers) adjustment.

GFM2 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 for more information.

7.2.1 Connections and Initial Warm Up

Power up the Mass Flow Meter for at least 15 minutes prior to commencing the
calibration procedure. Establish digital RS-485/RS-232 communication between
PC (communication terminal) and the GFM2. Start Dwyer supplied calibration and
maintenance software on the PC.

7.2.2 ZERO Check/Adjustment

Using Dwyer supplied calibration and maintenance software open Back Door
access:

REMOVAL OF THE FACTORY INSTALLED CALIBRATION

EALS AND/OR ANY ADJUSTMENTS MADE TO THE

S

.2.3 Gas Linearization Table Adjustment

7

OTICE

N

evice’s front label). There is no need to adjust the gas linearization table unless

d

inearity adjustment is needed, flow range has to be changed, or new additional

l

alibration is required. Any alteration of the gas linearization table will

c
VOID calibration warranty supplied with instrument.

as flow calibration parameters are separately stored in the Gas Dependent

G

ortion of the EEPROM memory for each of 10 calibration tables. See APPENDIX

p

for complete list of gas dependent variables.

I

OTICE

N

e applied to the currently selected gas. Use Gas Select command via digital

b

ommunication interface or Dwyer supplied calibration and maintenance software

c

o verify current gas table or select a new gas table.

t

Actual flow values are entered in normalized fraction format: 100.000 % FS
corresponds to 1.000000 flow value and 0.000 % FS corresponds to 0.000000 flow
value. The valid range for flow values is from 0.000000 to 1.000000 (note: GFM2

ill accept up to 6 digits after decimal point).

w

ensor readings are entered in counts of 12 bits ADC output and should always

S
be in the range of 0 to 4095. There are 11 elements in the table so the data should
be obtained at an increment of 10.0 % of full scale (0.0, 10.0, 20.0, 30.0, 40.0, 50.0,

60.0, 70.0, 80.0, 90.0 and 100.0 % FS).

f a new gas table is going to be created, it is recommended to start calibration

I

rom 100% FS. If only linearity adjustment is required, calibration can be

f

tarted in any intermediate portion of the gas table.

s

Using the flow regulator, adjust the flow rate to 100% of FS flow. Check the
flow rate indicated against the flow calibrator. Observe the flow reading on the
GFM2. If the difference between calibrator and GFM2 flow reading is more than

0.5% FS, consult factory.

If the GFM2 flow reading is more than the calibrator reading, the number of counts
in the Index 133 must be decreased. If the GFM2 flow reading is less than the
calibrator reading, the number of counts in the Index 133 must be increased. Once
Index 133 is adjusted with a new value, check the GFM2 flow rate against the
calibrator and, if required, perform additional adjustments for Index 133.

If a simple communication terminal is used for communication with the GFM2, 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 GFM2 is configured with RS-485 interface and has address “11”, the
following example will first read the existing value of Index 133 and then write a
new adjusted value:

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

NOTICE

includes an automated calibration procedure which may radically simplify reading
and writing for the EEPROM linearization table.

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

Your GFM2 Digital Mass Flow Meter was calibrated at the

actory for the specified gas and full scale flow range (see

f

Make sure the correct gas number and name selected are
current. All adjustments made to the gas linearization table will

It is recommended to use Dwyer supplied calibration and
maintenance software for gas table calibration. This software

Query/BackDoor/Open
When software prompts with Warning, click the [YES] button. This will open the
access to the rest of the Query menu.

Start Sensor Compensated Average reading:
Query/Read/ SensorCompAverage
This 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”).

Page 8

.3 Analog output Calibration of GFM2 Mass Flow Meters

7

FM2 series Mass Flow Meters are equipped with

G

alibrated 0 to 5 Vdc and 4 to 20 mA output signals. The set

c

f the jumpers (J7A, J7B, J7C) on the printed circuit board

o
is used to switch between 0 to 5 Vdc and 4 to 20 mA output
signals (Figure C-1 “GFM2 configuration jumpers).

CD

7C

J

7

J

-11

3-7

8-12

4-8

7B

7A

J

ON

J

5
1-5

-10

-9

6

2-6

unction

F

nalog

A
Output
RS485
Terminal Resistor

Figure C-1 GFM2 Analog Output Configuration

he GFM2 analog output calibration involves calculation

T

nd storing of the offset and span variables in the

a
EEPROM for each available output. The 0 to 5 VDC output
has only scale variable and 20 mA output has offset and
scale variables. The following is a list of the Gas
independent variables used for analog output computation:

to 5 VDC

0
4 to 20 mA

OFF

Jumpers

.3.3 Gas Flow 4 to 20 mA Analog Output Calibration

7

. Install jumpers J7A, J7B and J7C on the PC board for 4 to 20 mA output (see

1

able VI).

T

. Connect a certified high sensitivity multimeter set for the current measurement

2
to pins 2 (+) and 1 (-) of the 15 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:

AoutScale_mA =

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

5

. Read offset current with the meter and calculate:

6

4000

Reading[mA]

AoutOffset_mA = -FlowOutScale_mA*Offset_Reading[mA]

. Save AoutScale_mA in to the EEPROM: !11,MW,27,Y[CR]

7

ave AoutOffset_mA in to the EEPROM: !11,MW,28,Z[CR]

S

OTICE

N

ull scale flow range (see the device’s front label). There is no need to perform

f
analog output calibration unless the EEPROM IC was replaced or offset/span

djustment is needed. Any alteration of the analog output scaling variables in the

a

as independent table will VOID calibration warranty supplied with instrument.

G

OTICE

N

software includes an automated calibration procedure which may radically
simplify calculation of the offsets and spans variables and, the reading and writing
for the EEPROM table.It is recommended to use the Dwyer 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, the reading and writing for the EEPROM table.

Index Name Description

25 AoutScaleV - DAC 0 to 5 VDC Analog Output Scale
27 AoutScale_mA - DAC 4 to 20 mA Analog Output Scale
28 AoutOffset_mA - DAC 4 to 20 mA Analog Output Offset

7.3.1 Initial Setup

Power up the Mass Flow Meter for at least 15 minutes prior to commencing the
calibration procedure. Make sure absolutely no flow takes place through the
meter. Establish digital RS-485/RS-232 communication between PC
(communication terminal) and GFM2. The commands provided below assume that
calibration will be performed manually (w/o Dwyer supplied calibration and
maintenance software) and the device has RS-485 address 11. If Dwyer supplied
calibration and maintenance software is used, skip the next section and follow the
software prompts.

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]
Unit will respond with: !11,DisableUpdate: D

The analog output available on the GFM2 Digital Mass Flow

eter was calibrated at the factory for the specified gas and

M

It is recommended to use the Dwyer supplied calibration and
maintenance software for analog output calibration. This

Where: Y – the calculated AoutScale_mA value

Z – the calculated AoutOffset_mA value

NOTICE

command below).

Enable DAC update by typing: !11,WRITE,4,N[CR]
Unit will respond with: !11,DisableUpdate: N
Close BackDoor access by typing: !11,MW,1000,0[CR]
Unit will respond with: !11,BackDoorEnabled: N

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

8.1 General

The standard GFM2 comes with an RS-485 interface. For the optional RS-232
interface, the start character (!) and two hexadecimal characters for the address
must 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 (!). The command string is terminated with a carriage return (line feeds
are automatically stripped out by the GFM2). See section 2.2.3 for information
regarding communication parameters and cable connections.

8.2 Commands Structure

The structure of the command string:
!<Addr>,<Cmd>,Arg1,Arg2,Arg3,Arg4<CR>
Where:
! Start character.
Addr RS485 device address in the ASCII representation of

Cmd The one or two character command from the table below.
Arg1 to Arg4 The command arguments from the table below.

CR Carriage Return character.

hen done with the analog output calibration make sure the

W

AC update is enabled and the BackDoor is closed (see

D

hexadecimal (00 through FF are valid).

Multiple arguments are comma delimited.

7.3.2 Gas Flow 0 to 5 VDC Analog Output Calibration

1. Install jumpers J7A, J7B and J7C on the 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 1 (-) of the 15 pins D connector.

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

4. Read voltage with the meter and calculate:

AoutScaleV =

5. Save FlowOutScaleV in to the EEPROM: !11,MW,25,X[CR]

Where: X – the calculated AoutScaleV value.

20000

Reading[V]

NOTICE

RS-232 option.

Several examples of commands follow. All assume that the GFM2 has been
configured for address 18 (12 hex) on the RS485 bus:

1. To get current calibration tables: !12,G<CR>

2. To get current Alarm status: !12,A,R<CR>

3. To get a flow reading: !12,F<CR>

4. Set the high alarm limit to 85% of FS flow rate:

Page 9

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

The GFM2 will reply: !12,G 0 AIR<CR>
(Assuming Current Gas table is #0, calibrated for AIR )

The GFM2 will reply: !12,N<CR>
(Assuming no alarm conditions)

The GFM2 will reply: !12,50.0<CR>
(Assuming the flow is at 50% FS)

The GFM2 will reply: !12,AH85.0<CR>

!12,A,H,85.0<CR>

OTICE

N

ddress is sent, all devices on the RS-485 bus execute the command but do not

a

eply with an acknowledge message.

r

The global address can be used to change RS-485 address for a particular

evice with unknown address:

d

. Make sure only one device (which address must be changed) is connected to

1

he RS-485 network.

t

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

2
XX, the new hexadecimal address, can be [01 – FF].

8.3 ASCII Commands Set

ommand

C

ame

N

low

F

Diagnostic

oll Back

R
N2Feature

Gas Select

Auto Zero

Flow Alarms

Address 00 is reserved for global addressing. Do not assign,

he global address for any device. When command with global

t

o.

N

ommand

escription

D

equests the current flow sensor

R
reading in current EU.

Enable / Disable LCD

iagnostic messages (only

D

or LCD option).

f

equest current status of the

R
Diagnostic events, LED status and
LCD diagnostic mode
(enabled/disabled).

nable / Disable Roll back

E
to N2feature.

Selects one of the ten primary gas
calibration tables to use. Tables
are entered via the MEM
commands at time of calibration.

Starts /reads the status of the auto
zero feature (Note: The Z,N
command can be used only when
absolutely no flow thru the meter
and no earlier then 6 minutes after
power up. It can take several
minutes to complete. Unit will not
respond to other commands when
this is in progress).
Sets / reads the status of the gas
flow alarms.
Note: High and Low limits have to
be entered in the % FS. High
alarm value has to be more than
Low
alarm value.
Alarm conditions:
Flow > High Limit = H
Flow < Low Limit = L
Low < Flow < High = N

C

1

F

2

D

3

N

4

G

5

Z

6

A

rgument 1

A

E (enable LCD
Diagnostic

essages)

M

(disable LCD

D

iagnostic

D
Messages)
NO ARGUMENT
(read current status
of the diagnostic

ord)

w
E

enable Roll back to

(
N2)
D
(enable Roll back to
N2)
NO ARGUMENT
(read current mode
of the N2Roll back )
0 (gas 0) to
9 (gas 9)
NO ARGUMENT
(read status)
N (do it now)
W (Write Zero to
EEPROM)
S (Status while auto
zero in progress)
V (Display zero
value)

H (high flow limit)

L (low flow limit)

A (action delay in
seconds)
E (enable alarm)
D (disable alarm)
R (read current
status)

S (read current
status)

B Block (Latch)
mode

fter assigning the new address, a device will accept commands with the new

A

ddress.

a

OTICE

N

he same address are connected to the one RS-485 network, a communication

t

ollision will take place on the bus and communication errors will occur.

c

rgument 2

A

<Value> (0 to
100%FS)
<Value> (0 to
100%FS)
<Value> (0 to
3600 sec)

<Value>
(0-disabled)
(1-enabl’d L)
(2-enabl’d H)
(3-both L,H)

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

rgument 3 Argument 4 Response

A

Value> (Actual flow in

<
current engineering
units)
D:E

:D

D

D:0x0,L:9,E
0x0 – diagnostic word
9 - current LED status

- LCD mode (enabled)

E

:E

N

N:D

N:D or
N:E

G0 through G9,
<Gas Name>
G0 through G9,
<Gas Name>
ZN
ZW (when done)

ZNI,<value> while Z, N
is in progress
ZV, <zero value>

AH <Value>

AL <Value>

AA: <Value>

AE
AD
N - (no alarm)
H - (high alarm)
L - (low alarm)
AS:M,L,H,D,B where:
M – mode (E/D)
L – Low settings (%FS)
H – High settings (%FS)
D – Action Delay (sec)
B – Latch mode (0-3)
AB:<Value> where:
Value = 0 - 3

Page 10

ommand

C

ame

N

elay Action

R

otalizer

T

-Factors

K

Units

escription

D

ssigns action of the two SPDT

A

elays. The coil is energized

r
when the condition specified by
an Argument 2 becomes true.
Argument 2:

- no action, relay disabled

N

- totalizer reading > limit

T

- high flow alarm

H

- low flow alarm

L
R - Range between High &
Low alarms
M - Manual Relay overdrive

- Read current status

S

ets and controls action of the

S

low totalizer.

f
NOTE: If Warm Up Delay option
is set to E (enabled) the Totalizer
will not totalize the flow during
first 6 minutes after power up.

pplies a gas correction factor to

A

he currently selected primary gas

t

alibration table.

c
(NOTE: does not work with %FS
engineering unit.)
See list of the internal K-factors in
the operating manual.

Set the units of measure for gas
flow and totalizer reading.
Note: The units of the totalizer
output are not per unit time.

rgument 4

rgument 3

rgument 2

o.

N

ommand

C

7

R

rgument 1

A

(relay 1)

1
2 (relay 2)

A

N
T

A

A

H
L
R
M
S

8

T

(reset to zero)

Z

(start totalizer at

F
flow FS)
L (limit gas volume
in current EU)

value> (flow

<
%FS)
<value> (gas
volume)

D (disable totalizer)

(enable totalizer)

E

(read current

R

otalizer volume)

t
W (warm up delay)

E - enable

esponse

R

1N or R2N

R
R1T or R2T
R1H or R2H
R1L or R2L

1R or R2R

R

1M or R2M

R

xN, RxT, RxH, RxL,

R

xR, RxM

R

Z

T

F<value>

T

TL<value>

TD

E

T

value>(in current EU)

<

TW:E or TW:D

D - disable

S: Mode, Start, Limit,

(setting status)

S

T
Warm Up

9

K

D (disable, sets

KD
K=1)
I (internal K-factor)

U (user specified
factor)

No argument

enable

(

reviously set

p

nternal K-factor)

i
Gas Index (0-35)
No argument
(enable

KI,<value>,<Gas>

KI,<Index>,<Gas>

KU,<value>

previously set
user K-factor)
<value> (decimal

KU,<value>

correction factor)
(0-1000)

S (status)

SK, <Mode>, <Index>,

<Value> where:

Mode: D, I, U

Index: 0-35

Value: K-Factor value

10

U

% (%FS)
mL/sec
mL/min
mL/hr
L/sec
L/min
L/hr

3

m

/sec

3

m

/min

3

m

/hr

3

f

/sec

3

f

/min

3

f

/hr
g/sec
g/min
g/hr
kg/sec
kg/min
kg/hr
Lb/sec
Lb/min
Lb/hr
USER (user
defined)

<value>
(conversion factor
from L/min)

S - seconds
M – minutes
H – hours (Time

Y - use density
N – do not use
density

U:%
U:mL/sec
U:mL/min
U:mL/hr
U:L/sec
U:L/min
U:L/hr

3

U:m

/sec

3

U:m

/min

3

U:m

/hr

3

U:f

/sec

3

U:f

/min

3

U:f

/hr
U:g/sec
U:g/min
U:g/hr
U:kg/sec
U:kg/min
U:kg/hr
U:Lb/sec
U:Lb/min
U:Lb/hr
U:USER,<Factor>,
<Time base>,
<Density mode>

base)

No Argument

U,<EU name>

<status> Returns
current EU

Page 11

Command
Name

Maintenance

imer

T

ull Scale

F

LCD Back
Light

ead

R
EEPROM
Memory
Write

EPROM

E

emory

M

ART Error Codes:

U

- Not Supported Command or Back Door is not enabled.

1
2 - Wrong # of Arguments.
3 - Address is Out of Range (MR or MW commands).

- Wrong # of the characters in the Argument.

4
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 - Reserved.

- Manufacture specific info EE KEY (wrong key or key is disabled).

9

Description

Hours since last time unit was

alibrated.

c

eturns the full scale rated flow in

R

/min. (Note: This term is not

L
multiplied by the current K factor)

LCD Back Light control

0-100.0%)

(

- off

0

00 - Maximum Intensity

1

Reads the value in the
specified memory location.

rites the specified value to the

W

pecified memory location. Use

s

arefully, can cause unit to

C
malfunction. (Note: Some
addresses are write protected!)

No.

11

1

1

1

15

2

3

4

Command

C

E

B

R

M

MW

Argument 1

R (read timer)
C (set timer to zero)

to 100%

0

No Argument

current settings>

<

000 to 999

0

Table Index)

(

0000 to 999
(Table Index)

Argument 2

Value

. TROUBLESHOOTING

9

.1 Common Conditions

9

Your GFM2 Digital Mass Flow Meter was thoroughly checked at numerous quality
control points during and after manufacturing and assembly operations. It was

alibrated according to your desired flow and pressure conditions for a given gas

c
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 following common

onditions first:

c

re all cables connected correctly? Are there any leaks in the installation? Is the

A
power supply correctly selected according to requirements? When several meters
are used a power supply with appropriate current rating should be selected.

Argument 3 Argument 4 Response

<Value> (in Hours)
CC

Value> (in L/min)

<

:<Counts>

B
where:
Counts (0 – 4095)
B:<Value>

here:

w

alue (0 – 100.0)

V

value>

<

MW,XXX,<Value>
where:

XX=Table Index

X

9.2 Troubleshooting Guide

No.

Indication

1

No zero reading after 15 min. warm up time and
no flow condition.

2

Status LED indicator and LCD display remains
blank when unit is powered 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
VDC signal fluctuate in wide range during flow
measurement.

4

LCD display reading does correspond to the
correct flow range, but 0-5 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 volt age 0 to 5 VDC signal is
more than 5.0 VDC when gas flows through the
GFM2.

8

Gas flows through the GFM2, but LCD display
reading and the output voltage 0 to 5 Vdc signal
do not respond to flow.

Were the connector pinouts matched properly? When interchanging with other
manufacturers' equipment, cables and connectors must be carefully wired for
correct pin configurations. Is the pressure differential across the instrument
sufficient?

Likely Reason

Embedded temperature has been
changed.
Power supply is bad or polarity is
reversed.

PC board is defective.
Output 0-5 Vdc signal (pins 2–1 of the D­connector) is shorted on 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 is open or load resistance
more than 500 Ω.
Output 4 to 20 mA schematic is burned
out or damaged.
GFM2 has initial zero shift.

Sensor under swamping conditions (flow
is more than 10% above maximum flow
rate for particular GFM2).
PC board is defective.
The gas flow is too low for particular
model of GFM2.
GFM2 models: RFE is not connected
properly to the inlet fitting.
Sensor or PC board is defective.

Solution

Perform Auto Zero Procedure (see section 5.3.6 “Zero
Calibration”).
Measure voltage on pins 7 and 5 of the 15 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.
Return GFM2 to factory for repair.
Check external connections to pin 2 – 1, of the D-connector. Make
sure the load resistance is more than 1000 Ω.

Return GFM2 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 GFM2 to factory for repair.

Shut off the flow of gas into the GFM2 (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 5.3.7 “Zero Calibration”).
Lower the flow through GFM2 within calibrated range or shut down
the flow completely. The swamping condition will end automatically.

Return GFM2 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
Return GFM2 to factory for repair.

Page 12

o.

N

ndication

I

9

as does not flow through the GFM2 with inlet

G

ressure applied to the inlet fitting. LCD display

p
reading and output voltage 0 to 5 VDC signal
show zero flow.

10

Gas flows through the GFM2, output voltage 0 to

VDC signal does not respond to flow (reading

5

ear 1mV).

n

11

The Status LED indicator is rapidly flashing with
UMBER color on /off.

12

The Status LED indicator is rapidly flashing with

ED color on /off.

R

3

1

he Status LED indicator is rapidly flashing with

T

ED and UMBER colors.

R

14

The Status LED indicator is constantly on with
the RED light.

9.3 Technical Assistance

Dwyer Instruments will provide technical assistance over the phone to qualified
repair personnel. Please have your Serial Number and Model Number ready
when you call.

10. CALIBRATION CONVERSIONS FROM REFERENCE GASES

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

T

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

g

K

gas

where d = gas density (gram/liter)

Cp= coefficient of specific heat (cal/gram)

Note in the above relationship that d and Cp are usually chosen at the same
conditions (standard, normal or other).

1

=

d X C

p

Likely Reason

ilter screen obstructed at inlet.

F

Direction of the gas flow is reversed.

GFM2 is connected in the installation

ith back pressure conditions and gas

w

eak exist in the system.

l

ensor temperature is too low.

S

Sensor temperature is too high.

MCU temperature is too high (overload).

Fatal Error (EEPROM or Auto Zero
error).

Solution

lush clean or disassemble to remove impediments or replace the

F

ilter screen (see section 6.2). NOTE: Calibration accuracy can be

f

ffected.

a

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 GFM2 has internal leak

eturn it to factory for repair.

r

ake sure the ambient and gas temperatures are within specified

M

ange (above 5°C).

r
Make sure the ambient and gas temperatures are within specified
range (below 50°C).
Disconnect power from the GFM2. Make sure the ambient

emperature is within specified range (below 50°C). Let the device

t

ool down for at least 15 min. Apply power to the GFM2 and check

c

tatus LED indication. If overload condition will be indicated again the

S
unit has to be returned to the factory for repair.
Cycle the power on the GFM2. If Status LED still constantly on with
RED light, wait 6 min. and start Auto Zero function (see 5.3.7 Zero
Calibration). If after Zero Calibration the Fatal Error condition will be

ndicated again the unit has to be returned to the factory for repair.

i

If the flow range of a Mass Flow Meter remains unchanged, a relative K factor is
used to relate the calibration of the actual gas to the reference gas.

Q

K

a

=

K

where Qa= mass flow rate of an actual gas

Qr=

Ka= K factor of an actual gas
Kr = K factor of a reference gas

For example, if we want to know the flow rate of oxygen and wish to calibrate
with nitrogen at 1000 SCCM, the flow rate of the oxygen is:

Q

= Q

O

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

NOTICE

computations will be performed internally by MCU.

= Q

a

2

If particular K factor is activated via digital interface, the user
does not need to perform any conversion. All conversion

Q

sccm)

(

mass flow rate of a reference gas

sccm)

(

x K = 1000 X 0.9926 = 992.6 sccm

r

a

=

K

r

r

Page 13

No.

Indication

0

BlankEEPROM

1

erialNumber

S

2

odelNumber

M

3

oftwareVer

S

4

imeSinceCalHr

T

5

Options1

6

BackLight

7

AddressRS485

8

asNumber

G

9

lowUnits

F

0

1

larmMode

A

11

owAlarmPFS

L

12

HiAlarmPFS

13

AlmDelay

4

1

RelaySetting

5

1

otalMode

T

6

1

otal

T

17

otalFlowStart

T

18

TotalVolStop

19

KfactorMode

20

KfactorIndex

1

2

UserDefKfactor

2

2

DUnitKfactor

U

3

2

DUnitTimeBase

U

24

DUnitDensity

U

25

AoutScaleV

26

DRC_DP

27

AoutScale_mA

8

2

AoutOffset_mA

29

SensorZero

30

Klag [0]

31

Klag [1]

32

Klag [2]

33

Klag [3]

34

Klag [4]

35

Klag [5]

36

Kgain [0]

37

Kgain [1]

38

Kgain [2]

39

Kgain [3]

40

Kgain [4]

41

Kgain [5]

42

Zero_T

43

Tcor_K

44

AlarmLatch

45

TotalWarmDisable

46

Reserved1

47

LCD_Diagnostic

48

Reserved2

49

N2_RollBack

50

Reserved3

PPENDIX I

A

®

wyer

D

FM2 EEPROM Variables Rev. A0

G

Gas Independent Variables

Data Type

char[10]

har[20]

c

har[20]

c

har[10]

c

loat

f
uint
int
char [4]

nt

i

nt

i

har

c

loat

f
float
uint
char [4]

har

c

loat

f

loat

f
float
char
int
float

loat

f

nt

i

har

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

Notes

Do not modify. Table Revision. [PROTECTED]

erial Number [PROTECTED]

S

odel Number [PROTECTED]

M

irmware Version [PROTECTED]

F

ime since last calibration in hours

T
Misc. Options
Back Light Level [0-4095]
Two character adress for RS485 only

urrent Gas Table Number [0 - 9]

C

urrent Units of Measure [0 - 22]

C

larm Mode [‘E’ - Enabled, ‘D’ - Disabled]

A

ow Flow Alarm Setting [%FS] 0 - Disabled

L
High Flow Alarm Setting [%FS] 0 - Disabled
Flow Alarm Action Delay [0 - 3600 sec] 0 - Disabled
Relays Assignment Setting (N, T, H, L, R, M)

otalizer Mode [‘E’ - Enabled, ‘D’ - Disabled]

T

otalizer Volume in %*s (updated every 6 min)

T

tart Totalizer at Flow [%FS] 0 - Disabled

S
Totalizer Action Limit Volume [%*s] 0 - Disabled
D-Disabled, I-Internal, U-User Defined
Internal K-Factor Index [0 - 35]
User Defined K-Factor

-Factor for User Defined Units of Measure

K

ser Defined Unit Time Base [1, 60, 3600 sec]

U

ser Defined Unit Density Flag [Y, N]

U
DAC 0 to 5 VDC Analog Output Scale
H/W DRC DP settings [0-255]
DAC 4 to 20 mA Analog Output Scale
DAC 4-20mA Analog Output Offset
DPW value for Sensor Zero [0-1023]
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]
Gain for DRC Lag Constant [Do Not Alter]
Gain for DRC Lag Constant [Do Not Alter]
Gain for DRC Lag Constant [Do Not Alter]
Gain for DRC Lag Constant [Do Not Alter]
Resistance when last AutoZero was done [0-4095 count]
Resistance correction coefficient [PFS/count]
Alarm Latch [0-3]
Sensor Warm Up period Totalizer [D/E]
Reserved
LCD Diagnostic Mode: [E/D]
Flow Reading Averaging: [0,1,2] (100, 250, 1000 ms), Default -1
Back to N2 conversion mode: [E, D]
Reserved for Troubleshooting (do not change)

Page 14

ndex

I

Name

00

1

asIndentifier

G

01

1

ullScaleFlow

F

02

1

tdTemp

S

103

tdPressure

S

104

StdDensity

105

CalibrationGas

06

1

alibratedBy

C

07

1

alibratedAt

C

08

1

ateCalibrated

D

109

ateCalibrationDue

D

110

K_N

111

K_F1

12

1

K_F1

13

1

ensorTbl[0][Sensor Value]

S

14

1

ensorTbl[0][Flow]

S

115

ensorTbl[1][Sensor Value]

S

116

SensorTbl[1][Flow]

117

SensorTbl[2][Sensor Value]

118

SensorTbl[2][Flow]

19

1

SensorTbl[3][Sensor Value]

20

1

ensorTbl[3][Flow]

S

21

1

ensorTbl[4][Sensor Value]

S

122

ensorTbl[4][Flow]

S

123

SensorTbl[5][Sensor Value]

124

SensorTbl[5][Flow]

125

SensorTbl[6][Sensor Value]

26

1

SensorTbl[6][Flow]

27

1

ensorTbl[7][Sensor Value]

S

28

1

ensorTbl[7][Flow]

S

129

ensorTbl[8][Sensor Value]

S

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.

NOTICE

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

Index

0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35

Calibration Table

Gas Dependent Variables

Data Type

har[20]

c

loat

f

loat

f

loat

f
float
char[20]

Notes

N
F
S
S
Gas Standard Density
Name of Gas used for Calibration
[If not calibrated = ‘Uncalibrated’]

har[20]

c

har[20]

c

har[12]

c

har[12]

c

2

float
float
float

int

u

loat

f

int

u
float
uint
float
uint

loat

f

int

u

loat

f
uint
float
uint
float

int

u

loat

f

int

u
float
uint
float
uint
float

N
N
C
D
Gas Parameters: K-factor relative to N
Reserved
Reserved

ndex 0: Must be 120 (zero value) Do not Alter!

I

ndex 0: Must be 0.0 (zero PFS) Do not Alter!

I
1
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]
A
4
A

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]
7
A
8
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!

APPENDIX II - Internal “K” Factors

Actual Gas

Acetylene C
Air
Allene (Propadiene) C
Ammonia NH
Argon Ar
Arsine AsH
Boron Trichloride BCl
Boron Trifluoride BF
Bromine Br
Boron Trobromide Br
Bromine PentaTrifluoride BrF
Bromine Trifluoride BrF
Bromotrifluoromethane CBrF
1,3 - Butadiene C4H
Butane C4H
1 - Butene C4H
2 - Butene C4H8 CIS
2 - Butene C
Carbon Dioxide CO
Carbon Disulfide CS
Carbon Monoxide C
Carbon Tetrachloride CCl
Carbon Tetrafluoride (Freon-14) CF
Carbonyl Fluoride COF
Carbonyl Sulfide COS
Chlorine Cl
Chlorine Trifluoride CIF
Chlorodifluoromethane (Freon-22) CHCIF
Chloroform CHCl
Chloropentafluoroethane (Freon-115) C2CIF
Chlorotrifluromethane (Freon-13) CCIF
Cyanogen C2N
Helium He
Hydrogen H
Hydrogen H2(> 100 L/min)
Oxygen O

2H2

3H4

3

3

2

2

2

10

2

4H8

3

3

3

5

3

3

6

8

TRANS

2

2

0

4

4

2

3

2

3

2

Page 15

ame of Gas [If not calibrated = ‘Uncalibrated’]
ull Scale Range in l/min
tandard Temperature
tandard Pressure

ame of person who performed actual calibration

ame of Calibration Facility

alibration Date

ate Calibration Due

2

0.0% FS A/D Value from Sensor [counts]

ctual Flow in PFS [0.3]

0.0% FS A/D Value from Sensor [counts]
ctual Flow in PFS [0.4]

0.0% FS A/D Value from Sensor [counts]
ctual Flow in PFS [0.7]

0.0% FS A/D Value from Sensor [counts]

Density

2

Cp
(Cal/g)

.4036
.240
.352
.492
.1244
.1167
.1279
.1778
.0539
.0674
.1369
.1161
.1113
.3514
.4007
.3648
.336
.374
.2016
.1428
.2488
.1655
.1654
.1710
.1651
.114
.1650
.1544
.1309
.164
.153
.2613

1.241

3.419

3.419
.2193

(g/l)

1.162

1.293

1.787
.760

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

3.397

1.250

6.860

3.926

2.945

2.680

3.163

4.125

5.326

5.326

6.892

4.660

3.322
.1786
.0899
.0899

1.427

K-Factor
Relative to N

.5829

1.0000
.4346
.7310

1.4573
.6735
.4089
.5082
.8083
.38
.26
.3855
.3697
.3224
.2631
.2994
.324
.291
.7382
.6026

1.00
.31
.42
.5428
.6606
.86
.4016
.4589

2

.3912
.2418

2

.3834
.61

1.454

1.0106

1.92
.9926

NOTICE

APPENDIX III - Gas Factor Table (“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

D

ndex

I

Actual Gas

0

cetylene C

A

1

ir

A

2

llene (Propadiene) C

A

3

mmonia NH

A

4

Argon Ar (<= 10 L/min)

2H2

3H4

3

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

5

Arsine AsH

6

oron Trichloride BCl

B

7

oron Trifluoride BF

B

8

romine Br

B

9

oron Trobromide Br

B

10

Bromine PentaTrifluoride BrF

11

Bromine Trifluoride BrF

2

1

Bromotrifluoromethane (Freon-13 B1) CBrF

3

1

,3 - Butadiene C

1

14

utane C

B

15

1 - Butene C4H

16

2 - Butene C4H8 CIS

17

2 - Butene C

8

1

Carbon Dioxide CO
C

9

1

C

20

Carbon Monoxide C0

1

2

Carbon Tetrachloride CCl

2

2

C

3

2

C

24

C

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

36

Dibromodifluoromethane CBr2F

37

Dichlorodifluoromethane (Freon-12) CCl2F

38

Dichlofluoromethane (Freon-21) CHCl2F

39

Dichloromethylsilane (CH

40

Dichlorosilane SiH2Cl

41

Dichlorotetrafluoroethane (Freon-114) C2Cl2F

42

1,1-Difluoroethylene (Freon-1132A) C2H2F

43

Dimethylamine (CH3)2NH

44

Dimethyl Ether (CH

45

2,2-Dimethylpropane C

46

Ethane C2H

47

Ethanol C2H6O

48

Ethyl Acetylene C

49

Ethyl Chloride C2H5Cl

50

Ethylene C

51

Ethylene Oxide C2H4O

52

Fluorine F

53

Fluoroform (Freon-23) CHF

54

Freon-11 CCl3F

55

Freon-12 CCl

56

Freon-13 CClF

57

Freon-13B1 CBrF

58

Freon-14 CF

59

Freon-21 CHCl2F

60

Freon-22 CHClF

61

Freon-113 CCl2FCClF

62

Freon-114 C2Cl2F

63

Freon-115 C2ClF

64

Freon-C318 C4F

65

Germane GeH

66

Germanium Tetrachloride GeCl

67

Helium He (<50 L/min)

3

2

4H10

arbon Dioxide CO
arbon Disulfide CS

arbon Tetrafluoride (Freon-14) CF
arbonyl Fluoride COF
arbonyl Sulfide COS

2

2H4

2

4H8

2

6

2F2

4

8

TRANS

3

2

3H5

6

3

2

5

8

4

3

3

3

3

4H6

(<10 L/min)

2

1 (<10 L/min)

-

2

2

2

3

2

O

3)2

3H12

4H6

3

2

4

4

3)2

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

SiCl

3

K-Factor
Relative to N

5829

.

.0000

1

4346

.

7310

.

1.4573

1.205
.6735

4089

.

5082

.

8083

.

38

.

5

.26
.3855
.3697

3

3224

.

2631

.
.2994
.324
.291
.7382

658

.

6026

.

1.00
.31

42

4

.

5428

.

6606

.
.86
.4016
.4589

2

.3912
.2418

5

.3834

3

.61
.6130
.4584

1.00
.4357

6

2

.1947
.3538

2

.4252
.2522
.4044
.2235

4

.4271

2

.3714
.3896
.2170
.50
.3918
.3225
.3891
.60
.5191
.9784
.4967
.3287
.3538
.3834
.3697
.4210
.4252
.4589
.2031
.2240
.2418
.1760
.5696

4

.2668

1.454

2.43

2.05

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
.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

g/l)

(

1.162

1.293

1.787
760

.

.782

1

.782

1

.478

3

5.227

3.025

7.130

1.18

1

.803

7

.108

6

6.644

2.413

2.593

2.503

.503

2

.503

2

.964

1

1.964

3.397

1.250

6.860

.926

3

.945

2

.680

2

3.163

4.125

3.858

5.326

6.892

4.660

2.322

2.742

1.877

1.799

1.235

9.362

5.395

4.592

5.758

4.506

7.626

2.857

2.011

2.055

3.219

1.342

2.055

2.413

2.879

1.251

1.965

1.695

3.127

6.129

5.395

4.660

6.644

3.926

4.592

3.858

8.360

7.626

6.892

8.397

3.418

9.565

.1786
.1786
.1786

Page 16

ndex

I

ctual Gas

A

8

6

exafluoroethane C

H

9

6

exane C

H

70

H
Hydrogen H
Hydrogen H

1

7

Hydrogen Bromide HBr

2

7

H

3

7

H

4

7

H

75

H

76

Hydrogen Selenide H

77

Hydrogen Sulfide H

8

7

Iodine Pentafluoride IF

9

7

I

0

8

I

1

8

K

82

Methane CH
Methane CH

3

8

Methanol CH

4

8

M

5

8

M

86

M

87

Methyl Fluoride CH

88

Methyl Mercaptan CH

89

Methyl Trichlorosilane (CH

90

M

91

Monoethylamine C2H5NH

92

Monomethylamine CH3NH

93

Neon NE

4

9

Nitric Oxide NO

5

9

N

6

9

N

97

Nitrogen Trifluoride NF

98

Nitrosyl Chloride NOCl

99

Nitrous Oxide N

100

Octafluorocyclobutane (Freon-C318) C

101

Oxygen O

102

Oxygen Difluoride OF

103

Ozone

104

Pentaborane B

105

Pentane C5H

106

Perchloryl Fluoride ClO3F

107

Perfluoropropane C

108

Phosgene COCl

109

Phosphine PH

110

Phosphorous Oxychloride POCl

111

Phosphorous Pentafluoride PH

112

Phosphorous Trichloride PCl

113

Propane C3H

114

Propylene C3H

115

Silane SiH

116

Silicon Tetrachloride SiCl

117

Silicon Tetrafluoride SiF

118

Sulfur Dioxide SO

119

Sulfur Hexafluoride SF

120

Sulfuryl Fluoride SO2F

121

Tetrafluoroethane (Forane 134A) CF3CH2F

122

Tetrafluorohydrazine N2F

123

Trichlorofluoromethane (Freon-11) CCl3F

124

Trichlorosilane SiHCl

125

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

6H14

ydrogen H

1 (<10-100 L)

-

2

-2 (>10-100 L)

2

-3 (>100 L)

2

ydrogen Chloride HCl
ydrogen Cyanide HCN
ydrogen Fluoride HF
ydrogen Iodide HI

sobutane CH(CH
sobutylene C

rypton Kr

ethyl Acetylene C

4H6

(<=10 L/min)

4

-1 (>=10 L/min)

4

3

ethyl Bromide CH
ethyl Chloride CH

olybdenum Hexafluoride MoF

itrogen N

2

itrogen Dioxide NO

2

12

8

4

(Freon-113) CCl2FCClF

126

Triisobutyl Aluminum (C4H9)AL

127

Titanium Tetrachloride TiCl

128

Trichloro Ethylene C2HCl

129

Trimethylamine (CH3)3N

130

Tungsten Hexafluoride WF

131

Uranium Hexafluoride UF

132

Vinyl Bromide CH2CHBr

133

Vinyl Chloride CH2CHCl

134

Xenon Xe

3

5H9

6

(

2F6

Se

2

S

2

5

3)3

3H4

r

B

2

l

C

3

F

3

SH

3

2

3

O

2

2

3F8

2

4

2

6
2

3

2

Freon-116)

)SiCl

3

3

6

2

2

3

5

3

4

4

4

3

6

6

4F8

K-Factor

elative to N

R

2421

.

1792

.

.0106

1

1.35

1.9

1.000
.000

1

764

.

9998

.

9987

.
.7893
.80
.2492

27

.

2951

.

.453

1
.7175
.75
.5843

4313

.

5835

.

6299

.
.68
.5180
.2499

2126

.
.3512
.51

1.46

.990

.000

1

737

.
.4802
.6134
.7128
.176
.9926
.6337
.446
.2554
.2134
.3950
.174
.4438
.759
.36
.3021
.30
.35
.40
.5982
.284
.3482
.69
.2635
.3883
.5096
.3237
.3287
.3278
.2031

.0608
.2691
.32
.2792
.2541
.1961
.4616
.48

1.44

2

Cp

Cal/g)

(

1834

.

3968

.

.419

3

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
.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)

(

.157

6

.845

3
.0899
.0899
.0899

.610

3

.627

1

.206

1

893

.

5.707

3.613

1.520
.90

9

.593

3

.503

2

.739

3
.715
.715

1.429
.787

1

.236

4

.253

2

1.518

2.146

6.669

9.366
.011

2

.386

1

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

4.418

1.517

6.843

5.620

6.127

1.967

1.877

1.433

7.580

4.643

2.858

6.516

4.562

4.224

4.64

6.129

6.043

8.36

8.848

8.465

5.95

2.639

13.28

15.70

4.772

2.788

5.858

Page 17

APPENDIX IV - Component Diagram

Top Component Side

Bottom Component Side

Page 18

PPENDIX V

PROCESS CONNECTION
(COMPRESSION FITTINGS
ATTACHED)

4

-29/64

[

112.97]

3

-5/32

[

80.16]

1-1/8

[28.70]

5

-5/16

[

134.88]

MASS FLOW METER

SERIES GFM2A

FLOW

A

imensional Drawings

D

APPENDIX VI
MAINTENANCE/REPAIR

Upon final installation of the Series GFM3, no routine maintenance is required. The Series GFM3 is not field serviceable and should be returned if repair is needed. Field
repair should not be attempted and may void warranty (See 1.3).

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.

Page 19

Page 20

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DWYER INSTRUMENTS, INC.

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

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