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

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