Sierra 780 Series User manual

Series 780-CT Instruction Manual Table of Contents
0-1
Sierra Series 780
Custody Transfer
Mass Flow Monitoring System
Instruction Manual
Part Number IM-78-CT
10.97 Revision B
5 Harris Court, Building L Monterey, CA 93940
[phone] [phone] Fax [phone]
http://www.sierrainstruments.com
Sierra Instruments b.v. Bolstoen 30A 1046 AV Amsterdam The Netherlands
31(0)20-6145810 Fax [phone]

Table of Contents Series 780-CT Instruction Manual
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Customer Notice
Unless you have specifically ordered Sierra’s optional O2cleaning, this flow meter
may not be fit for oxygen service. Sierra Instruments, Inc., is not liable for any dam-
age or personal injury, whatsoever, resulting from the use of Sierra Instruments
standard mass flow meters for oxygen gas. You are responsible for cleaning the
mass flow meter to the degree required for your oxygen flow application.
© COPYRIGHT SIERRA INSTRUMENTS 1997
No part of this publication may be copied or distributed, transmitted, transcribed, stored in
a retrieval system, or translated into any human or computer language, in any form or by
any means, electronic, mechanical, manual, or otherwise, or disclosed to third parties
without the express written permission of Sierra Instruments. The information contained in
this manual is subject to change without notice.
TRADEMARKS
Steel-TrakTM Collector-BoxTM and Flo-BoxTM are trademarks of Sierra Instruments Inc.
Other product and company names listed in this manual are trademarks or trade
names of their respective manufacturers.

Series 780-CT Instruction Manual Table of Contents
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Table of Contents
Chapter 1 Introduction
Series 780-CT Mass Flow Monitoring System ....................1-1
Using this Manual.................................................1-1
Notes and Safety Information....................................1-1
Receipt of System Components .................................1-2
Technical Assistance..............................................1-2
How the Flow Monitoring System Works..........................1-3
Series 780-CT Mass Flow Meter Features.....................1-4
Series 900 Collector-Box Features..............................1-4
Chapter 2 Installation
Installation Overview..................................................2-1
Installing the Flow Monitoring Components.......................2-1
Flow Meter Installation Requirements..........................2-2
Flow Meter Orientation...........................................2-3
Flow Meter Installation...........................................2-3
Collector-Box Installation........................................2-4
Wiring Connections ...................................................2-5
Collector-Box Input Power Wiring .............................2-5
Sensor Wiring .....................................................2-6
Collector-Box Outputs ................................................2-7
Chapter 3 Operating Instructions
Facility Start Overview................................................3-1
Collector-Box Controls and Indicators..............................3-1
Display Selections.................................................3-2
Totalizer Reset.....................................................3-3
MODE Selections..................................................3-3
Function Selections ...............................................3-4
Numeric Keypad ..................................................3-4
Alarm Acknowledge ..............................................3-5
Status LEDs........................................................3-5
Operating the Flow Monitoring System.............................3-6
First Time Start Up................................................3-6
System Configuration.................................................3-7
Configuration Procedure .........................................3-7
Access Code Information........................................3-11

Table of Contents Series 780-CT Instruction Manual
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Chapter 4 Validation and Maintenance Procedures
Field Validation Procedures ..........................................4-1
Sensor Test Procedures...........................................4-1
Electronic Test Procedures.......................................4-2
Entering Bias Factors..................................................4-4
Bias Factor Procedure ............................................4-5
Maintenance Procedures ..............................................4-6
Obtaining an RMA.....................................................4-7
Chapter 5 Troubleshooting
System Diagnostics....................................................5-1
Troubleshooting Procedures..........................................5-2
Appendix A Product Specifications
Specifications and Drawings .........................................A-1
List of Figures
1-1. Flow Monitoring System Block Diagram..................1-3
2-1. Correct Flow Meter Orientation.............................2-3
2-2. Collector-Box Mounting Dimensions ......................2-4
2-3. Flow Meter Wiring ...........................................2-6
2-4. Motherboard Terminal Block Layout/Output Wiring.....2-7
2-5. Relay Board Terminal Block Designations ................2-8
3-1. Collector-Box Front Panel Controls........................3-1
A-1. Collector-Box Critical Component Locations .............A-3
A-2. Collector-Box Standard Wiring.............................A-4
A-3. Collector-Box Optional Rack Mount Wiring ..............A-4
A-4. Digi-Bridge Board Critical Component Locations........A-5
List of Tables
2-1. Required Minimum Pipe Lengths for Installation.........2-2

Series 780-CT Instruction Manual Table of Contents
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Warnings and Cautions
Agency approval for hazardous location installations varies between flow
meter models. Consult the factory for specific flow meter approvals be-
fore any hazardous location installation. For explosion proof installations,
you must use solid metal conduit and follow NFPA (or your local code)
approved wiring methods.
All installation procedures must be performed with the power Off.
All maintenance operations must be performed with the power Off. Be-
fore attempting any maintenance, verify no pressure is present in the
line. Gas leaks are possible during probe maintenance. Make sure the
lines are completely purged before removing the probe.
Calibration must be performed by qualified personnel. Sierra Instru-
ments, Inc. strongly recommends that you return your flow meter to the
factory for calibration.
The flow meter requires four wiring connections; two for power and two
for signal. The flow meter is not a 24 VDC, 4-20 mA loop powered trans-
mitter.
For all flow meter installations, standard industrial wiring practices apply.
Local codes may require the use of conduit. In general, we recommend
the use of conduit as a good wiring practice.
Although the meter will indicate flow in the opposite direction, it is calibrated
with flow in the direction indicated on the label. Confirm the meter is in-
stalled with flow in the same direction as the label. Measuring flow opposite
the calibration direction will result in inaccurate readings.
Before applying power for the first time, make sure all wiring is in compli-
ance with the instructions listed in Chapter 2.
The electronics, sensors and interconnecting wires supplied by Sierra In-
struments are calibrated as a single precision mass flow meter. Each
component is an integral part of the flow measurement circuit. Changing
the length of wires or interchanging sensors or sensor wiring will affect
the accuracy of the flow meter.

Table of Contents Series 780-CT Instruction Manual
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Series 780-CT Instruction Manual Chapter 1 Introduction
1-1
Chapter 1 Introduction
Series 780-CT Mass Flow Monitoring System
The Sierra Series 780-Custody Transfer (CT) Mass Flow Monitor-
ing System precisely monitors the total accumulated mass flow of air
and process gases. The 780-CT Monitoring System features dual
level totalizing for tracking standard and premium flow rates. The
field-programmable totalizer automatically switches between normal
and premium billing rates based on the measured flow rate.
780-CT system components include a Sierra Series 780-CT Mass
Flow Meter with built in flow conditioning plates and a Sierra Series
900 Collector-Box™for computing totalized flow.
Using This Manual
This manual provides the information you need to install and operate
the 780-CT Mass Flow Monitoring System. The five chapters of
this manual cover these areas:
• Chapter 1 includes the introduction and product description
• Chapter 2 provides information needed for installation
• Chapter 3 describes system operation
• Chapter 4 covers system diagnostics and validation
• Chapter 5 outlines troubleshooting procedures
The product specifications and dimensional drawings are found in
Appendix A.
Note and Safety Information
We use note, caution and warning statements throughout this book
to draw your attention to important information.
Warning! Caution! Note
This statement appears with
information that is important to
protect people and equipment
from damage. Pay very close
attention to all warnings that
apply to your application.
This statement appears with
information that is important
for protecting your equipment
and performance. Read and
follow all cautions that apply
to your application.
This statement appears with
a short message to alert you
to an important detail.

Chapter 1 Introduction Series 780-CT Instruction Manual
1-2
Receipt of System Components
When receiving the components of the Sierra Flow Monitoring
System, carefully check the outside packing carton for damage in-
curred in shipment. If any carton is damaged, notify the local carrier
and submit a report to the factory.
Remove the packing slip and check that all ordered components are
present. Make sure any spare parts or accessories are not discarded
with the packing material. Do not return any equipment to the fac-
tory without a Return Material Authorization (RMA, see Chapter 4).
Technical Assistance
If you encounter a problem with your flow monitoring system, re-
view the configuration information for each step of the installation
and operation procedures. Verify that your settings and adjustments
are consistent with factory recommendations. Refer to Chapter 5,
Troubleshooting, for specific information and recommendations.
If the problem persists after following the troubleshooting proce-
dures outlined in Chapter 5, contact Sierra Instruments, Technical
Support at [phone] or [phone] between 8:00 a.m.
and 5:00 p.m. PST. When calling technical support, have the fol-
lowing information on hand:
•the flow meter serial number
•the Collector-Box serial number
•the flow range of the meter
•the software version number
•your Instruction Manual
•the problem you are encountering

Series 780-CT Instruction Manual Chapter 1 Introduction
1-3
How the Flow Monitoring System Works
Collector-Box
Series 780-CT
Mass Flow Meter
Series 900 Collector-Box
Flow Sensors
(Aligned 90-degrees to flow)
Heat
Gas Flow
Sensor Detail
Ts Ta
Figure 1-1. Flow Monitoring System Block Diagram
The 780-CT Mass Flow Meter measures gas flow using two sensing
elements–a velocity sensor and a temperature sensor that automati-
cally correct for changes in gas temperature. The digital sensor
bridge, Digi-bridge circuit heats the velocity sensor (Ts) at a con-
stant temperature differential above the gas temperature (Ta) and
measures the cooling effect of the gas flow. When heat is carried
away by the molecules in the gas, the heated sensor directly meas-
ures mass velocity (Ts-Ta), referenced to standard conditions of
70°F (21.1°C) and one atmosphere.
A supplied 5-wire cable connects between the flow meter sensor and
the Digi-bridge board inside the Collector-Box enclosure. This ca-
ble makes all the necessary power and signal connections.
Using data from the mass flow meter, the 900 Series Collector-Box
calculates the mass flow rate based on the power required to maintain
the constant temperature differential. The Collector-Box displays the
flow rate and totalized mass flow on a 2 x 16 digit LCD readout
screen. The Collector-Box provides both a 4-20 mA and 0-5 VDC
output signal proportional to mass flow.

Chapter 1 Introduction Series 780-CT Instruction Manual
1-4
Series 780-CT Mass Flow Meter Features
Series 780-CT mass flow meter bodies are constructed of 316L
stainless steel tubing. The 780 flow body incorporates special flow
conditioning plates welded into the body between the sensor and the
inlet connection. This unique dual-plate design eliminates velocity
profile distortions, swirl and temperature stratification in the gas
stream and greatly reduces upstream piping requirements.
Series 780-CT mass flow meters are available in a variety of process
connections depending on the flow meter ordered. Compression
fittings allow easy removal of the flow meter sensor probe for serv-
ice or maintenance procedures. The flow meter can be installed at a
remote location up to 350 feet from the Collector-Box.
Series 760HP/UHP and Series 780HP/UHP Mass Flow Meters are
also available with the Flow Monitoring System. The flow bodies
are constructed of 316L electropolished stainless steel tubing. The
“UHP” has a 7-10 Ra internal finish; the “HP” has 20-25 Ra. The
tubing’s smooth, level surface eliminates turbulence and erosive ac-
tion, which generates particulates. The Model 780HP/UHP flow
body incorporates flow conditioning plates that reduce upstream
piping requirements and improve measurement accuracy in con-
strained installations.
Series 900 Collector-Box Features
The Collector-Box’s flexible features allow you to customize your
flow monitoring and totalizing requirements. Local programming is
available via the 20-button, menu driven keypad along with the 2 x
16 character LCD display. The Collector-Box displays velocity,
standard volumetric flow, mass flow, total mass and time in user-
selectable engineering units. Comprehensive self-diagnostics, pro-
grammable testing and field calibration capabilities ensure accurate
flow rate monitoring.
The dual-totalizing feature allows you to set standard and premium
levels of flow monitoring. Pressing TOTAL on the front panel in-
terface displays the total units of flow. Press TOTAL a second time
to show the time elapsed. When pressing the TOTAL button a third
and fourth time, the same data is displayed for the premium level
totalizer showing the total premium flow and elapsed premium bill-
ing time.

Series 780-CT Instruction Manual Chapter 2 Installation
2-1
Chapter 2 Installation
Installation Overview
The Sierra Series 780-CT Flow Monitoring System installation is
simple and straightforward. Included in this chapter are these basic
installation procedures:
• Installing system components
• Wiring connections
• Collector-Box output connections
Installing the Flow Monitoring Components
Agency approval for hazardous location installations varies between
flow meter models. Consult the factory for specific flow meter ap-
provals before any hazardous location installation. The Collector-
Box is not approved by any testing agency for installation in a haz-
ardous location. For explosion proof installations, you must use the
optional explosion proof enclosure and solid metal conduit, and
follow the National Electric Code (or your local code) approved
wiring methods.
Before installation, check the flow meter label against line pressure,
temperature and gas composition. Verify the line pressure will not
exceed the flow meter’s maximum pressure and temperature ratings.
Before installing the system components, verify the installation site
allows for these considerations:
• minimum number of pipe diameters required upstream of the
flow meter sensor (see the table on the next page)
• connection from the Collector-Box to the flow meter sensor
using the supplied interface cable
Also, check your flow system for anomalies such as:
1. leaks
2. valves or restrictions in the flow path that could create disturbances
in the flow profile that might cause unexpected flow rate changes
3. heaters that might cause rapid excursions in temperature
Warning!
All installation
procedures must be
performed with the
power Off.

Chapter 2 Installation Series 780-CT Instruction Manual
2-2
Flow Meter Installation Requirements
In order to achieve accurate and repeatable performance, the mass
flow meter must be installed with the specified minimum length of
straight pipe upstream of the flow meter sensor. Use this table to
determine the piping requirements for your installation site.
Straight Pipe Length Required for Installation(1)
Piping Condition Series 780
Flow Meters Series 760UHP Flow Meters (2) Series 780UHP Flow Meters
Single 90° Elbow or T-Piece 1D 15D 1D
Reduction (4:1) 3D 15D 3D
Expansion (4:1) 5D 10D-45D 5D
After a control valve 3D 45D 3D
Two 90° Elbows (Same Plane) 3D 30D 3D
Two 90° Elbows (Different Planes) 5D 50D 5D
Notes:
(1) Number of diameter (D) of straight pipe required between upstream disturbance
and the flow meter.
(2) Requires 3D of straight pipe downstream of the flow meter.
Table 2-1. Required Minimum Pipe Lengths for Flow Meter Installation

Series 780-CT Instruction Manual Chapter 2 Installation
2-3
Flow Meter Orientation
When installing the flow meter, reference the flow direction label
attached to the flow body. Install the meter with the label pointing in
the same direction as gas flow. This ensures the sensors are cor-
rectly aligned at 90-degrees to the gas flow.
Install with arrow
on meter in same
direction as flow
When correctly installed,
sensor probes are
aligned 90° to flow
Figure 2-1. Correct Flow Meter Orientation
Flow Meter Installation
1. Turn off the process gas. Verify that the line is not pressurized.
2. Confirm that the installation site meets the minimum upstream
and downstream pipe diameter requirements.
3. Prepare the connection fitting in place on the gas line. (Fitting
components should be blown clean with filtered gas before use.)
4. For Ultra High Purity (UHP) flow meters, maintain a flow of at
least 2 slpm (0.1 scfm) of inert gas during installation to minimize
tubing contamination from environmental moisture and particles.
5. For UHP flow meters, open the transparent bag and remove the
flow meter. Remove the fitting-protection caps.
6. Seat the flow meter on the mating connections. Secure the proc-
ess connections. Refer to specific technical guides furnished by
fitting manufacturers for additional installation specifications.
7. Verify the integrity of the seal by appropriate helium leak-testing
procedures.
8. For UHP flow meters, turn the gas flow on, then off, 10 times
to remove any particles generated during installation. (The flow
rate used should equal the process flow specifications.)
9. Flow meter installation is complete.
Caution!
For proper operation, the
meter must be installed
with the correct orienta-
tion. Measuring flow that
is opposite the calibra-
tion direction will result
in inaccurate readings.
Caution!
When using toxic or corrosive
gases, purge the line with inert
gas for a minimum of four hours
at full gas flow before installing
the flow meter.

Chapter 2 Installation Series 780-CT Instruction Manual
2-4
Collector-Box Installation
Figure 2-2. Collector-Box Mounting Dimensions
To install the Collector-Box:
1. Mount the enclosure in an upright position in a dry, vibration-
free location out of direct sunlight. The ambient temperature
range should remain within 32°F to 122°F (0 to 50°C).
2. Position the LCD display where the screen will be comfortable
for viewing, usually about fifteen to twenty degrees below eye
level is sufficient.
3. Allow adequate clearance for the Collector-Box front panel to
swing open.
4. Make wiring connections.

Series 780-CT Instruction Manual Chapter 2 Installation
2-5
Wiring Connections
The interface cable supplied by Sierra Instruments makes all the nec-
essary connections between the Collector-Box and the 780-CT flow
meter. The connections are performed through a five position ter-
minal strip located inside the flow meter enclosure and a six position
connector on the Digi-bridge board located inside the Collector-Box
enclosure.
Do not shorten the length or replace the interface cable supplied by
Sierra Instruments. This cable is calibrated as an integral part of the
precision flow measurement circuit. Changes to the cable length or
cable substitution may impair the accuracy of the flow reading.
Collector-Box Input Power Wiring
Most Collector-Boxes are supplied with a standard three-prong AC
power plug. If your Collector-Box has a power cord, plug it di-
rectly into a wall outlet. If you want to connect AC input power di-
rectly to the Collector-Box terminals, remove the power cord and
follow these directions:
Optional Input Power Wiring
1. Turn off power. Verify the correct input power as shown on the
product label.
2. Release two latches on the Collector-Box to open the clear plas-
tic front panel.
3. Rotate the black latch on the internal panel 90-degrees. Swing
out the panel to expose the Collector-Box motherboard.
4. Locate TB2 on the motherboard. TB2
contains the input for AC power. Select
one of the available entry ports on the
Collector-Box enclosure for routing of
the input power.
5. Connect input power at TB2 per the
designation shown at right (10 watt
max).
Warning!
All wiring procedures
must be performed with
the power OFF.
Caution!
To prevent contact be-
tween low-level isolated
signals and hazardous
AC mains voltage, use a
separate entry port for the
flow meter interface cable.
Hot
Ground
Neutral
AC
MAIN
TB2
Collector-Box
Power Hookup

Chapter 2 Installation Series 780-CT Instruction Manual
2-6
Sensor Wiring
Use the supplied interface cable to connect between the flow meter
and the Collector-Box.
To connect the components:
1. Release two latches on the Collector-Box to open the clear plas-
tic front panel.
2. Rotate the black latch on the internal
panel 90-degrees. Swing out the front
panel to expose the components.
3. Plug the connector end of the interface
cable into location shown at right (TB1
on the Digi-bridge board)
4. Route the cable through a Collector-
Box port to the flow meter.
5. Locate and loosen the small set screw that locks the flow meter
dome lid in place. Unthread and remove the dome lid.
6. Route the cable through the flow meter wiring port. Connect the
five wires of the interface cable to the flow meter as shown below.
7. Replace dome lid and tighten set screw.
White
Red
Black
Brown
Green
Velocity Sensor
Temperature
Sensor
Flow Meter Wiring
(dome lid removed)
Figure 2-3. Flow Meter Wiring
TB2
TB1Digi-bridge Board
Plug in connector here
Collector-Box
Motherboard

Series 780-CT Instruction Manual Chapter 2 Installation
2-7
Collector-Box Outputs
0-5 VDC and 4-20 mA Output Signal
The Collector-Box is equipped with 0-5 VDC and 4-20 mA out-
put signals. The full scale flow value (represented by 5 VDC
and 20 mA) may be modified via the <CONF.> setup procedure
described in Chapter 3.
The 0-5 VDC output signal can drive a load resistance between 1,000
and 2,000 ohms. The output is available on the motherboard at TB1,
pin 13 (0-5 VDC Output) and TB1, pin 14 (Ground Return).
The 4-20 mA output signal can drive up to 500 ohms including
drops in the wire. The output is available on the motherboard at
TB1, pin 15 (4-20 mA Output) and TB1, pin 14 (Ground Return).
When using either output signal, always use TB1, pin 14 for the
signal return. The Collector-Box is not a loop powered device.
TB2 TB3 Relay Board
TB1
TB4 Relay Board
Analog Voltage Outputs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
0-5 VDC Output
GND Return
4-20 mA Output
TB1
Figure 2-4. Motherboard Terminal Block Layout and Output Wiring

Chapter 2 Installation Series 780-CT Instruction Manual
2-8
Relay Outputs
The Collector-Box has four relay outputs. The outputs are located
on two terminal blocks, TB3 and TB4, located on the motherboard
above and below TB1 (see Figure 2-3 for locations).
The relay outputs supply dry contacts and provide a Common,
Normally Open, and Normally Closed circuit rated for 5 A at
115/230 VAC and 0.5 A at 24 VDC.
The relays are energized when an alarm condition is active. The
fault, low and high flow alarm relays are latched and remain ener-
gized until the <ALARM ACKNOW.> button is pressed on the
Collector-Box front panel.
Normal relay operation is interrupted during a Calibration Error
(CE) Test. See Chapter 4 for more information on the CE Test.
TB3
C
NO
NC
Fault
Alarm
C
NO
NC
Totalizer
Alarm
C
NO
NC
C
NO
NC
High
Alarm
Low
Alarm
TB4
Relay Name COM1 NO1 NC1 Relay Label
Fault Alarm TB3-1 TB3-2 TB3-6 K1
Totalizer Alarm TB3-4 TB3-5 TB3-6 K2
Low Flow Alarm TB4-1 TB4-2 TB4-3 K3
High Flow Alarm TB4-4 TB4-5 TB4-6 K4
Figure 2-5. Relay Board Terminal Block Designations

Series 780-CT Instruction Manual Chapter 3 Operation
3-1
Chapter 3 Operating Instructions
Facility Start Overview
After installing the 780-CT Mass Flow Monitoring System, you are
ready to begin system operation. This chapter explains the operator
interface, the start up procedure and system configuration. It is im-
portant to follow the sequence of events as listed in this chapter:
1. Review the Collector-Box controls and indicators
2. Power and operate the flow monitoring system
3. Configure system parameters
In this chapter, text shown in <BRACKETS> indicates a button on
the Collector-Box front panel.
The Flow Monitoring System generates one primary linear output
signal (0-5 VDC and 4-20 mA) that is proportional to flow. This
analog signal is available on the Collector-Box motherboard at TB1.
The full scale value of the output signal is programmable via the
configuration procedure explained later in this chapter.
Collector-Box Front Panel Display/Keypad
The Collector-Box display/keypad interface allows you to set, adjust
and monitor system parameters and performance. A full range of
commands are available through the display/keypad. The features of
each operator key are described on the following pages.
1 2 3 4 5
678910
EscEnt
*
FUNCTIONS
F1 F2
F3 F4
DISPLAY
FLOW TOTAL ALARM
SIERRA
Collector-Box
SENSOR FAULT
RS485
HIGH ALARM
LOW ALARM
TOTALIZER ALARM
O
NO
F
F
ALARM
ACKNOW
MODE
Slow
Diag
Fast
Conf
Chg
Units
YES
NO
Figure 3-1. Collector-Box Front Panel Controls and Indicators

Chapter 3 Operation Series 780-CT Instruction Manual
3-2
DISPLAY Selections
FLOW
Pressing the <FLOW> button
displays the actual flow. Three
types of flow and eight differ-
ent engineering units are se-
lectable via the <CHANGE
UNITS> button.
1. Velocity
The available engineering units are SFPM (Standard Feet Per Min-
ute) and NMPS (Normal Meters Per Second).
2. Standard Volumetric Flow
Velocity multiplied by the flow body area yields standard volumetric
flow. Available engineering units are SCFM (Standard Cubic Feet
per Minute), SCFH (Standard Cubic Feet per Hour) , and NM3H
(Normal Cubic Meters per Hour).
3. Mass Flow
Standard volumetric flow can be further multiplied by the Gas Den-
sity (standard density) to arrive at mass flow. Available units for
mass flow are LB/M (Pounds per Minute), LB/H (Pounds per
Hour), and KG/H (Kilograms per Hour).
TOTAL
When pressing <TOTAL> on the front panel, the upper display line
indicates “Total 1 LBS” and the lower line shows the total value of
flow (in six digits).
When pressing the <TOTAL> button a second time, the upper line
displays “Total 1 Time” and the second line shows the value in
hours (to the thousandth) that Totalizer #1 has been counting since
the last reset.
Pressing the <TOTAL> button a third and fourth time displays the
same parameters for Totalizer #2.
By pressing <CHANGE UNITS> the displayed value is converted
between the available flow units: FT3, M3, LBS, KG.
The totalizer is backed up into nonvolatile EPROM every ten min-
utes. This backup preserves the totalized reading despite any power
interruptions and has an essentially unlimited storage time.
Type of Flow Units Displayed
1. Velocity SFPM or NMPS
2. Standard-
Volumetric Flow SCFM, SCFH, or NM3H
3. Mass Flow LB/M, LB/H or KG/H