Sierra Top-Trak 820 Series User manual

Series 820 Instruction Manual Table of Contents
IM-82-C 0-1
Sierra 820 Series
Top-Trakª Mass Flow Meters
Instruction Manual
Part Number IM-82
Revision C 06-99
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
[phone] Fax [phone]

Table of Contents Series 820 Instruction Manual
0-2 IM-82-C
Customer Notice
Sierra Instruments, Inc. is not liable for any damage or personal injury, whatsoever,
resulting from the use of Sierra Instruments standard mass flow meters or control-
lers for oxygen gas. You are responsible for determining if this mass flow meter or
controller is appropriate for your oxygen application. You are responsible for
cleaning the mass flow meter or controller to the degree required for your oxygen
flow application.
© COPYRIGHT SIERRA INSTRUMENTS 1994
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
Top-Trakª and Cal-Benchª are trademarks of Sierra Instruments, Inc. Other product and
company names listed in this manual are trademarks or trade names of their respective
manufacturers.
All Sierra products are Year 2000 compliant.

Series 820 Instruction Manual Table of Contents
IM-82-C 0-3
Table of Contents
Chapter 1 Introduction
Introduction.............................................................1-1
Using this Manual .................................................1-1
Safety Information.................................................1-2
Receipt of System Components..................................1-2
Technical Assistance ..............................................1-2
Top Trak Features......................................................1-3
The 820 Series Flow Sensing Principle .............................1-4
Chapter 2 Installation
Installation Overview ..................................................2-1
Installing the Transducer ..............................................2-2
Compression Fittings .............................................2-2
VCO Fittings .......................................................2-2
VCR Fittings .......................................................2-3
All 1/2-inch Size Connections....................................2-3
Wiring the Transducer.................................................2-4
Standard 0-5 VDC Output Signal Wiring.......................2-5
Optional 4-20 mA Output Signal Wiring........................2-5
Remote Display Installation...........................................2-6
Chapter 3 Operation
Transducer Operation..................................................3-1
Transducer Accuracy..............................................3-1
Referencing the Transducer to Non-Standard Conditions ....3-2
Transducer Over-Ranging ........................................3-2
Zero and Span Adjustments ......................................3-3
Chapter 4 Maintenance and Repair
Transducer Cleaning...................................................4-1
Flow Path Cleaning Model 822/824 .................................4-2
Inlet and Outlet Screens...........................................4-2
Laminar Flow Element............................................4-3
Flow Path Cleaning Model 826/827 .................................4-4
Laminar Flow Element............................................4-4
Flow Path Cleaning Model 822-S/824-S............................4-5
Laminar Flow Element............................................4-5
Sensor Cleaning and Inspection .................................4-8
Transducer Calibration ................................................4-9
Transducer Troubleshooting.................. ...................... 4-11
Returning Equipment to the Factory ............................... 4-12

Table of Contents Series 820 Instruction Manual
0-4 IM-82-C
Appendix A Conversion Formulas and Gas Tables
Appendix B Production Specifications
List of Figures
1-1. Top-Trak Features (Typical)..................................1-3
1-2. Flow Paths through the Transducer..........................1-4
1-3. Flow Measuring Principle.....................................1-4
2-1. Piping Requirements for 1/2-inch Size Connections.......2-3
2-2. Transducer D-Connector Pin Assignments .. ...............2-4
2-3. Standard 0-5 VDC Output Signal Wiring ...................2-5
2-4. Single Transducer Current Loop Connection...............2-5
2-5. Multiple Transducer Current Loop Connections ...........2-6
2-6. Mounting the Remote Display ................................2-6
4-1. Model 822/824 Flow Components...........................4-2
4-2. Correct LFE Position ..........................................4-3
4-3. Model 826/827 Flow Components...........................4-4
4-4. Low Flow Transducer LFE Cleaning........................4-5
4-5. Medium Flow Transducer LFE Cleaning ...................4-6
4-6. High Flow Transducer LFE Cleaning .......................4-7
4-7. Printed Circuit Board Component Locations ............. 4-10

Series 820 Instruction Manual Table of Contents
IM-82-C 0-5
Cautions
Caution! Only qualified personnel should install the transducer.
Caution! Do not supply +DC power at the D-connector while using a power supply at
the power jack. Both supplies may be damaged.
Caution! Operating a 12 VDC transducer at 24 VDC will cause equipment damage.
Caution! Only qualified personnel should perform transducer service, calibration or
troubleshooting procedures.
Caution! When using toxic or corrosive gases, purge the unit thoroughly with inert
dry gas before disconnecting from the gas line.
Caution! Printed circuit boards are sensitive to electrostatic discharge. To avoid dam-
aging the board, follow these precautions to minimize the risk of damage:
· before handling the assembly, discharge your body by touching a grounded,
metal object
· handle all cards by their edges unless otherwise required
· when possible, use grounded electrostatic discharge wrist straps when handling
sensitive components

Table of Contents Series 820 Instruction Manual
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Series 820 Instruction Manual Chapter 1 Introduction
IM-82-C 1-1
Chapter 1 Introduction
This instruction manual covers the installation, operation and main-
tenance of SierraÕs 820 Series product line including the following
Top-TrakªModels:
· 822 Mass Flow Meter with display (nylon flow body)
· 824 Mass Flow Meter without display (nylon flow body)
· 826 Hi-Flow Meter with display (aluminum flow body)
· 827 Hi-Flow without display (aluminum flow body)
· 822-S Mass Flow Meter with display (stainless steel flow body)
· 824-S Mass Flow Meter without display (stainless steel flow body)
SierraÕs Top-TrakªMass Flow Meters are designed for precise
measurement of gas mass flow. The 820 Series offers a broad range
of sizes and process connections for flexibility and versatility. The
primary standard calibration ensures starting point accuracy and
NIST traceability. The meterÕs 0-5 VDC or 4-20 mA output signal is
provided for recording, data-logging or control. The optional dis-
play reads the mass flow rate directly in engineering units or per-
centage of full scale.
Using This Manual
This manual is organized into four chapters:
· Chapter 1 includes the introduction and theory of operation
· Chapter 2 provides installation and wiring instructions
· Chapter 3 describes transducer operation and features
· Chapter 4 covers maintenance, calibration and troubleshooting
Gas tables and conversion formulas are found in Appendix A.
The product specifications and dimensional drawings are found
in Appendix B.
Throughout this manual, we use the word transducer as a generic
term to represent all models of SierraÕs 820 Series Top-Trak
Mass Flow Meters.

Chapter 1 Introduction Series 820 Instruction Manual
1-2 IM-82-C
Safety Information
Caution and warning statements are used throughout this book to
draw your attention to important information.
Warning! Caution!
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 per-
formance. Read and follow all cautions that ap-
ply to your application.
Receipt of System Components
When receiving a Sierra transducer, carefully check the outside
packing carton for damage incurred in shipment. If the carton is
damaged, notify the local carrier and submit a report to the factory or
distributor. Remove the packing slip and check that all ordered com-
ponents are present and match your specifications (as ordered).
Make sure any spare parts or accessories are not discarded with the
packing material. Do not return any equipment to the factory without
first contacting Sierra Customer Service.
Technical Assistance
If you encounter a problem with your transducer, review the configu-
ration information for each step of the installation, operation and set
up procedures. Verify that your settings and adjustments are consis-
tent with factory recommendations. Refer to Chapter 4, Trouble-
shooting, for specific information and recommendations.
If the problem persists after following the troubleshooting procedures
outlined in Chapter 4, contact Sierra Instruments by fax or by E-mail
(see inside front cover). For urgent phone support you may call (800)
866-0200 or [phone] between 8:00 a.m. and 5:00 p.m. PST.
In Europe contact Sierra Instruments bv at [phone]. When
contacting Technical Support, make sure to include this information:
· the flow range, serial number, Sierra order number and
model number (all marked on the transducer nameplate)
· the problem you are encountering and any corrective action
taken
· application information (gas, pressure, temperature, pipe and
fitting configuration)

Series 820 Instruction Manual Chapter 1 Introduction
IM-82-C 1-3
Top-Trak Features
Standard Top-Trak Mass Flow Meters require a 12 to 15 VDC exter-
nal power source (24 VDC input power optional). The transducerÕs
0 to 5 VDC output signal allows for flow recording, data-logging or
control. A 4 to 20 mA output signal is optionally available. Input
power and output signal connections are made via the 9-pin sub-type
D-connector located on the side of the transducer. An additional input
power jack is located just below the D-connector. (It is important to
connect input power at only one location.)
The transducer shown below is a typical example of a 822 Series
Top-Trak Mass Flow Meter. Other models may vary slightly in their
appearance but are operationally equivalent.
Figure 1-1. Top-Trak Features (Typical)

Chapter 1 Introduction Series 820 Instruction Manual
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The 820 Series Flow Sensing Principle
The operating principle of Top-Trak transducers is based on heat
transfer and the first law of thermodynamics. During operation
process gas enters the instrumentÕs flow body and divides into two
flow paths, one through the sensor tube, the other through the lami-
nar flow element bypass. The laminar flow bypass generates a pres-
sure drop, P1ÐP2, forcing a small fraction of the total flow to pass
through the sensor tube (m1).
Figure 1-2. Flow Paths through the Transducer
Two resistance temperature detector (RTD) coils around the sensor
tube direct a constant amount of heat (H) into the gas stream. In ac-
tual operation, the gas mass flow carries heat from the upstream coil
to the downstream coil. The resulting temperature difference (DT) is
detected by the RTD coils and gives the output signal. Since the
molecules of the gas carry away the heat, the output signal is linearly
proportional to gas mass flow.
Figure 1-3. Flow Measuring Principle

Series 820 Instruction Manual Chapter 2 Installation
IM-82-C 2-1
Chapter 2 Installation
Installation Overview
To ensure a successful installation, inlet and outlet tubing should be
clean and free from burrs or rims caused by cutting prior to plumb-
ing the transducer into the system. The protective caps covering the
inlet/outlet fittings should not be removed until immediately prior to
installation.
Before installing the transducer, verify the following:
1. Make sure the installation site meets the specific operating pa-
rameters recorded on the transducer’s nameplate. Each trans-
ducer is factory-configured for a specific gas and flow range. If
the operating pressure is more than 50 psi (3.4 bar) away from
the calibration pressure, it is advisable to return the unit to the
factory for re-calibration. (Adjusting zero may be sufficient to
remain within specification.)
2. Do not locate the transducer in areas subject to sudden tempera-
ture changes, moisture, drafts or near equipment radiating sig-
nificant amounts of heat. Make sure to allow adequate space for
cable connectors and wiring.
3. For 1/2-inch size inlet/outlet process connections on models 826
and 827 make sure the location meets the minimum number of
recommended pipe diameters upstream and downstream of the
transducer. A minimum of 5 inches (127 mm) upstream and 2-
1/2 inches (64 mm) downstream is always recommended. (not
necessary for other models)
4. Horizontal mounting is preferable. Vertical mounting is possible
with best results achieved when the factory calibration is specifi-
cally performed for vertical mounting. In vertical positions zero
shift will occur depending on the gas pressure at zero flow.
5. If the gas contains any particulate matter, install an in-line filter
prior to the transducer. Recommended filter size: 15 micron for
flows of 10 sccm to 30 slpm, 30 micron for above 30 slpm.
6. If a potential over-flow condition exists, insert a valve or critical
orifice in the line to limit flow to approximately 25 percent above
the full scale range of the meter.
7. Confirm that the transducer o-ring material is compatible with
the gas to be measured.
8. For remote displays, confirm the supplied cable is of sufficient
length to connect the components.

Chapter 2 Installation Series 820 Instruction Manual
2-2 IM-82-C
Installing the Transducer
Follow the installation instructions that apply to your transducer’s
process connection. For all 1/2-inch size process connections, observe
the piping recommendations given on page 2-3. Before operation, all
plumbing should be checked carefully for leaks and the transducer
purged with dry nitrogen.
Compression Fittings
1. Position the transducer with the flow direction arrow pointing
downstream in the direction of flow.
1. Verify the position of the front
and back ferrule. Insert the
tubing into the fitting. Make
sure that the tubing rests
firmly on the shoulder of the
fitting and that the nut is finger
tight. (Do not mix or inter-
change parts of tube fittings
made by different manufacturers.)
2. Hold the body steady with a backup wrench. For 1/2-
inch size, tighten the nut 1-1/4 turns from finger tight. For 1/8-
inch, 1/4-inch and 3⁄8-inch sizes, tighten only 3/4 turn from fin-
ger tight. Do not over-tighten!
3. Check the system’s entire flow path thoroughly for leaks. (Do
not use liquid leak detectors, instead monitor pressure decay.
Over-exposing the transducer to leak detector fluid may damage
the unit.)
VCO and VCR Fittings
1. Position the transducer with the flow direction arrow pointing
downstream in the direction of flow.
2. Install new o-rings compatible with the gas to be used. (Do not
mix or interchange parts of tube fittings made by different manu-
facturers.)
3. Hold the body steady with a backup wrench. Tighten
the nut finger tight and then 1/4 turn tighter with a wrench. Do
not over-tighten!
4. Check the system’s entire flow path thoroughly for leaks. (Do not
use liquid leak detectors, instead monitor pressure decay. Over-
exposing the transducer to leak detector fluid may damage the unit.)
Caution!
Only qualified
personnel should install
the transducer.

Series 820 Instruction Manual Chapter 2 Installation
IM-82-C 2-3
1/4 Inch Female NPT (standard on nylon flow bodies)
1. Position the transducer with the flow direction arrow pointing
downstream in the direction of flow.
2. Use a good quality paste pipe thread sealant.
Apply to the pipe threads.
3. Tighten the pipe no more than 1 turn past hand-tight.
Caution! Do not over-tighten,
damage to the instrument may result.
4. Check the system’s entire flow path thoroughly for leaks. (Do not
use liquid leak detectors, instead monitor pressure decay. Over-
exposing the transducer to leak detector fluid may damage the unit.)
1/2-Inch Size NPT Connections (Models 826,827 only)
1. Install a section of straight pipe at least ten pipe diameters in length
upstream of the transducer. Also, allow at least five pipe diameters
downstream for accurate operation. DO NOT use reducers. If the
preceeding components in the flow path create disturbances extend
the upstream pipe length.
2. Position the transducer with the flow direction arrow pointing
downstream in the direction of flow.
3. Tighten fittings until leak tight (refer to published standards for
specific recommendations).
4. Check the system’s entire flow path thoroughly for leaks. (Do not
use liquid leak detectors, instead monitor pressure decay. Over-
exposing the transducer to leak detector fluid may damage the unit.)
Figure 2-1.
Piping Requirements for all 1/2-Inch Size Process Connections

Chapter 2 Installation Series 820 Instruction Manual
2-4 IM-82-C
Wiring the Transducer
Standard Top-Trak™transducers require a 12 to 18 VDC power
supply (15 VDC nominal, 100 mA maximum). 24 VDC input power
is optional. Transducers are connected to the power supply through
either the dedicated DC power jack or through the 9-pin D-connector
located on the side of the enclosure. Before powering the unit, check
the transducer’s nameplate to confirm input power:
•PV1 = 12 to 18 VDC
•PV2 = 24 VDC
Note: operating a 24 VDC transducer at 12 to 18 VDC will result in
unreliable operation.
The transducer’s standard 0 to 5 VDC (4-20 mA optional) output
signal is available through the D-connector. The mating connector is
included with the transducer. Connection details are given on the
following pages.
When the transducer is configured for a remote display, signal con-
nections are made via the 9-pin connector. Input power connections
are not included in the standard interface cable. Remote display
mounting dimensions are given at the end of this chapter.
Figure 2-2. Transducer D-Connector Pin Assignments
Caution!
Do not supply +DC power
at the D-connector while
using a power supply at the
power jack. Both supplies
may be damaged.
Caution!
Operating a 12 VDC trans-
ducer at 24 VDC will cause
equipment damage.

Series 820 Instruction Manual Chapter 2 Installation
IM-82-C 2-5
Standard 0-5 VDC Output Signal Wiring
The standard 0-5 VDC output signal flows from Pin 3 (0-5 VDC
Out) through the load (1K Ohm minimum) to Pin 7 (Power Com-
mon). The figure below is a typical example of input power and
output signal connections.
Figure 2-3. Standard 0-5 VDC Output Signal Wiring
Optional 4-20 mA Output Signal Wiring
The optional 4-20 mA output signal flows from Pin 9 (4-20 mA Out)
through the load (50 to 500 Ohms maximum) to Pin 7 (Power Com-
mon). The figure below is a typical example of input power and out-
put signal connections. (Multiple transducer current loop output con-
nections are given on the next page.)
Figure 2-4. Single Transducer Current Loop Connection

Chapter 2 Installation Series 820 Instruction Manual
2-6 IM-82-C
Figure 2-5. Multiple Transducer Current Loop Connections
Remote Display Installation
Mount the remote display at a convenient location within reach of the
supplied interface cable. The maximum cable length is 100 feet (30 m).
Figure 2-6. Mounting the Remote Display

Series 820 Instruction Manual Chapter 3 Operation
IM-82-C 3-1
Chapter 3 Operation
The output signal of the transducer is either 0-5 VDC (standard) or
4-20 mA (optional). The output signal is linear and proportional to
the gas mass flow rate. For example, for a 0-5 VDC output signal,
5.00 VDC is the output signal for the full scale listed on the trans-
ducer’s nameplate, 2.50 VDC is for one-half of full scale, and 0.00
VDC is for zero flow. For a 4-20 mA output signal, 20.00 mA is the
output signal for the full scale, 12.00 mA is for one-half of full
scale, and 4.00 mA is for zero flow.
Transducer Operation
When the transducer is installed and the system has undergone a
complete leak check:
1. Apply power. The output signal will be at a high level for the
first 10 to 20 seconds while the sensor warms up to its normal
operating temperature range. Assuming zero flow, the output
signal will then drop to zero (or 4 mA, depending on output con-
figuration). Allow at least thirty minutes of warm-up time.
2. For first-time start ups, perform an initial zero output check as
described on page 3-3. After checking the initial zero setting, the
transducer is ready to monitor the gas mass flow rate.
Transducer Accuracy
The standard accuracy of Top-Trak is ±1.5% of full scale. The
±1.5% of full scale accuracy means that the 0-5 VDC output signal
is accurate to within ±0.1 VDC. The 4-20 mA output is accurate to
within ±0.4 mA.
For example, the output signal for zero flow can be as much as
+0.1 VDC or +0.4 mA. If the transducer has an output signal at
zero flow, as long as it is within either of these two ranges, it does
not mean it is malfunctioning.
For transducers with a digital display, the accuracy is simply 1.5
times the full scale flow rate stated on the nameplate. For example,
if the full scale is 10 slpm, the digital display will be accurate to
±0.2 slpm. The reading at zero flow may be as much as +0.2 slpm
and still be within the stated accuracy specification.

Chapter 3 Operation Series 820 Instruction Manual
3-2 IM-82-C
Referencing the Transducer to Non-Standard Conditions
The gas flow rate output of your transducer is referenced to “standard”
conditions of 21°C (70°F) and 760 mm of mercury (1 atmosphere)
unless otherwise specified on the certificate of calibration. Check the
stated reference conditions of your transducer. If you are comparing
your transducer’s output with another type of flow meter, different
reference conditions could cause a discrepancy between the flow
readings.
For example, the output reading of a Top-Trak will be approximately
7% lower when referenced to 0°C rather than 21°C. To find the flow
rate referenced to other standard conditions or the actual temperature
and pressure conditions in the pipe where your transducer is located,
see Appendix A.
Transducer Over-Ranging
If the flow rate exceeds the full scale value listed on the transducer
nameplate, the output signal and digital display (if so equipped) will
read a higher value. The transducer is not calibrated for over-ranged
flows and will probably be both non-linear and inaccurate. Over-
range conditions are indicated by the display and/or output signal
going to a level above the full scale range. When the over-range
condition is removed, it may take several seconds for the transducer
to recover and resume normal operation.
If the supply voltage is only 12 VDC, the over-ranged reading may
exceed the full scale value by 10% maximum. If the supply voltage
is higher, as with the 24 VDC option, then the output can exceed the
full scale by as much as 50%, or more. Digital displays cannot ex-
ceed 3-1/2 digits (1999). If the flow rate exceeds 1999, the right-
most digits will blank and only the left-hand “1” will appear on the
display.

Series 820 Instruction Manual Chapter 3 Operation
IM-82-C 3-3
Zero and Span Adjustments
The zero and span potentiometers are
accessed through the ports marked on
the side of the transducer. Normally,
span adjustments are not made unless
you are calibrating the transducer. The
span adjustment should not be used
unless you have a known, precise non-
zero flow rate that you wish to match.
Before making any zero adjustments,
confirm that the system has reached its
normal operating temperature and pres-
sure and the transducer is mounted in
its final position.
For transducers without the digital display:
1. Power the transducer and allow at least 30 minutes of warm up
time before attempting any adjustments. Set gas flow to zero.
Confirm that no flow exists.
2. Connect a digital multimeter to Pin 3 (0-5 Out) or, Pin 9 (4-20 Out)
and Pin 7 (Power Common). Check the reading. If it does not indi-
cate 0± .05 VDC, (or 4.0± .016mA) adjust the zero potentiometer.
Since the output does not indicate negative numbers, it is neces-
sary to adjust down from a slightly positive reading. Begin by
slowly rotating the zero pot clockwise until a positive reading is
indicated. To complete the zero adjustment, slowly turn the pot
counterclockwise until zero is achieved.
For transducers with the digital display:
1. Power the transducer and allow at least 30 minutes of warm up
time before attempting any adjustments. Set gas flow to zero.
Confirm that no flow exists.
2. Observe the reading on the digital display. If the reading is
greater than 1.5% of full scale, adjust the zero potentiometer.

Chapter 3 Operation Series 820 Instruction Manual
3-4 IM-82-C