Page 1
Series 780S Instruction Manual Table of Contents
Sierra 780S Series Flat-Trak
Mass Flow Meter
Instruction Manual
Part Number IM-78S
07/99 Revision B
™
Sierra Instruments b.v. Bolstoen 30A 1046 AV Amsterdam The Netherlands
IM-78S-B 0-1
5 Harris Court, Building L Monterey, CA 93940
(831) 373-0200 (800) 866-0200 Fax (831) 373-4402
http://www.sierrainstruments.com
+31(0)20-6145810 Fax +31(0)20-6145815
Page 2
Table of Contents Series 780S Instruction Manual
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 for oxygen
gas. You are responsible for determining if this mass flow meter is appropriate for
your oxygen application. You are responsible for cleaning the mass flow meter to
the degree required for your oxygen flow application.
© COPYRIGHT SIERRA INSTRUMENTS 1998
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
Flat-Trak™, Steel-Trak™ and Smart Interface™ software 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.
0-2 IM-78S-B
Page 3
Series 780S Instruction Manual Table of Contents
Table of Contents
Chapter 1 Introduction
Series 780S Flat-Trak Mass Flow Meters ..........................1-1
Using this Manual.................................................1-1
Note and Safety Information.....................................1-2
Receipt of System Components .................................1-2
Technical Assistance..............................................1-2
The Series 780S Flow Sensing Principle...........................1-3
Smart Electronics Features............................................1-4
Enclosure Options .....................................................1-5
Smart Interface™ Software............................................1-5
Chapter 2 Installation and Wiring
Installation Overview..................................................2-1
Unobstructed Flow Requirements...............................2-2
Installing the Flow Meter .............................................2-2
Changing Display Orientation....................................2-3
Wiring Connections ...................................................2-4
Input Power Wiring...............................................2-5
Output Signal Wiring .............................................2-7
Alarm Output Wiring.............................................2-10
Remote Sensor Probe Wiring...................................2-11
Range Selection Wiring..........................................2-13
Chapter 3 Operating Instructions
Flow Meter Start Up...................................................3-1
Using the Smart Electronics Basic Features........................3-2
Hazardous-Area Enclosure Optional LCD Display............3-2
LCD Display Programming Menu...............................3-3
Single-Digit LED Programming Menu..........................3-4
Entering Alarm Parameters.......................................3-5
K-Factor Adjustment..............................................3-6
User Full Scale Adjustment......................................3-7
Time Response Delay Adjustment...............................3-8
Totalizer Reset.....................................................3-9
Using the Smart Electronics Advanced Features..................3-11
Voltage Zero Adjustment........................................3-11
Voltage Span Adjustment........................................3-11
Current Zero Adjustment........................................3-12
Current Span Adjustment........................................3-12
Instrument Validation.................................................3-13
Electronics Validation Procedure...............................3-14
Sensor Validation Procedure....................................3-15
IM-78S-B 0-3
Page 4
Table of Contents Series 780S Instruction Manual
Chapter 4 Troubleshooting and Repair
Troubleshooting the Flow Meter.....................................4-1
Returning Equipment to the Factory.................................4-3
Appendix A Product Specifications
List of Figures
1-1. Series 780S Flow Sensing Principle .......................1-3
2-1. Flow Meter Orientation.......................................2-2
2-2. Wiring Access NEMA 4X Enclosures .....................2-4
2-3. Wiring Access Hazardous-Area Enclosures...............2-4
2-4. AC Input Power Connections...............................2-5
2-5. Ferrite Clamp Installation....................................2-5
2-6. DC Input Power Connections (NEMA 4X) ...............2-6
2-7. DC Input Power Connections (Hazardous-Area).........2-6
2-8. DC Output Signal Connections (NEMA 4X)..............2-7
2-9. DC Output Signal Connections (Hazardous-Area)........2-7
2-10. Load Resistance Versus Input Voltage.....................2-8
2-11. Isolated 4-20 mA Loop (NEMA 4X).......................2-9
2-12. Non-isolated 4-20 mA Loop (NEMA 4X).................2-9
2-13. Isolated 4-20 mA Loop (Hazardous-Area).................2-9
2-14. Non-isolated 4-20 mA Loop (Hazardous-Area)...........2-9
2-15. Isolated Alarm Connections (NEMA 4X).................2-10
2-16. Non-Isolated Alarm Connections (NEMA 4X) ..........2-10
2-17. Isolated Alarm Connections (Hazardous-Area) ..........2-11
2-18. Non-isolated Alarm Connections (Hazardous-Area) ....2-11
2-19. Remote Electronics to Sensor (NEMA 4X)...............2-12
2-20. J Box to Remote Enclosure (NEMA 4X).................2-12
2-21. Remote Electronics to Sensor (Hazardous-Area) ........2-12
2-22. J Box to Remote Enclosure (Hazardous-Area)...........2-13
2-23. Range Selection Wiring (NEMA 4X) .....................2-13
2-24. Range Selection Wiring (Hazardous-Area)...............2-13
3-1. Smart Electronics Device Locations ........................3-1
3-2. Magnetic Switch Operation..................................3-2
3-3. Electronics Validation Component Locations.............3-13
3-4. Sensor Validation Component Locations .................3-15
List of Tables
2-1. Pipe Length Requirements for Installation.................2-2
3-1. Electronics Validation Results..............................3-15
3-2. Sensor Validation Results...................................3-16
0-4 IM-78S-B
Page 5
Series 780S Instruction Manual Table of Contents
Warnings and Cautions
Warning! Agency approval for hazardous location installations varies between flow
meter models. Consult the flow meter nameplate for specific flow meter approvals before any hazardous location installation.
Warning! All wiring procedures must be performed with the power off.
Warning! To avoid potential electric shock, follow National Electric Code safety practices
or your local code when wiring this unit to a power source and to peripheral devices. Failure to do so could result in injury or death. All AC power connections must be in accordance with published CE directives.
Warning! Do not power the flow meter with the sensor jumper wires disconnected. This
could cause over-heating of the sensors and/or damage to the electronics.
Warning! Before attempting any flow meter repair, verify that the line is de-pressurized.
Warning! Always remove main power before disassembling any part of the mass flow meter.
Caution! Changing the length of cables or interchanging sensors or sensor wiring
will affect the accuracy of the flow meter. You cannot add or subtract wire length without returning the meter to the factory for re-calibration.
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 meter.
Caution! The AC wire insulation temperature rating must meet or exceed 71°C (158°F).
Caution! Before making adjustments to the Smart Electronics device, verify the flow meter
is not actively monitoring or reporting to any master control system. Adjustments to the
electronics will cause direct changes to flow control settings.
Caution! Printed circuit boards are sensitive to electrostatic discharge. To avoid
damaging 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
IM-78S-B 0-5
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Table of Contents Series 780S Instruction Manual
0-6 IM-78S-B
Page 7
Series 780S Instruction Manual Chapter 1 Introduction
Chapter 1 Introduction
Series 780S Flat-Trak™ Mass Flow Meters
Sierra’s Series 780S Flat-Trak Mass Flow Meter provides a reliable
solution for monitoring gas mass flow rate. Low-flow sensitivity,
fast response and outstanding rangeability have made this model the
instrument of choice for many critical gas flow applications. The
Series 780S meter solves the problems associated with monitoring
flow in installations where long runs of straight pipe are not available. The instrument’s built-in flow conditioner creates a uniform
velocity profile by means of two stainless-steel perforated plates
welded into the body between the sensor and the inlet connection.
With flow conditioning, upstream piping requirements are reduced
to less than three diameters after most common flow disturbances.
The flow meter’s versatile microprocessor-based transmitter integrates
the functions of flow-range adjustment, meter validation and diagnostics in a probe-mounted or remotely mounted housing. Mass flow rate
and totalized flow, as well as other configuration variables are displayed on the meter’s optional LCD display. The meter provides an
optical/galvanic isolated flow output, two alarm outputs and one contact input for range or gas selection. The programmable transmitter is
easily configured via RS-232 and Sierra’s Smart Interface™ software
or through three push buttons built into the device.
The Series 780S Mass Flow Meter’s simple installation combines
with an easy-to-use interface that provides quick set up, long term
reliability and accurate mass flow measurement over a wide range of
flows and conditions.
Using This Manual
This manual provides the information you need to install and operate
the Series 780S Mass Flow Meter. The four chapters of this manual
cover the following areas:
• Chapter 1 includes the introduction and product description
• Chapter 2 provides installation and wiring instructions
• Chapter 3 describes system operation and programming
• Chapter 4 covers troubleshooting and repair
The product specifications are found in Appendix A.
IM-78S-B 1-1
Page 8
Chapter 1 Introduction Series 780S Instruction Manual
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.
Receipt of System Components
When receiving a Sierra mass flow meter, 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. 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 factory
without first contacting Sierra Customer Service.
Technical Assistance
If you encounter a problem with your flow meter, review the configuration information for each step of the installation, operation and
setup procedures. Verify that your settings and adjustments are consistent with factory recommendations. Refer to Chapter 4, Troubleshooting, 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 (831) 373-0200 between 8:00 a.m. and 5:00 p.m. PST.
In Europe contact Sierra Instruments bv at +31 20 6145810. When
contacting Technical Support, make sure to include this information:
• the flow range, serial number and Sierra order
• the software version (visible at start up)
• the problem you are encountering and any corrective
• application information (gas, pressure, temperature
number (all marked on the meter nameplate)
action taken
and piping configuration)
1-2 IM-78S-B
Page 9
Series 780S Instruction Manual Chapter 1 Introduction
The Series 780S Flow Sensing Principle
Sierra’s unique Steel-Trak™ sensor probe is responsible for the unsurpassed accuracy, ruggedness and reliability of Sierra industrial
flow meters. The immersible Steel-Trak sensor consists of two
sensing elements–a velocity sensor and a temperature sensor that
automatically corrects for changes in gas temperature.
When power is applied to the flow meter, the transducer electronics
heats the velocity sensor to a constant temperature differential above
the gas temperature and measures the cooling effect of the gas flow.
The electrical power required to maintain a constant temperature differential is directly proportional to the gas mass flow rate.
Both sensors are reference-grade platinum resistance temperature
detectors (RTDs). The platinum RTD wire is wound on a rugged ceramic mandrel for strength and stability. Steel-Trak sensors are clad
in a rugged, sealed 316 stainless steel encasement.
IM-78S-B 1-3
Figure 1-1. Series 780S Flow Sensing Principle
Page 10
Chapter 1 Introduction Series 780S Instruction Manual
Smart Electronics Features
Instrument Validation
Two simple tests offer full “field-validation” of your Smart mass
flow meter. The first test checks the system electronics, linearization
and microprocessor functionality and is performed by injecting a
known input value and confirming that the flow meter outputs the
expected value. The second test verifies that the instrument’s primary sensing elements have not drifted or shifted from their original
calibration and is accomplished by measuring the resistance of the
velocity and temperature sensors and comparing the results to the
NIST-traceable calibration data provided with the flow meter. Together, these tests confirm that your meter is working correctly and
the calibration variables did not drift, shift or change values.
Dual Range or Dual Gas Calibration (Optional)
Select one of two factory calibrated flow ranges using a simple external customer-supplied single contact closure.
User Full Scale Flow Rate
Field-configure from 50% to 100% of the factory full scale setting
(factory full scale is normally set to 125% of the user-specified maximum flow rate). This adjustment can be made for each flow range.
Alarms
Program high and low or window alarm limits independently for
each flow range. The solid state contacts are optically isolated.
K-Factor Correction
Change the calibration correction factor to compensate for flow profile disturbances or specific application conditions. The K-factor is a
multiplication factor applied to the linearized flow signal. You may
set the K-factor individually for each flow range.
Dual Output Signals
The flow meter offers two separate linear output signals proportional to flow, 0-5 VDC (0-10 VDC optional) and 4-20 mA. The
4-20 mA output can be field-configured as an active loop powered
by the flow meter or an optically isolated passive loop requiring an
external power supply.
1-4 IM-78S-B
Page 11
Series 780S Instruction Manual Chapter 1 Introduction
Totalizer
With the optional LCD display, actual mass flow appears on line 1
and the totalized flow on line 2 both in the user-specified engineering units. The totalizer counts only the selected range and when
ranges are switched, the value of the non-selected range is stored in
memory. You may reset the totalizer using the membrane buttons or
by using a hand-held magnet.
Zero and Span Outputs
Validate and adjust the settings to ensure output circuits are correct.
Time Response Delay
Select from a low response for faster tracking to a high response
for a smoother output.
Enclosure Options
Flow meter electronics are available mounted directly to the flow
body, or remotely mounted up to 200 feet away. The electronics
housing may be used indoors or out, including wet environments.
Display options include a 2 x 12 character LCD display of mass flow
rate including totalized mass, or a single-digit LED located on the device printed circuit board. Local operation and reconfiguration is accomplished using the three push buttons operated via finger touch.
Smart electronics include nonvolatile memory that stores all configuration information. The memory allows the flow meter to function
immediately upon power up, or after an interruption in power.
Smart Interface™ Software
Sierra’s Smart Interface Windows™-based software is available for
connecting your PC directly to the mass flow meter. An RS-232 serial cable along with floppy disks containing the program and system files are available from the factory. See the Smart Interface User
Guide included with the software package for operating instructions.
(Order code for this package is 780-SIP.)
IM-78S-B 1-5
Page 12
Chapter 1 Introduction Series 780S Instruction Manual
1-6 IM-78S-B
Page 13
Series 780S Instruction Manual Chapter 2 Installation
Warning!
Agency approval for hazardous
location installations varies
between flow meter models.
Consult the flow meter name-
plate for specific flow meter
approvals before any hazard-
ous location installation.
Chapter 2 Installation
Installation Overview
The Series 780S Flat-Trak™ is available with ANSI or DIN flanges,
NPT or butt-weld connections. For ease of installation, the meter is
pre-assembled with the sensor probe installed in the flow body.
When selecting an installation site, make sure that:
1. Line pressure and temperature will not exceed the flow meter
rating. Temperature should not vary more than 200°F (100°C)
around the calibration temperature. Line pressure should not
vary more than 50 psi (3.4 bar) around the calibrated pressure.
2. The location meets the required minimum number of pipe
diameters upstream and downstream of the sensor head (see
Table 2-1).
3. Safe and convenient access with adequate clearance. Also, verify
the meter is located where the gas is clean and dry and the meter
is calibrated for the gas to be measured.
4. When using a CSA, FM or EEx approved flow meter, verify that
the cable entry into the instrument meets the specific standard required for that approval.
5. For remote installations, verify the supplied cable length is suffi-
cient to connect the flow meter sensor to the remote electronics.
(Do not extend or shorten the supplied cable between the probe
and the electronics.)
IM-78S-B 2-1
Also, before installation check your flow system for anomalies
such as:
• leaks
• valves or restrictions in the flow path that could create dis-
turbances in the flow profile that might cause unexpected
flow rate indications
• heaters that might cause rapid excursions in the measured
temperature
Page 14
Chapter 2 Installation Series 780S Instruction Manual
Unobstructed Flow Requirements
Select an installation site that will minimize possible distortion in the
flow profile. Valves, elbows, control valves and other piping components may cause flow disturbances. Check your specific piping condition against the examples shown below. To achieve accurate and repeatable performance, install the flow meter using the recommended
number of straight run pipe diameters upstream of the sensor.
Piping Condition Upstream
Single 90° elbow or T-piece 1 D
Reduction (4:1) 3 D
Expansion 3 D
After a control valve 3 D
Two 90° elbows (in same plane) 3 D
Two 90° elbows (different planes) 5 D
(1) Number of diameters (D) of straight pipe required between upstream disturbance and the flow meter sensor.
Table 2-1. Pipe Length Requirements for Installation
Installing the Flow Meter
Enclosure
adjustable to any
viewing position
FLOW
SIERRA
(1)
Requirements
Flow direction indicator
should point downstream
in the direction of flow
Figure 2-1. Flow Meter Orientation (Flange Connection Shown)
When positioning the flow meter, refer to the flow direction indicator
attached to the probe. For proper operation, install the meter with the
flow direction indicator pointing downstream in the direction of flow.
Installing the meter opposite this direction may result in inaccurate
flow measurement.
2-2 IM-78S-B
Page 15
Series 780S Instruction Manual Chapter 2 Installation
To install the flow meter:
1. Turn off the flow of process gas. Verify that the line is not pres-
Caution!
When using toxic or cor-
rosive gases, purge the
line with inert gas for a
minimum of four hours at
full gas flow before in-
stalling the flow meter.
surized. Confirm that the installation site meets the minimum up-
stream pipe diameter requirements shown in Table 2-1.
2. Prepare the fluid connection fittings or flanges in the pipeline.
(Fitting components should be blown clean with filtered gas be-
fore use.) Mount in a vertical position. For horizontal pipelines
having a process gas temperature above 300° F (130°C), mount the
flow meter at a 90-degree angle to avoid overheating the electron-
ics enclosure.
3. Seat the flow meter level and square on the mating fluid connec-
tions with a gasket in place for each side for flange types. (Make
sure both gaskets are smooth and even with no gasket material
protruding into the flow profile; obstructions in the pipeline could
cause inaccurate flow measurement.) Make sure that the flow di-
rection indicator is pointing downstream in the direction of flow.
4. Secure the fluid connections as specified in the technical guidelines
furnished by the fitting or flange manufacturer.
5. If needed, adjust the optional display to the desired orientation,
as follows.
Changing Display Orientation (Hazardous-Area Enclosures Only)
Depending on installation requirements, you may need to change the
position of the optional display. To rotate the display board:
1. Use a 1/16-inch hex key to loosen the set screw securing the
larger end of the enclosure. Turn cover counterclockwise and
remove.
2. Remove 4 screws and standoffs from the display. Release the
latch securing the display ribbon cable connector from the dis-
play board.
3. Rotate the display board to the desired position. Re-connect the
ribbon cable to the display board.
4. Replace the 4 screws and standoffs. Replace the enclosure
cover. Tighten set screw.
IM-78S-B 2-3
Page 16
Chapter 2 Installation Series 780S Instruction Manual
Wiring Connections
For NEMA 4X enclosures, use TB2 for power and signal connections, TB1 is for sensor connections. (The terminal designations are
labeled inside the enclosure cover.)
Warning!
To avoid potential electric
shock, follow National Electric Code safety practices or
your local code when wiring
this unit to a power source
and to peripheral devices.
Failure to do so could result
in injury or death. All AC
power connections must be
in accordance with pub-
lished CE directives.
To access components:
1. Loosen 4 screws.
2. Remove cover.
Figure 2-2. Wiring Access NEMA 4X Enclosures
Wiring connections
inside cover
NEMA 4X enclosure
terminal blocks
TB2
1
2
3
4
5
6
7
8
9
10
12
14
16
TB1
11
13
15
6
5
4
3
2
1
For Hazardous-Area enclosures, use the terminal blocks located inside the smaller end of the flow meter enclosure for all wiring connections. (The terminal designations are labeled inside the enclosure
cover.) Make sure to observe all CE compliance requirements for
AC wiring connections given on the next page.
Set screw
Wiring
connections
To access components:
1. Use 1/16 inch hex key to loosen set screw.
2. Turn cover counterclockwise to remove.
Figure 2-3. Wiring Access Hazardous-Area Enclosures
Hazardous-Area enclosure
terminal blocks
1
20
2
19
3
18
4
17
5
16
6
15
7
14
8
13
9
12
10
11
2-4 IM-78S-B
Page 17
Series 780S Instruction Manual Chapter 2 Installation
Input Power Wiring
AC Power Wiring
The AC power wire size must be 26 to 16 AWG with the wire
Warning!
All wiring procedures must
be performed with the power
Off.
Caution!
The AC wire insulation tem-
perature rating must meet or
exceed 71°C (158°F).
stripped 1/4 inch (6 mm). Connect 100 to 240 VAC (300 mA load,
maximum) to the Neutral and Line terminals on the small, twoposition terminal block. Connect the ground wire to the safety ground
lug. Torque all connections to 4.43 to 5.31 in-lbs (0.5 to 0.6 Nm).
For all installations not using solid metal conduit, the ferrite clamp
must be installed just above the input power wire entry into the enclosure (Figure 2-5). All EEx installations must use an approved
EEx fitting at both cable entries into the enclosure. If conduit seals
are used, they must be installed with 18 inches of the enclosure.
The Hazardous-Area enclosure has two separate conduit entries to
maintain separation between AC input power and output signal wiring. To eliminate the possibility of noise interference use a separate
cable entry for the AC power and signal lines.
Hazardous-Area Enclosures
AC Power (Line)AC Power (Neutral)
1
20
2
19
3
18
4
17
5
16
6
15
7
14
8
13
9
12
10
11
Figure 2-4. AC Input Power Connections
Enclosure
safety
ground lug
IM-78S-B 2-5
Figure 2-5. Ferrite Clamp Installation
Page 18
Chapter 2 Installation Series 780S Instruction Manual
DC Power Wiring
The DC power wire size must be 26 to 16 AWG with the wire
stripped 1/4 inch (6 mm). Connect 18 to 30 VDC (625 mA load,
Warning!
All wiring procedures
must be performed with
the power Off.
maximum) to the terminals marked PWR+ and PWR– on the terminal
block. Torque all connections to 4.43 to 5.31 in-lbs (0.5 to 0.6 Nm).
All EEx installations must use an approved EEx fitting at both cable
entries into the enclosure. If conduit seals are used, they must be installed within 18 inches of the enclosure.
NEMA 4X Enclosures
DC Power (+)
1
2
DC Power (–)
15
16
Figure 2-6. DC Input Power Connections
Hazardous-Area Enclosures
DC Power (+)
DC Power (–)
1
20
2
19
3
18
4
17
5
16
6
15
7
14
8
13
9
12
10
11
Figure 2-7. DC Input Power Connections
2-6 IM-78S-B
Page 19
Series 780S Instruction Manual Chapter 2 Installation
Output Signal Wiring
Output signal cable should be completely screened with a 100%
shield. You must use metal cable glands that provide cable screen
clamping. The cable screen should be connected to the gland and
shielded at both ends over 360 degrees. The shield should be terminated to an earth ground.
Flow meters are equipped with either a calibrated 0-5 VDC (0-10
VDC optional) or a calibrated 4-20 mA output signal. This linear
output signal represents 0-100% of the flow meter’s user full
scale.
DC Output Wiring
The 0-5 VDC (0-10 VDC optional) signal can drive a minimum load
of 1000 Ohms. Note: the optional 0-10 VDC output signal is not
available for power sources below 15 VDC.
For 0-5 VDC or 0-10 VDC connections, connect to the terminals
marked Vout (+) and Vout (–) as shown below.
NEMA 4X Enclosures
1
2
0-5 V out (+)
0-5 V out (–)
15
16
Figure 2-8. DC Output Signal Connections
Hazardous-Area Enclosures
1
20
2
0-5 V out (+)
0-5 V out (–)
19
3
18
4
17
5
16
6
15
7
14
8
13
9
12
10
11
IM-78S-B 2-7
Figure 2-9. DC Output Signal Connections
Page 20
Chapter 2 Installation Series 780S Instruction Manual
4-20 mA Output Wiring
The 4-20 mA current loop output can be self-powered (non-isolated)
or externally powered (isolated). To use the 4-20 mA isolated output,
an external 12 to 36 VDC power supply is required. The maximum
loop resistance (load) for both types of current loop outputs are dependent upon the supply voltage and are given in Figure 2-10.
R
is the total resistance in the loop, including the wiring resis-
load
tance. To calculate R
, the maximum R
max
for the loop, use the
load
maximum loop current, 20 mA. The voltage drop in the loop due to
resistance is 20 mA times R
and this drop is subtracted from the
load
input voltage. Thus:
R
the maximum load resistance = 50 * (V
max
supply
– 7.5V)
To use an external power supply for an isolated 4-20 mA output, connect as shown in Figure 2-11 or Figure 2-13. For an internally powered, non-isolated 4-20 mA output, connect as shown in Figure 2-12
or Figure 2-14.
Figure 2-10. Load Resistance Versus Input Voltage
V
supply
(Volts) (Ohms)
11 (min) 175
12 225
15 375
18 525
24 825
30 1,125
36 (max) 1,425
R
max
2-8 IM-78S-B
Page 21
Series 780S Instruction Manual Chapter 2 Installation
NEMA 4X Enclosures
1
2
R load
Current
4-20 out (+)
4-20 out (–)
– +
12 VDC
to
36 VDC
15
16
Figure 2-11. Isolated 4-20 mA Current Loop Connections
NEMA 4X Enclosures
1
2
AUX PWR OUT
4-20 out (+)
15
16
R load
Jumper
Current
V out (–)
(Common)
Figure 2-12. Non-Isolated 4-20 mA Current Loop Connections
Hazardous-Area Enclosures
1
20
2
19
3
18
4
17
5
16
6
15
7
14
8
13
9
12
10
11
+
12 VDC
to
36 VDC
–
4-20 out (+)
4-20 out (–)
R load
Current
Figure 2-13. Isolated 4-20 mA Current Loop Connections
IM-78S-B 2-9
Hazardous-Area Enclosures
1
20
2
19
3
18
4
17
5
16
6
15
7
8
9
10
Com
14
13
12
11
Use either
Pin 4 or 14,
NOT BOTH
Current
Jumper
4-20 out (–)
R load
Figure 2-14. Non-Isolated 4-20 mA Current Loop Connections
Page 22
Chapter 2 Installation Series 780S Instruction Manual
Alarm Output Wiring
Two alarm outputs (Low Alarm and High Alarm) are included on the
flow meter terminal block. The alarm outputs use optical relays that are
normally-open single-pole relays with one common connection.
There are two connection options for alarm outputs–the first with a separate power supply (isolated) and the second using the flow meter power
supply (non-isolated). Use the first option with a separate power supply
if a specific voltage is needed for the alarm output. Use the second (nonisolated) configuration if the voltage at the flow meter’s power supply is
an acceptable driver voltage for the load connected. (Take into account
that the current used by your alarm loads have to come from the flow
meter’s power supply.) In either case, the voltage of the alarm output is
the same as the voltage supplied to the circuit.
To use an external power supply for an isolated alarm output, connect as shown in Figure 2-15 or Figure 2-17. To use the internally
powered, non-isolated alarm output connect as shown in Figure 2-16
or Figure 2-18. For a window alarm connect both outputs together.
NEMA 4X Enclosures
AC or DC
power supply
Load Load
ALRM COM
HI ALARM (–)
LO ALARM (–)
1
2
15
16
Figure 2-15. Isolated Alarm Output Connections
NEMA 4X Enclosures
1
LoadLoad
ALRM COM
LO ALARM (–)
COMMON
2
AUX DC PWR OUT
HI ALARM (–)
15
16
Figure 2-16. Non-Isolated Alarm Connections
2-10 IM-78S-B
Page 23
Series 780S Instruction Manual Chapter 2 Installation
Hazardous-Area Enclosures
1
20
2
19
3
18
4
17
5
16
6
15
7
14
8
13
9
12
10
11
Load Load
AC or DC
power supply
HI ALARM (–)
LO ALARM (–)
ALRM COM
Figure 2-17. Isolated Alarm Output Connections
Hazardous-Area Enclosures
1
20
2
19
3
DC POWER OUT
Load Load
HI ALARM (–)
LO ALARM (–)
18
4
17
5
16
6
15
7
14
8
13
9
12
10
11
ALRM COM
Caution!
Changing the length of ca-
bles or interchanging sen-
sors or sensor wiring will af-
fect the accuracy of the flow
meter. You cannot add or
subtract wire length without
returning the meter to the fac-
tory for recalibration.
Figure 2-18. Non-Isolated Alarm Connections
Remote Sensor Probe Wiring
When connecting the sensor probe to a remotely mounted flow
meter enclosure, use only factory supplied cables. The electronics,
sensors and interconnecting cables supplied by Sierra Instruments
are calibrated as a complete precision mass flow circuit.
To connect the sensor probe to a remotely mounted electronics
enclosure, see Figure 2-19 or Figure 2-21. To make wiring
connections from a sensor probe junction box to a remotely
mounted enclosure, see Figure 2-20 or Figure 2-22.
IM-78S-B 2-11
Page 24
Chapter 2 Installation Series 780S Instruction Manual
NEMA 4X Enclosures
Remote
enclosure
Sensor
probe
RED
GREEN
Note: Sensor wire color may vary - see label in cover
WHITE
BLACK
Temperature
ORANGE
sensor
Velocity
sensor
Figure 2-19. Remote Electronics Enclosure to Sensor Connections
Figure 2-20. Sensor Junction Box to Remote Enclosure Connections
Hazardous-Area Enclosures
1
20
2
19
3
18
4
Remote
enclosure
17
5
16
6
15
7
14
8
13
9
12
10
11
GREEN
ORANGE
RED
WHITE
BLACK
Note: Sensor wire color may vary - see label in cover
Sensor
probe
Figure 2-21. Remote Electronics to Sensor Connections
2-12 IM-78S-B
Page 25
Series 780S Instruction Manual Chapter 2 Installation
Figure 2-22. Sensor Junction Box to Remote Enclosure Connections
Range Selection Wiring
To access range selection, connect two wires on the terminal strip as
shown below. When the switch is closed the device changes to
Range 2. Opening the switch returns the device to Range 1.
IM-78S-B 2-13
Figure 2-23. Range Selection Wiring
Hazardous-Area Enclosures
1
20
2
19
3
18
4
17
5
16
15
14
13
12
11
RANGE SELECT
COMON
6
7
8
9
10
Figure 2-24. Range Selection Wiring
Range 1
Range 2
Page 26
Chapter 2 Installation Series 780S Instruction Manual
2-14 IM-78S-B
Page 27
Series 780S Instruction Manual Chapter 3 Operation
Chapter 3 Operation
This chapter covers flow meter operation, programming and instrument validation procedures. All instructions include directions for
using either the optional LCD display or the internal Smart electronics device for programming. If your meter is not equipped with the
optional display, you will need a good quality digital voltmeter or
multimeter for programming and validation procedures.
Flow Meter Start Up
When applying power to a flow meter equipped with the optional
LCD display you will see the product name, the software version,
unit serial number, the range number, the user full scale (UFS), the
current flow rate and the totalized flow. Any active alarm will flash
on the screen every few seconds.
When applying power to a flow meter without the display, the Smart
electronics on-board single-digit LED flashes the revision number of
the software in a series of 3 digits followed by the range number.
The range number continues to flash every three seconds thereafter.
Record Factory-Set Parameters
You may view parameters using the optional LCD front panel display or by selecting functions on the single-digit LED and viewing
the meter’s 0-5 VDC output with a digital voltmeter (DVM).
For meters with the LCD display, use a hand-held magnet or the device buttons to select the FUNCTION key. When FUNCTION is
selected, the display prompts for a password. Select FUNCTION
again to skip the password to view and record the factory settings.
To make changes, at the password prompt use the UP arrow until
the number 11 is displayed. Select FUNCTION again to continue.
For flow meters without the display, remove the enclosure cover to
access the Smart electronics device. Connect the DVM as described on
the following pages and record the factory-set parameters.
Smart Electronics Device
Single
digit LED
Inside cover Inside cover
Function
Up
Down
Figure 3-1. Smart Electronics Device Locations
IM-78S-B 3-1
Page 28
Chapter 3 Operation Series 780S Instruction Manual
Using the Smart Electronics Basic Features
This section covers the basic features of the Smart electronics and includes instructions on:
Caution!
Before making any ad-
justment to the Smart
electronics device, verify
the flow meter is not ac-
tively monitoring or report-
ing to any master control
system. Any adjustment
to the electronics will
cause direct changes to
flow control settings.
To access the meter’s advanced features of zero and span, turn to
page 3-11. Instrument validation procedures begin on page 3-13.
Note: when programming the instrument, after 12 seconds of nonactivity the meter returns to the Run Mode with any new settings immediately in effect. For units without a display, if the unit “times-out”
press the FUNCTION button only to resume adjustments.
Hazardous-Area Enclosure Optional LCD Display
For units with the optional display, you may program the meter
without opening the enclosure using the magnetic switches to enter
the desired system settings.
• entering alarm parameters
• changing the user full scale
• adjusting the K-factor
• adjusting the time response speed
• resetting the totalizer
Hazardous-Area Enclosures ONLY
Position magnet at the
midpoint of the enclosure
over the desired switch
DOWN
x
FUNCTION
To activate the magnetic switches for programming:
1. Position magnet over FUNCTION, UP or DOWN (the LED lamp indicates
switch activation).
2. Hold in place until the desired variable is displayed. Remove magnet.
NOTE: When activating magnetic switches, variables first cycle up or
down at a slow rate. When holding the magnet in position for longer
than three seconds, the cycle speed increases to a faster rate.
Figure 3-2. Magnetic Switch Operation
LED
indicator
UP
3-2 IM-78S-B
Page 29
Series 780S Instruction Manual Chapter 3 Operation
LCD Display Programming Menu
Start Up
Screens
Flow meter model
Sierra
Flow Meter
Software version
Meter serial number
Run Mode
Current flow rate
Totalized flow
Current range in use
User full scale
Current flow rate
If an alarm is active,
will flash
For units with the optional front
panel LCD display, you must
correctly enter the password to
change parameters.
To view settings, select
FUNCTION twice, skipping the
password. To change settings,
select FUNCTION. At the
password prompt, use the UP
arrow until the number 11 is
displayed. Select FUNCTION
again to continue.
Use the UP or DOWN arrows to
enter new parameters. Select
FUNCTION to continue.
After 12 seconds of non-activity,
the settings are saved and the
meter returns to the Run Mode.
Version
Serial No.
Flow
Total Flow
Range No.
UFS
Flow
Alarm
Select
FUNCTION
LCD Display
FUNCTIONS
Password
Zero Volts
Span Volts
Zero mA
Span mA
High Alarm
Low Alarm
K-Factor
User FS
Time Resp.
IM-78S-B 3-3
Total Reset?
Page 30
Chapter 3 Operation Series 780S Instruction Manual
Single-Digit LED Programming Menu
Run Mode
Software version
shown in series
of 3 digits
Range in use
Range
No.
Press
FUNCTION
FUNCTION
AssignmentsVersion
1
Voltage Zero
Voltage Span
2
Press FUNCTION to view or
change settings.
Use the UP or DOWN button
to enter new parameters.
Press FUNCTION to continue.
After 12 seconds of non-activity,
the settings are saved and the
meter returns to the Run Mode.
Current Zero
3
Current Span
4
High Alarm
5
Low Alarm
6
K-Factor
7
User Full Scale
8
Time Response
9
Delay
3-4 IM-78S-B
Page 31
Series 780S Instruction Manual Chapter 3 Operation
Entering Alarm Parameters
Use the High Alarm and Low Alarm function to set or adjust alarm
trip points. The alarms have a minimum hysteresis of 3% to avoid
Caution!
The flow meter must not be
reporting or measuring gas
flow during adjustments.
"chattering." When setting a window alarm, the alarm setpoints must
be at least twice the hysteresis value apart. We suggest at least a 10%
separation between window alarm setpoints. If you choose not to use
the high alarm for a specific alarm function, Sierra recommends that
you set the high alarm at 100% of the user full scale setting which
creates an “over-range” indicator. Your flow meter will continue to
indicate flow and generate a signal if the flow is over the maximum
range, but will not operate within the specified accuracy.
Entering Alarms using the LCD Display
Enter alarms setpoints directly in engineering units.
1. Select the desired range. Select FUNCTION, enter the password. Select FUNCTION again until High Alarm or Low Alarm
appears on the display.
2. Use UP or DOWN to enter the high or low alarm setpoint value
in engineering units.
3. Select FUNCTION to advance to the next option, or after 12
seconds of non-activity the meter returns to the Run Mode and
the new parameters are in effect.
Entering Alarms using the Single-Digit LED
When using a DVM to set alarms, the setpoint is a percentage of the
flow meter’s user full scale.
VOLTS = (ALARM PERCENT x 5.0)
If you want to alarm at 25% of user full scale, used in Step 3 below,
press the UP or DOWN button until 1.25 VDC is present on the
DVM. If you want to alarm at 75% of user full scale, press the UP
or DOWN button until 3.75 VDC is present on the DVM.
1. Set the DVM to voltage mode and connect between Vout+ and
Vout– on the flow meter terminal block.
2. Select the desired range. Press the FUNCTION button until a solid
“5” (high alarm) or solid “6” (low alarm) appears on the LED.
3. Adjust the UP or DOWN button until the DVM indicates the desired setpoint voltage as described above.
4. Press FUNCTION again to advance to the next option, or after
12 seconds of non-activity the meter returns to the Run Mode
and the new alarm parameters are in effect.
IM-78S-B 3-5
Page 32
Chapter 3 Operation Series 780S Instruction Manual
K-Factor Adjustment
Entering a K-factor adjusts the meter’s output signal without affecting the factory calibration curve. Use the K-factor calibration offset
for additional flow profile compensation (the factory includes an initial flow profile correction in the calibration curve of the unit).
Caution!
The flow meter must not be
reporting or measuring gas
flow during adjustments.
Entering a K-factor using the LCD Display
A K-factor value of 1.000 means the output value is not affected and
is the factory default setting. You may enter any number from 0.500
to 5.000.
1. Select the desired range. Select FUNCTION, enter the password.
Select FUNCTION again until K-factor appears on the display.
2. Use UP or DOWN to enter the desired K-factor value in engineering units.
3. Select FUNCTION to advance to the next option, or after 12
seconds of non-activity the meter returns to the Run Mode and
the new K-factor is in effect.
Entering K-factor using the Single-Digit LED
A K-factor value of 1.000 VDC means the output value is not affected and is the factory default setting. You may enter any value
from 0.500 to 5.000 VDC in Step 3 below. If the device indicated
output is 3.0 VDC and you know it should be 3.8 VDC then you
could “force” the output to the desired 3.8 VDC by adjusting the Kfactor to indicate 1.27 VDC (1.27 = 3.8/3.0). Use this formula to
determine the desired K-factor voltage:
VOLTS = DESIRED/ INDICATED
1. Set the DVM to voltage mode and connect between Vout+ and
Vout– on the flow meter terminal block.
2. Select the desired range. Press the FUNCTION button until a
solid “7” appears on the LED.
3. Adjust the UP or DOWN button until the DVM indicates the desired K-factor value as described above.
4. Press FUNCTION to advance to the next option, or after 12
seconds of non-activity the meter returns to the Run Mode and
the new K-factor is in effect.
3-6 IM-78S-B
Page 33
Series 780S Instruction Manual Chapter 3 Operation
User Full Scale Adjustment
The user full scale (UFS) feature adjusts the flow meter output range
anywhere within 50% to 100% of the factory full scale (FFS). This
Caution!
The flow meter must not be
reporting or measuring gas
flow during adjustments.
feature allows you to re-range the voltage or current output of the
meter to accommodate different flow rates. Note: when entering a
new user full scale setting for Range 2, it cannot be less than 10% of
the Range 1 user full scale.
Changing the User Full Scale using the LCD Display
The factory full scale is shown on the flow meter label. If you want a
UFS equal to the FFS, adjust the display to match the FFS. If you
want to use 50% of FFS, adjust the display to read 50% of the FFS.
1. Select the desired range. Select FUNCTION, enter the password.
Select FUNCTION again until User Full Scale appears on the display.
2. Use UP or DOWN to enter the desired UFS value in engineering
units.
3. Select FUNCTION to advance to the next option, or after 12
seconds of non-activity the meter returns to the Run Mode and
the new UFS is in effect.
Changing the User Full Scale using the Single-Digit LED
If the FFS is set to 11,000 sfpm and UFS is set to output 5.0 VDC,
or 100%, the flow meter will indicate 5.0 VDC when 11,000 sfpm
is present on the probe. If you want 6,000 sfpm for UFS, used in
Step 3 below, adjust the UFS to 6000/11000 or 54.55% of factory
full scale. Adjust the voltage to 2.73 VDC (2.73 = 5 x .5455). Use
this formula to determine the desired UFS voltage:
VOLTS = 5 x User Full Scale / Factory Full Scale
1. Set the DVM to voltage mode and connect between Vout+ and
Vout– on the flow meter terminal block.
2. Select the desired range. Press the FUNCTION button until a
solid “8” appears on the LED.
3. Adjust the UP or DOWN button until the DVM indicates the desired user full scale as described above.
4. Press FUNCTION to advance to the next option, or after 12
seconds of non-activity the meter returns to the Run Mode and
the new UFS is in effect.
IM-78S-B 3-7
Page 34
Chapter 3 Operation Series 780S Instruction Manual
Time Response Delay Adjustment
Changing the Time Response Delay using the LCD Display
1. Select FUNCTION, enter the password. Select FUNCTION
again until Time Response appears on the display.
2. Use UP or DOWN to adjust the time response delay from 0.10
to 7.2 seconds.
3. Select FUNCTION again to advance to the next option, or after
12 seconds of non-activity the meter returns to the Run Mode
and the new time response setting is in effect.
Changing the Time Response Delay using the Single-Digit LED
1. Set the DVM to voltage mode and connect between Vout+ and
Vout– on the flow meter terminal block. Select the desired
range. Press the FUNCTION button until a solid “9” appears on
the LED.
2. Adjust the UP or DOWN button until the DVM indicates the desired voltage (as shown in the following table).
Volts
Indicated
on DVM
0.5 0.1 1.0 0.3 1.5 0.5 2.0 0.7
2.5 1.2 3.0 1.8 3.5 2.4 4.0 3.6
4.5 4.8 5.0 7.2
3. Press FUNCTION to advance to the next option, or after 12
seconds of non-activity the meter returns to the Run Mode and
the new time response delay setting is in effect.
Time
Response
(Seconds)
Volts
Indicated
on DVM
Time
Response
(Seconds)
Volts
Indicated
on DVM
Time
Response
(Seconds)
Volts
Indicated
on DVM
Time
Response
(Seconds)
3-8 IM-78S-B
Page 35
Series 780S Instruction Manual Chapter 3 Operation
Totalizer Reset
If your device is equipped with the optional LCD display, reset the
totalizer using the magnetic switches or device buttons. If you are
unable to open the flow meter enclosure, use a magnet to reset the
totalizer as shown below.
Reset the Totalizer using the LCD Display
1. Select the desired range. Select FUNCTION, enter the password. Select FUNCTION again until Total Reset? appears on
the display.
2. Select the UP button and then the DOWN button until the display reads “Resetting Totalizer.”
Reset the Totalizer without Opening the Enclosure
1. Position a magnet above the enclosure until the display reads
“Resetting Totalizer.”
For Hazardous-Area enclosures only: To disable the magnetic reset
function of the totalizer, remove jumper (J2) from the PCB at the location shown below. (You may not disable the magnetic reset switch
on NEMA 4X enclosures.)
IM-78S-B 3-9
Page 36
Chapter 3 Operation Series 780S Instruction Manual
3-10 IM-78S-B
Page 37
Series 780S Instruction Manual Chapter 3 Operation
Using the Smart Electronics Advanced Features
Zero and span (Function 1 through 4) can be used to validate system
operation and calibrate the digital to analog signals on the Smart
Caution!
Adjusting zero or span will
affect meter calibration.
Voltage Zero Adjustment
electronics device. Additionally, these functions can compensate for
resistance in long signal cables connected to your data collection or
indicating system.
You must use a certified digital voltmeter to adjust zero and span as
the voltmeter acts as a standard. We recommend recording the current
values as shown on the LCD display or DVM before making any
changes to the zero and span settings. Note: when adjusting zero the
voltage signal will be driven to 0 VDC and when adjusting span the
voltage signal will be driven to 5 VDC (or 10 VDC).
If needed, use Zero Volts (Function 1) to adjust the 0-5 VDC output
to 0.0 VDC, or optional 0-10 VDC to 0.0 VDC.
1. Set the DVM to voltage mode and connect between Vout+ and
Vout–.
2. Select FUNCTION, enter the password (if so equipped). Select
FUNCTION again until Zero Volts appears on the LCD display
or a solid “1” appears on the LED. Adjust UP or DOWN until
the DVM indicates between 0 and .01 VDC (no less than 0.005,
the Smart electronics device cannot drive negative values).
3. After 12 seconds of non-activity, the meter returns to the Run
Mode and the new parameter is in effect.
Voltage Span Adjustment
If needed, use Span Volts (Function 2) to adjust the 0-5 VDC output
to 5.0 VDC, or optional 0-10 VDC to 10 VDC.
1. Set the DVM to voltage mode and connect between Vout+ and Vout–.
2. Select FUNCTION, enter the password (if so equipped). Select
FUNCTION again until Span Volts appears on the LCD display or
a solid “2” appears on the LED. Adjust UP or DOWN until the
DVM, indicates between 4.99 and 5.01 VDC. (For 0-10 VDC devices, the target value is 9.99 to 10.01.)
3. After 12 seconds of non-activity, the meter returns to the Run
Mode and the new parameter is in effect.
IM-78S-B 3-11
Page 38
Chapter 3 Operation Series 780S Instruction Manual
Note: when adjusting zero the current signal will be driven to 4 mA and
when adjusting span the current signal will be driven to 20 mA. We recommend recording the current values before making any changes to the current
zero or span settings.
Current Zero Adjustment
If needed, use Zero mA (Function 3) to adjust the 4-20 mA output to
4.0 mA.
Caution!
Adjusting zero or span will
affect meter calibration.
1. Disconnect the 4-20 mA (+) loop wire. Set the DVM to current
mode and connect the positive lead to the wire you just disconnected. Connect the negative lead to the 4-20 mA (–) on the flow
meter terminal block.
2. Select FUNCTION, enter the password (if so equipped). Select
FUNCTION again until Zero mA appears on the LCD display or a
solid “3” appears on the LED. Adjust UP or DOWN until the DVM
indicates between 3.95 and 4.05 mA. Set DVM back to voltage
mode when adjustment is complete.
3. After 12 seconds of non-activity, the meter returns to the Run
Mode and the new parameter is in effect.
Current Span Adjustment
If needed, use Span mA (Function 4) to adjust the 4-20 mA output
to 20.0 mA.
1. Disconnect the 4-20 mA (+) loop wire. Set the DVM to current
mode and connect the positive lead to the wire you just disconnected. Connect the negative lead to 4-20 (–) on the flow meter
terminal block.
2. Select FUNCTION, enter the password (if so equipped). Select
FUNCTION again until Span mA appears on the LCD display or a
solid “4” appears on the LED. Adjust UP or DOWN 2 until the
DVM indicates between 19.95 and 20.05 mA. Set DVM back to
voltage mode when adjustment is complete.
3. After 12 seconds of non-activity, the meter returns to the Run
Mode and the new parameter is in effect.
3-12 IM-78S-B
Page 39
Series 780S Instruction Manual Chapter 3 Operation
Instrument Validation
System electronics are verified by injecting a known input value and
confirming that the flow meter outputs the expected value. This test
confirms that the microprocessor, analog to digital and digital to
analog converters, the linearizer and the display are working properly. Sensor validation is accomplished by measuring the resistance
of the velocity and temperature sensors and comparing the results to
the NIST-traceable calibration data provided with the flow meter.
These tests confirm that your meter is working correctly and the
calibration variables did not drift, shift or change values.
To perform the instrument validation procedures you will need the
following equipment:
• certified digital multimeter with minimum 4 character resolution,
accuracy of at least ± 0.1% of range
• Calibration Certificate supplied with the flow meter
• small pot adjusting tool (screwdriver)
Before beginning the validation procedures, review Figure 3-3 and
Figure 3-4 to familiarize yourself with the component locations.
NEMA 4X Enclosures
J1
CAL
RUN
VR3
VR3
J1
CAL
RUN
Figure 3-3. Electronics Validation Component Locations
J1 CAL/RUN jumper. Place in the
CAL position for validation, return to
RUN position for normal operation.
Potentiometer VR3
Hazardous-Area Enclosures
Potentiometer VR3
J1 CAL/RUN jumper. Place in the
CAL position for validation, return to
RUN position for normal operation.
IM-78S-B 3-13
Page 40
Chapter 3 Operation Series 780S Instruction Manual
Electronics Validation Procedure
1. Verify the flow meter is off line from any remote communications. Make sure the meter’s user full scale setting is the same as
the factory full scale setting. If not, adjust the user full scale
Caution!
Before beginning this
procedure, make sure the
flow meter is not actively
monitoring or reporting to
any master control sys-
tem. Any adjustment to
the electronics will cause
direct changes to flow
control settings.
value as needed.
2. Locate the Calibration Certificate supplied with the flow meter.
Record in Table 3-1 the five bridge voltage values, the output
(VDC or mA) values and the indicated flow values.
3. Remove power from the flow meter. Remove the cover(s) of the
flow meter enclosure to access the wiring terminal block and the
Smart electronics device.
4. Set the multimeter to the 20 volt range. Connect to BV(+) and
BV(–) terminals on the flow meter terminal block.
5. Move the J1 Cal/Run jumper on the Smart electronics device to
the CAL position. Locate potentiometer VR3 on the Smart electronics device. Turn on power to the flow meter.
6. Adjust potentiometer VR3 until the multimeter matches the first
bridge voltage point (the value must be ± 0.002 VDC of the
bridge voltage point).
7. Record the resulting flow shown on the optional LCD display in
Table 3-1. If not using a display or if you prefer to validate one
of the analog output signals, move the multimeter + connection
to Vout (+). Record the resulting output voltage in Table 3-1. If
using a 4-20 mA calibrated meter, set the multimeter to read current and connect the meter to read the mA signal in your connected loop. Record the resulting current output in Table 3-1.
8. Repeat Step 6 and Step 7 to record the results of the remaining
four bridge voltage validation points in Table 1. Compare the values recorded in Table 3-1. Indicated values must be within the
flow meter’s stated accuracy shown on the Calibration Certificate.
9. When data collection is complete, turn off power to the flow meter. Disconnect the multimeter from the flow meter terminal block.
10. Place the J1 Cal/Run jumper in the RUN position. Make sure the
jumper is securely in place before resuming flow meter operation. Replace the flow meter cover(s).
3-14 IM-78S-B
Page 41
Series 780S Instruction Manual Chapter 3 Operation
Calibration Certificate Values Validation Test Results
Sample
Point
Bridge
Voltage
Indicated
Flow
Output
(V or mA)
Indicated
Flow
(LCD)
Flow
Meter
Stated
Accuracy
Output
(V or mA)
Flow
Meter
Stated
Accuracy
0%
25%
50%
75%
100%
Table 3-1. Electronics Validation Results
Sensor Validation Procedure
1. Locate the Ro temperature (measured resistance at 0°C) value and
the Alpha value shown on the Calibration Certificate supplied with
the flow meter.
2. Turn off power to the flow meter. Allow a 6 minute
Warning!
Do not power the flow
meter with the sensor
jumper disconnected.
This could cause over-
heating of the sensors
and/or damage to the
electronics.
cool-down before continuing.
3. Remove the cover of the flow meter enclosure to access the sensor
connection points. Remove the four-position jumper from J5, J6,
J7 and J8 (see below for location).
Smart Electronic Device
NEMA 4X Enclosures
Terminal Board
Hazardous-Area Enclosures
IM-78S-B 3-15
1
20
2
19
3
18
4
17
5
16
6
15
7
14
8
13
9
12
10
11
J5 temperature
J6 temperature
J7 velocity
J8 velocity
Remove jumper, measure
on RIGHT ROW of pins
Figure 3-4. Sensor Validation Component Locations
J5 temperature
J6 temperature
J7 velocity
J8 velocity
Remove jumper,
measure on LEFT
ROW of pins
Page 42
Chapter 3 Operation Series 780S Instruction Manual
4. Set the multimeter to read Ohms in the 2K range. Connect the
multimeter to the terminals of J5 and J6 (temperature sensor).
Measure the resistance between J5 and J6 and record the temperature sensor resistance (in Ohms) in Table 3-2.
5. Set the multimeter to read in the 200 Ohm range. Connect the multimeter to terminals of J7 and J8 (velocity sensor). Measure the resistance between J7 and J8 and record the velocity sensor resistance (in Ohms) in Table 3-2.
6. Use the measured resistance values and the Ro and Alpha Ro
values from the Calibration Certificate to calculate the temperature for each sensor as follows:
R – R
T =
Alpha x R
Where
T = degrees Celsius
R = measured sensor resistance
R = resistance at 0° C (from the Calibration Certificate)
o
Alpha = value unique to each sensor (from the Calibration Certificate)
o
o
7. Compare the results recorded in Table 3-2. The sensors are validated if they are within 10 degrees Celsius of each other.
8. Disconnect the multimeter and replace the four-position jumper on
the sensor terminals. Make sure the jumper is securely in
place before applying power. Replace cover.
Temperature Sensor
Resistance
Velocity Sensor
Resistance
Table 3-2. Sensor Validation Results
T
(from equation)
T
(from equation)
3-16 IM-78S-B
Page 43
Series 780S Instruction Manual Chapter 4 Troubleshooting & Repair
Chapter 4 Troubleshooting and Repair
Troubleshooting the Flow Meter
Begin hardware troubleshooting by verifying the following facilities
issues are correct. These areas impact system operation and must be
corrected prior to performing any flow meter inspections.
Warning!
Before attempting any flow
meter repair, verify that the
line is not pressurized.
Always remove main power
before disassembling any
part of the mass flow meter.
1. Verify the incoming power to the flow meter is present and of
the correct voltage and polarity.
2. Check the flow meter wiring for correct connections as described in Chapter 2.
3. Verify the flow meter is installed with the correct number of upstream pipe diameters as shown on page 2-2.
4. Verify the flow direction indicator is correctly aligned pointing
downstream of flow.
5. Make sure there are no leaks in the line being measured.
After verifying the factors above, follow the troubleshooting procedures outlined on the next page. If you need to return the flow meter
to the factory, see page 4-3 for return shipping instructions.
Flow Meter Calibration
Sierra Instruments maintains a fully-equipped calibration laboratory.
All measuring and test equipment used in the calibration of Sierra
meters are traceable to NIST standards. Sierra is ISO-9001 registered and conforms to the requirements of ANSI/NCSL-Z540 and
ISO/IEC Guide 25. If the flow body or electronics have been damaged or you simply want to have the flow meter re-calibrated, contact the factory for return shipping instructions. Calibration must be
performed by qualified personnel using NIST-traceable equipment.
IM-78S-B 4-1
Page 44
Chapter 4 Troubleshooting & Repair Series 780S Instruction Manual
Problem Possible Cause Solution
Velocity measurement is
erratic or fluctuating
Velocity measurement
seems too high or low
No response to flow from
sensor assembly
Very erratic or non-uniform flow Follow installation requirements shown
in Chapter 2
Moisture present in gas flow Install a water trap or filter upstream of
the flow meter sensor
Flow conditioning plates are not
upstream of the sensor
Sensor component broken Return to factory for replacement
Malfunction in system
electronics
Ground loop Check wiring, see Chapter 2
Sensor assembly not aligned
correctly to flow
Flow conditioning plates are not
upstream of the sensor
No power Turn on power to the flow meter
Correct flow meter orientation
Return to factory for evaluation
Correct alignment with the flow indicator
pointing downstream in the direction of
flow
Correct flow meter orientation
Low flow cutoff setting too high Correct low flow cutoff programming
using the Smart Interface software.
Flow rate below meter’s minimum
flow rating
Flow has exceeded the maximum
range of the flow meter
Sensor failure Return to factory for evaluation
Printed circuit assembly defective Return to factory for evaluation
Contact factory for instructions
Set the user full scale to equal the factory full scale
Reduce flow below the maximum range
shown on the meter’s nameplate or contact the factory for re-calibration advice
4-2 IM-78S-B
Page 45
Series 780S Instruction Manual Chapter 4 Troubleshooting & Repair
Returning Equipment to Factory
Before returning any mass flow meter to the factory, you must request and complete a Sierra Calibration/Repair Data Sheet. To obtain
the data sheet contact Customer Service at:
(800) 866-0200 or (831) 373-0200 in the US
or +31(0)20-6145810 in Europe.
Return shipments to:
USA Headquarters
Sierra Instruments Service Department
5 Harris Court, Building W
Monterey, CA 93940
European Headquarters
Sierra Instruments b.v. Service Department
Bolstoen 30A
1046 AV Amsterdam, The Netherlands
When returning a component, make sure to include the completed
Calibration/Repair Data Sheet with the shipment.
IM-78S-B 4-3
Page 46
Chapter 4 Troubleshooting & Repair Series 780S Instruction Manual
4-4 IM-78S-B
Page 47
Series 780S Instruction Manual Appendix A Specifications
Appendix A Product Specifications
Performance Specifications
Accuracy ± 2% of reading from 10 to 100% of calibrated range
Repeatability ± 0.2% of full scale
Temperature Coefficient ± 0.02% of reading per °F within ± 50°F of customer specified conditions
Pressure Coefficient Negligible when within ± 50 psig (± 3.4 barg) of customer specified conditions
Response Time One second to 63% of final velocity value
Operating Specifications
Gases Most gases compatible with 316L stainless steel (consult factory)
Mass Flow Rates
Dual Calibration User-selectable dual ranges or two different gases
Gas Pressure 150 lb flange or PN16 DIN (–40° F to 100° F): 230 psig (15.9 barg) maximum
Gas & Ambient Temperature Gas...............–40° to 250°F (–40° to 120°C) Optional –40° F to 450° F
± 0.5% of full scale below 10% of calibrated range
± 0.03% of reading per °F within ± 50°F to 100°F of customer specified conditions
±0.04% of reading per °C within ± 25°C of customer specified conditions
±0.06% of reading per °C within ± 25°C to 50°C of customer specified conditions
Air Flow Ranges
Pipe Size Minimum Maximum
scfm (nm3/hr) scfm (nm3/hr)
1/4-inch 0–0.5 (0–0.7) 0–9 (0–14)
1/2-inch 0–2 (0–3.0) 0–40 (0–60)
3/4-inch 0–4 (0–5.9) 0–75 (0–120)
1-inch 0–6 (0–8.9) 0–120 (0–180)
1 1/2-inch 0–15 (0–22) 0–280 (0–440)
2-inch 0–23 (0–33) 0–470 (0–680)
3-inch 0–50 (0–74) 0–1000 (0–1500)
4-inch 0–90 (0–130) 0–1800 (0–2700)
6-inch 0–200 (0–300) 0–4000 (0–5900)
8-inch 0–350 (0–520) 0–7000 (0–10,000)
Notes: (1) Flow rates for air and nitrogen. Standard conditions: 70°F
and one atmosphere for scfm; 0°C and one atmosphere for
nm3/hr. Consult factory for other gases.
(2) Higher flow ranges available, consult factory.
(3) Maximum flow rates are limited for hazardous area
and high temperature versions, consult factory.
150 lb flange or PN16 DIN (250° F): 185 psig (12.8 barg) maximum
150 lb flange or PN16 DIN (450° F): 155 psig (10.7 barg) maximum
NPT (–40° F to 450° F): 500 psig (34 barg) maximum, 5 to 150 psig
(0.3 barg to 10 barg) optimum
(–40° C to 230° C) not available on 1/4 and 1/2-inch flow bodies
Ambient........–5° to 120°F (–20° to 50°C)
(1)
(2) (3)
IM-78S-B A-1
Page 48
Appendix A Specifications Series 780S Instruction Manual
Leak Integrity 1 X 10–4 atm cc/sec of helium maximum
Power Requirements 18 to 30 VDC (regulated), 625 mA maximum
Output Signal Linear 0-5 VDC or 0-10 VDC proportional to mass flow rate, 1000 Ohms mini-
Alarms User-adjustable low, high or window alarms
Displays Alphanumeric 2 x 12 digit backlit LCD
Totalizer Eight digits (99,999,999) in engineering units
Software Smart Interface Windows™-based software, minimum 8 MB of RAM,
Physical Specifications
Wetted Materials 316L stainless steel, Schedule 40 pipe flow body, Carbon steel flow bodies
Enclosure Hazardous-Area enclosure (IP67) and NEMA 4X (IP65) powder-coated cast aluminum
Electrical Connections Two 3/4 inch NPT Hazardous-Area enclosure (IP67)
Certifications* CE (all enclosures)
100 to 240 VAC , 50/60 Hz, 15 watts maximum*
*not available on NEMA 4X enclosures
mum load resistance, or Linear 4-20 mA proportional to mass flow rate, 700
Ohms maximum resistance (power supply dependent), optically isolated
Deadband adjustable with Smart Interface™ software
Relay rating...............Maximum 42 VAC or 42 VDC, 140 mA
Adjustable variables via on-board membrane buttons or with Smart Interface™ software
Adjustable variables...............Full scale adjustment (50 to 100%)
preferred 16 MB of RAM, RS-232 communication
available in some sizes
One 1/2 inch NPT NEMA 4X enclosure (IP65)
CSA (Explosion proof for Class I, Division 1, Groups B, C, D)
EEx (EEx dIIC T6...T2) Cenelec
FM (Explosion proof for Class I, Division 1, Groups B, C, D)
*Certifications pending, contact factory
Time response (0.1 to 7.2 seconds)
Correction factor setting (0.5 to 5)
Zero and span adjustments
A-2 IM-78S-B
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