Sierra TM500 User manual

TM500 Thermal Mass Flow Meter
Instruction Manual
Document: S-IM-TM500 | Rev B_PN 110069
www.sierrainstruments.com

2

3
Disclaimer TM500
GLOBAL SUPPORT LOCATIONS: WE ARE HERE TO HELP!
For Global Service Centers, go to http://www.sierrainstruments.com/facilities.html
CORPORATE HEADQUARTERS
5 Harris Court, Building L Monterey, CA 93940
Phone [phone] +1.800.866.0200
[email protected]
www.sierrainstruments.com
EUROPE HEADQUARTERS
Bijlmansweid 2 1934RE Egmond aan den Hoef
The Netherlands
Phone [phone] Fax [phone]
[email protected]
ASIA HEADQUARTERS
Second Floor Building 5, Senpu Industrial Park
25 Hangdu Road Hangtou Town
Pu Dong New District, Shanghai, P.R. China
Postal Code 201316
Phone: + 8621 5879 8521 Fax: [phone]
© COPYRIGHT SIERRA INSTRUMENTS 2023
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
TM500™, TM-Cal™, Gas-Mix ™, FlowTrak™, TM500-View Software™ and DigiSense™ are
trademarks of Sierra Instruments, Inc. Other product and company names listed in this
manual are trademarks or trade names of their respective manufacturers.

4
DisclaimerTM500
Warning and Cautions
General Safety Information
We use caution and warning statements throughout this book to draw your attention to
important information.
Symbol Key
Symbol Symbol Meaning Description
Warning
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.
Caution/Note
This statement appears with information
that is important for protecting your
equipment’s performance. Read and follow
all cautions that apply to your application.
• 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! Hot tapping must be performed by a trained professional. U.S. regulations
often require a hot tap permit. The manufacturer of the hot tap equipment and/or the
contractor performing the hot tap is responsible for providing proof of such a permit
• Warning! All wiring procedures must be performed with the power O.
• 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! 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.
WARNING

5
Disclaimer TM500
• Caution! Before making adjustments to the TM500, 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! All flow meter connections, isolation valves and fittings for hot tapping must have
the same or higher pressure rating as the main pipeline.
• Caution! The flow meter electronics and sensor probe have been manufactured and
calibrated to operate as a unit. The flow meter will not operate properly if parts are replaced
from another meter.
• 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
CAUTION

6
DisclaimerTM500
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
or distributor. 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. Installation information can be found in Chapter 2 of this
manual.
If the problem persists, contact Sierra Instruments by e-mail (see inside front cover). For urgent phone
support you may call [phone] between 8:00 a.m. and 5:00 p.m. PST. In Europe, contact Sierra
Instruments Europe at [phone]. In the Asia-Pacific region, contact Sierra Instruments Asia at
[phone]. When contacting Technical Support, make sure to include this information:
• The serial number (marked on the meter's label)
• The firmware version (visible on the display at startup)
• The problem you are encountering and any corrective action taken
• Application information (flow range, gas, pressure, temperature and piping configuration)
Using This Manual
This manual provides information needed to install and operate the Series TM500 Mass Flow Meter.
Additional Resources
Visit Sierrainstruments.com for additional resources. Note: the most current versions of the TM500
documents can be found at https://www.sierrainstruments.com/products/downloads.html.

7
TM500
Table of Contents
1. Introduction p. 11-21
a. Quick Start Guide .........................................................................p. 9
b. Menu Trees ..............................................................................p. 11
c. General ................................................................................ p. 19
2. Installation (Mechanical) p. 22-33
a. Lateral Placement........................................................................p. 23
b. Welding Branch Outlet ...................................................................p. 25
c. Installation Depth ........................................................................p. 26
d. Mounting Instructions ....................................................................p. 28
e. Orientation..............................................................................p. 29
f. Retractor Installation .......................................................................p. 31
3. Wiring (Electrical) p. 35-48
a. Wiring Access ...........................................................................p. 35
b. Input Power .............................................................................p. 37
c. Signal Wiring and HART Communication Option .............................................p. 39
d. Pulse/Alarm Wiring (optional feature) ....................................................... p. 41
e. RS485 Wiring ...........................................................................p. 44
f. HART Handheld Wiring....................................................................p. 45
g. Remote Wiring ..........................................................................p. 46
4. Operation (Standard Operation) p. 49-73
a. Start Up ................................................................................p. 49
b. Programming............................................................................ p. 51
c. TM-Cal™ ................................................................................p. 67
d. Gas-Mix ™ ...............................................................................p. 70
5. Communication Protocols p. 74-86
a. Modbus RTU (RS485).....................................................................p. 74
b. HART with DDL..........................................................................p. 84
Table of Contents

TM500
8
Table of Contents
6. Maintenance p. 88-96
a. Safe Removal of Meter from Retractor ......................................................p. 90
b. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . p. 94
7. Appendices p. 99-115
a. Specifications ...........................................................................p. 99
b. Agency Approvals ......................................................................p. 102
c. Dimensions ............................................................................p. 103
d. Terms and Conditions of Sale .............................................................p. 114
e. Returning your meter.....................................................................p. 114
8. Definitions p. 114
9. Index p. 115

Use the table below as a guide while using the worksheet on the next page to record your notes.
NOTE! Please read the entire quick-start procedure before beginning installation.
TM500
TM500
9
Introduction
3 PULSE (+)
4 PULSE (-)
7 COMMON
6 Tx/Rx (-)
5 Tx/Rx (+)
2 SWITCH INPUT (-)
1 SWITCH INPUT (+)
POWER (+) 1
POWER (-) 2
4-20mA #1 (+) 3
4-20mA #1 (-) 4
4-20mA #2 (+) 5
4-20mA #2 (-) 6
TS2
TS1
F1
J1
USB
0.75A
W1
TERMINATION
TP1
TP2
EARTH GROUND
POWER
#4
#6
#3
#5
#2
Cable Shield
Electronics Enclosure
RED WHT
BLU YEL
Probe Sensor Wired By Fox
SENSOR
Remote Enclosure
#7
#8
#1
Splice
Green Wire
Shield Wire (insulate)
F1 F2 F3 F4
Initializing...
F1 F2 F3 F4
Initializing...
3 PULSE (+)
4 PULSE (-)
7 COMMON
6 Tx/Rx (-)
5 Tx/Rx (+)
2 SWITCH INPUT (-)
1 SWITCH INPUT (+)
POWER (+) 1
POWER (-) 2
4-20mA #1 (+) 3
4-20mA #1 (-) 4
4-20mA #2 (+) 5
4-20mA #2 (-) 6
TS2
TS1
F1
J1
USB
0.75A
W1
TERMINATION
TP1
TP2
TM500Customer PLC or DCS
+12 TO 24VDC
PULSE OR ALARM OUTPUT
12 TO 24VDC RETURN
+
-
2.4K OHM TYPICAL WITH 24VDC POWER
1.2K OHM TYPICAL WITH 12VDC POWER
ID OUTER
DIAMETER
FLOW
4X = INLINE
10X = INSERTION
8X = INLINE
15X = INSERTION
PIPE ID MIN.
INDICATOR:
- POINT IN DIRECTION
OF FLOW
- LOOSEN SET SCREWS TO
ROTATE HOUSING ±90º, ±180º
- TIGHTEN SET SCREWS
WHEN DONE
FLOW
FLOW
PIPE
0.73"
(18.5 mm)
L
C
F1 F2 F3 F4
ACCESS THE
DISPLAY BY
UNSCREWING
COVER
REMOVE SCREWS
ON DISPLAY TO
ROTATE DISPLAY
±180°
1. Record inside diameter (ID). Ensure the actual pipe ID
matches the pipe ID shown on the factory calibration
certificate. If IDs do not match, refer to "Pipe Diameter" on
page 61.
2.
Record up/downstream straight-pipe requirements based on
Pipe ID and meter style (insertion or inline). [refer to p. 23]
3.
The Flow Direction Indicator must point in the direction of
flow.
The housing can be rotated for a better view of the meter's
display. Note that the 2 set screws must be loosened before
the housing will turn. [refer to p. 29]
4.
Ensure correct probe depth setting. If using 1 ½" size pipe,
please see note on p. 26.
5.
If needed, the orientation of display can be rotated in 90°
increments for a better view.
[refer to p. 30 for more information]
6. Ensure power wiring [p. 37] and 4-20mA wiring [p. 39 -
p. 40] properly connected. [refer to Wiring section p. 35
for more information]
7.
Ensure remote wiring is correct if remote option ordered.
[refer to p. 46 - p. 48 for more information]
8.
Verify you have the proper output signal wiring
[refer to p. 39 - p. 45 for more information]
9.
Apply power to the flow meter.
10. Check the remaining flow meter settings by accessing the meter settings either through the front panel of the
display or by using the TM500-ViewTM software. Record the settings in the spaces given for items A - F on
the following page.
Quick Start Guide

Item to verify Serial Number: Serial Number: Serial Number: Serial Number:
1. What is the Pipe ID? ID = ID = ID = ID =
2. Calculate the Upstream/Downstream
straight-pipe requirements
UP =
DN =
UP =
DN =
UP =
DN =
UP =
DN =
3.
Is the flow indicator pointed in direction
of flow?
Must the housing be rotated for easy
viewing?
Y / N
Y / N
Y / N
Y / N
Y / N
Y / N
Y / N
Y / N
4. Is the probe depth setting correct? Y / N Y / N Y / N Y / N
5. Have you rotated the display for easier
viewing? Y / N Y / N Y / N Y / N
6. Verify proper power wiring
7. Verify proper remote wiring (if ordered)
8. Verify proper input/output wiring
After applying power to your meter, check items A - F below by accessing the meter settings either
through the front panel of the meter's display or by using the TM500-ViewTM Software.
A. Which flow units have been set in
meter? (SCFM, KG/H, etc..)
B. Correct values for reference
temperature and pressure? Y / N Y / N Y / N Y / N
C. Confirm the pipe ID listed above same
as "Pipe_id="
D. Verify the 1st 4mA and 20mA meter
settings
4mA =
20mA =
4mA =
20mA =
4mA =
20mA =
4mA =
20mA =
E. Verify the 2nd 4mA and 20mA meter
settings
4mA =
20mA =
4mA =
20mA =
4mA =
20mA =
4mA =
20mA =
F. Confirm the correct gas is selected for
your application in theGas-Mix ™ menu
Before applying power to your meter, use this worksheet to record your notes.
If you are experiencing any problems after completing this procedure, please call the Sierra Instruments Service Department
at 831-373-0200 to review this information.
Your Notes:
10
TM500 Quick Start Guide

MAINMENU
I/OFLODSPEXIT
Comm=Modbus
NXTOK
None
Modbus
HART
mA=Temp
NXTOK
20mACnt=52921
CHGOK
4mACnt=2515
CHGOK
20mA=200°F
CHGOK
4mA=10°F
CHGOK
Temp
Flow
AnalogOutputs
Baud=9600
NXTOK
Parity=NONE
NXTOK
Address=02
CHGOK
1200
2400
4800
9600
19200
38400
57600
76800
115200
NONE
ODD
EVEN
01‐247
Entermenubyscollingtodisplay4
andenteringthepassword
mAFault=Notuse
NXTOK
Notuse
3.6mA
21mA
Communication
Level2
password
I/OMENU
I/OCOM420EXIT
Comm=Hart
OK
Address=0
CHGOK
0‐63
Modbus
Only
HART
Only
SET4‐20mA
CH1CH2EXIT
20mACnt=52921
CHGOK
4mACnt=2515
CHGOK
20mA=2345.6SCFM
CHGOK
4mA=0SCFM
CHGOK
mAFault=Notuse
NXTOK
Notuse
3.6mA
21mA
Level2
password
NOTE! Some menus will only be available with a
level 2 password.
NOTE! Menu tree boxes are populated with
example values.
Display Menu, p. 15
Flow Menu 1, p. 13
Digital Output
Menu, p. 12
TM500TM500
11
Introduction
Fig. 1.1: TM500 Menu Tree - Main Menu

OUT= Pulse
NXT OK
Not used
Pulse
HiFloAlm
LoFloAlm
HiTempAlm
LoTempAlm
System Alarm
PULSE OUTPUT
P/U U/P FEQ EXIT
PLS/UNT=2
CHG OK
UNT/PLS=0.5
CHG OK
MaxFreq=100Hz
CHG OK
MaxFlo=5000 SCFM
CHG OK
HiFloAlm=500 SCFM
CHG OK
LoFloAlm=100 SCFM
CHG OK
HiTmpAlm=250° F
CHG OK
LoTmpAlm=10 F
CHG OK
High Flow Alarm
Low Flow Alarm
High Temp Alarm
Low Temp Alarm
Select 1 of 3
methods to scale
the pulse output
Pulse
OUT= HiFloAlm
NXT OK
OUT= LoFloAlm
NXT OK
OUT= HiTempAlm
NXT OK
OUT= LoTempAlm
NXT OK
System Alarm
OUT= System Alm
NXT OK
Set I/O
OUT INP EXIT
Alarm output
MAIN MENU
I/O FLO DSP EXIT
Inp= Not Used
NXT OK
Not used
Tot Reset
I/O MENU
I/O COM 420 EXIT
NOTE!A value of 0 disables the alarms
(See Flow Menu 2, p. 14, for more alarm settings)
TM500TM500 Introduction
12
Fig. 1.2: TM500 Menu Tree - Digital Outputs and Input

FLOW MENU 1
DGN UNT FM2 EXIT
DIAGNOSTIC
SIM TM-Cal EXIT
FloSim=0 SCFM
CHG OK
TmpSim=0 ° F
CHG OK
ENABLE SIM?
YES NO
FLO UNT=SCFM
NXT OK
SCFM
SCFH
NM3/H
NM3/M
KG/H
KG/M
KG/S
LBS/H
LBS/M
LBS/S
NLPH
NLPM
MMSCFD
LBS/D
SLPM
NLPS
MSCFD
SM3/H
MT/H
NM3/D
MMSCFM
SCFD
MCFD
SM3/M
SM3/D
TMP UNT=° F
NXT OK
Deg F
Deg C
TmpRef=60 °F
CHG OK
PRES UNT=Psia
NXT OK
PresRef=14.73
CHG OK
mmHG
Psia
bara
Simulate Flow?
YES NO
Simulate Temp?
YES NO
MAIN MENU
I/O FLO DSP EXIT
Flow Menu 2 Menu, p. 14
TM-Cal™ Menu, p. 16
TM500TM500
13
Introduction
Fig. 1.3: TM500 Menu Tree - Flow Menu 1

FLOWMENU2
GASSPCPRMEXIT
Kfact=0%
CHG OK
RESETCRC?
YES NO
Cutoff=12.5SCFM
CHG OK
Pipe_id=4.026In
CHG OK
Filter=0.8Sec
CHG OK
Parameters
Flowcutoffinselectedunits
Pipeidininchesormm
FlowFilterinseconds
Min=0.8,max=10
HiFloAlm=0SCFM
CHG OK
LoFloAlm=0SCFM
CHG OK
HiTmpAlm=0°F
CHG OK
LoTmpAlm=0°F
CHG OK
Level2
RESTOREDATABASE?
YES NO
MAINMENU
I/OFLODSPEXIT
FLOWMENU1
DGNUNTFM2EXIT
 Thesealarmscanbeusedwithoutthedigitaloutputassignedto
thealarm.
 Ifthatisthecase,thealarmstatuswillonlybeshownonthe
display,throughserialcommunicationorBioViewTM.
 Ifthedigitaloutputisassignedtoanalarm,changingthevalue
herewillchangethatsetting.
 Avalueof0disablesthealarm.
Gas-Mix ®Menu, p. 17
TM500TM500 Introduction
14
Fig. 1.4: TM500 Menu Tree - Flow Menu 2

DISPLAY/PASSWORD
DSP PSWEXIT
DSP1L1=FLorate
NXT OK
FLorate
Total
Elps
Temp
Alarm
DSP1L2=Total
NXT OK
DSP2L1=Temp
NXT OK
DSP2L2=Elps
NXT OK
ALTERNATE=Off
NXT OK
On
Off
PASSWD=1234
CHG OK
FLorate
Total
Elps
Temp
Alarm
FLorate
Total
Elps
Temp
Alarm
FLorate
Total
Elps
Temp
Alarm
Whenalternate
"ON",flashes
betweenthe2
displays
Display1
Line1
Display2
Line1
Display2
Line2
MAINMENU
I/OFLODSPEXIT
Display1
Line2
NOTE!All readings updated every second
• Flo Rate = Flow rate of process gas
• Total = Total flow of process gas
• Elps = Elapsed time since reset of flow total
• Temp = Temperature of process gas
• Alarm = Notification of errors; diagnostic errors
TM500TM500
15
Introduction
Fig. 1.5: TM500 Menu Tree - Display Menu

DIAGNOSTIC MENU
SIM TM-Cal EXIT
TM-Cal MENU
VER EXIT
Verifying TM-Cal
Please Wait
Verifying TM-Cal
0.512 T=123
TM-Cal =0.259
Pass OK
Displays the test’s
count down mer
Displays a number value
during test
VERIFY TM-Cal?
YES NO
TM-Cal=0.911
Warning OK
TM-Cal=2.321
Fail OK
FLOW MENU 1
DGN UNT FM2 EXIT
MAIN MENU
I/O FLO DSP EXIT
Flo: Hold Value
NXT EXIT OK
Hold Value
Go to zero
Take Control
off-line EXIT OK
TM-Cal Fail
Greater than ±1.0
TM-Cal Pass
Less than ±0.80
TM-Cal Warning
Between ±0.80 to ±1.0
Choosing “Hold Value” will
retain the last flow value while
test is being performed.
TM500TM500 Introduction
16
Fig. 1.6: TM500 Menu Tree - TM-Cal™ Menu

FLOW MENU 2
GAS PRM EXIT
Hydrogen = 0 %
CHG OK
GAS=Mix
NXT OK
Pure Gas
Mix
Propane = 0 %
CHG OK
CO2 = 25.5 %
CHG OK
Helium = 0 %
CHG OK
Argon = 0 %
CHG OK
MAIN MENU
I/O FLO DSP EXIT
FLOW MENU 1
DGN UNT FM2 EXIT
Methane = 65.5 %
CHG OK
Oxygen = 0 %
CHG OK
Butane = 0 %
CHG OK
Nitrogen = 5 %
CHG OK
Be sure mixture
equals 100%.
Err: Mix= 96%
CHG
Shows only if gas mix
does not equal 100.0%.
Gas Mix 100%
CHG OK
Shows only if no error is
detected. Pressing OK
allows exit to menu.
OR
Air = 0 %
CHG OK
GAS= Mix
NXT OK
Methane
CO2
Nitrogen
Air
Natural Gas
Argon
Propane
Helium
Oxygen
Butane
Hydrogen
Ethane
Ethylene
Propylene
GAS=Methane
NXT OK
Ethane = 0 %
CHG OK
= 0 %
CHG OK
= 0 %
CHG OK
Pure Gas
Ethylene
Propylene
TM500TM500
17
Introduction
Fig. 1.7: TM500 Menu Tree - Gas-Mix ™ Menu

TM500TM500 Introduction
18
3124.6 SCFM
csv = 0.3432 Volt
Press F1 and F2 at the same me to enter the Engineering Screens
Press F4 to return to normal mode
Display 10
Display 19
Pulse=1234.5 cnt
mA_420=234 cnt
Elp=12.5 HR
Stat(hex)=2800
Alarm=None
TM500 v8.3
MB_Sn=P23949
BB_Sn=P23945
MTR_Sn=123456
SNS_Sn=234567
TmpHi=0.0 °F
TmpLo=0.0 °F
Pwr_Cycl=24
Err_tot=0
FloHi=0.00 SCFM
FloLo=0.00 SCFM
TM-Cal = 0.1
Press F1 tonavigate up
Press F2 tonavigate down
Press F4 toreturn tonormalmode
Flow rate measured bythe meter
Current Sense Voltage of sensor circuit
Digitalcontrol counts of Pulse output
Digitalcontrol count of 4-20mA output
Elapsed me of meter opera on
Meter funcon and opera on status code
Meter’s acve alarms
Firmware version of meter
Main board serial number
Bridge board serial number
Meter serial number
Sensor serial number
Alarm Seng
Alarm Seng
Alarm
Alarm
Totalnumber of power cycles
Number of errors in totalflow measuremen
t
TM-CalTM measurement value
Press NXT (F1) tonavigate down
Press PRV (F2) tonavigate back up
1014.1 BTU/Ft3
NXT PRV EXIT
DNS=0.6800 Kg/M3
PRV EXIT
Methane
Methane
CO2
Nitrogen
Air
Natural Gas
Argon
Propane
Helium
Oxygen
Butane
Hydrogen
Ethane
Ethylene
Propylene
100%
OK
Flow: SCFM
NXT PRV EXIT
Temp: °F
NXT PRV EXIT
Ref Press: Psia
NXT PRV EXIT
Ch1: Flow
NXT PRV EXIT
20 Ma=706.29
NXT PRV EXIT
4 Ma=0.00
NXT PRV EXIT
FloHi=0.00 SCFM
NXT PRV EXIT
FloLo=0.00 SCFM
NXT PRV EXIT
TmpHi=0.0 °F
NXT PRV EXIT
TmpLo=0.0 °F
NXT PRV EXIT
RefP=14.73 psia
NXT PRV EXIT
RefT=60.00 °F
NXT PRV EXIT
Kfact=0.0%
NXT PRV EXIT
Cutoff=12.5 SCFM
NXT PRV EXIT
PipeID=4.03 In
NXT PRV EXIT
Flt=0.80 Sec
NXT PRV EXIT
MTR_Sn=123456
NXT PRV EXIT
TM500 v8.3
NXT PRV EXIT
Release: 07_04_23
PRV EXIT
ENG Screen 1
GAS CFG VAL EXIT
ENG Screens
ENG1 ENG2 EXIT
TM-Cal=0.1
NXT PRV EXIT
TM-Cal=Pass
NXT PRV EXIT
NXT PRV EXIT
PRV EXIT
P TM-Cal=Pass
P TM-Cal=0.14
Fig. 1.8: TM500 Menu Tree - Engineering Screens
Fig. 1.9: TM500 Menu Tree - Reset Flow Total
F3 & F4 pressed at the same time will
initiate a "Total" reset
Reset Total?
NO YES
Resetting total

Welcome
Thank you for purchasing the TM500 Thermal Gas Mass Flow Meter from Sierra Instruments. The
TM500 is one of the most technically advanced flow meters in the world. Extensive engineering
eort has been invested to deliver advanced features, accurate measurement performance and
outstanding reliability.
This instruction manual contains the electrical and mechanical installation instructions as well as
details for programming, maintaining and troubleshooting the meter. This manual is divided into
the following sections: Introduction, Installation, Wiring, Operation, Communications, Maintenance,
Appendices, Definitions, and Index.
Theory of Operation
The TM500 is an innovative thermal mass gas flow meter and temperature transmitter. It is
microprocessor-based and field programmable. The TM500 thermal sensor operates on the law
that gases absorb heat. A heated sensor placed in an air or gas stream transfers heat in proportion
to the stream’s mass velocity. There are two sensor elements. One sensor element detects the
gas temperature and a second element is maintained at a constant temperature above the gas
temperature. The energy transferred from the heated element is proportional to the mass flow
velocity. The TM500 flow meter maintains accurate flow measurement over a large temperature and
pressure range.
Mass Flow
The TM500 measures mass flow; an advantage over other flow meters which measure volumetric
flow rate. Volumetric flow is incomplete because temperature and pressure are unknown and
must be measured separately. For example, the mass flow of a gas depends on its temperature
and pressure. As temperature and pressure changes, the gas volume changes but not its mass.
Therefore a device measuring mass flow is independent of temperature and pressure changes. The
TM500 provides a direct measurement of gas flow in Mass units (kg/hr, lb/hr), standard units (SCFM,
SLPM) or normal units (NM3/hr, NLPM) with no additional temperature or pressure measurements
required.
Calibration Validation
Validate the calibration of the TM500 in the field using the TM-Cal™ test. The goal of Calibration
Validation is to provide operators with the ability to verify that the meter is capturing accurate data
at scheduled recalibration times - or at any time - instead of sending the meter back to the factory
for recalibration. By performing TM-Cal™ in the field, operators can verify that the meter is running
accurately by testing the functionality of the sensor and its associated signal processing circuitry.
This test can be done in the pipe under normal process conditions.
TM500
TM500
19
Introduction

Flow Calibration
Every Sierra Instruments flow meter is set to the customer's configuration at the factory using an App
ID which is generated by the on-line configurator. The App ID specifies the gas type, flow range, serial
communication and other settings in the meter. If these settings match the final customer application,
the meter is ready to use. Sierra maintains instrument calibration data on every flow meter. Calibration
files include details on process conditions, customer gas, line size and other information. All NIST-
traceable equipment utilized for the calibration procedure is identified on the Calibration Certificate,
which is sent with every flow meter.
I/O Description
The TM500 features two galvanically isolated 4-20mA analog outputs, HART communication (optional),
a pulse output, switch input and Modbus RTU (RS485) (optional). There is also a USB port for
interfacing with a laptop or computer. The first 4-20mA output can be used for HART communication.
The second 4-20mA output can be configured for flow rate or process gas temperature and can be
scaled by the user. The pulse output can be used for pulse or alarm and is programmable to represent
flow rate. The switch input can be configured to reset the flow totalizer and elapsed time.
TM500-View™ software interfaces to the USB port and is a free Sierra Instruments PC-based software
program that displays flow meter readings and permits flow meter configuration. The software is
available for download on the Sierra Instruments website.
TM500
TM500 Introduction
20