Specifications

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Siemens FI 01 · 2015 US Edition
Temperature Measurement
Transmitters for rail mounting
SITRANS TW four-wire system, universal, HART
2
■ Integration
System configuration
Possible system configurations
The SITRANS TW transmitter as a four-wire rail-mounted device
can be used in a number of system configurations: as a stand-
alone version or as part of a complex system environment, e.g.
with SIMATIC S7. All device functions are available via HART
communication.
Communication options through the HART interface:
• HART communicator
• HART modem connected to PC/laptop on which the appropri-
ate software is available, e.g. SIMATIC PDM
• HART-compatible control system (e.g. SIMATIC S7-400 with
ET 200M)
■ Technical specifications
SITRANS TW
transmitter
Control system
or
Load
HART
communi-
cator
or
HART
modem
PC/laptop with
SIMATIC PDM
A
U
H
RS-232-C
SIMATIC S7-400
ET 200M
SIMATIC PDM
4...20 mA
Input
Selectable filters to suppress the
line frequency
50 Hz, 60 Hz, also 10 Hz for spe-
cial applications (line frequency
filter is similar with measuring fre-
quency)
Resistance thermometer
Measured variable Temperature
Measuring range Parameterizable
Measuring span
min. 25 °C (45 °F) x 1/scaling fac-
tor
Sensor type
• Acc. to IEC 751 Pt100 (IEC 751)
• Acc. to JIS C 1604-81
Pt100 (JIS C1604-81)
• to DIN 43760
Ni100 (DIN 43760)
• Special type (R
RTD
 500 ) Multiples or parts of the defined
characteristic values can be
parameterized (e.g. Pt500, Ni120)
Characteristic curve Temperature-linear, resistance-lin-
ear or customer-specific
Type of connection • Normal connection
• Sum or parallel connection
• Mean-value or differential con-
nection
Interface 2, 3 or 4-wire circuit
Measuring range limits Depending on type of connected
thermometer (defined range of
resistance thermometer)
Sensor breakage monitoring Monitoring of all connections for
open-circuit (function can be
switched off)
Sensor short-circuit monitoring
Parameterizable response thresh-
old (function can be switched off)
Resistance-based sensor, potenti-
ometer
Measured variable Actual resistance
Measuring range
Parameterizable
Measuring span min. 10 
Characteristic curve Resistance-linear or customer-
specific
Type of connection
• Normal connection
• Differential connection
• Mean-value connection
Interface 2, 3 or 4-wire circuit
Input range
0 ... 6000 ;
with mean-value and difference
circuits: 0 ... 3000 
Sensor breakage monitoring
Monitoring of all connections for
open-circuit (function can be
switched off)
Sensor short-circuit monitoring
Parameterizable response thresh-
old (function can be switched off)
© Siemens AG 2015