00825-0100-4329, Rev 02
Rosemount™ 327T Temperature
Transmitter
Quick Start Guide
August 2020
Quick Start Guide August 2020
Contents
Introduction.................................................................................................................................3
Installation................................................................................................................................. 11
Operation...................................................................................................................................16
Setting range for drW and drA....................................................................................................19
Troubleshooting........................................................................................................................ 20
Product certifications................................................................................................................. 22
Factory settings..........................................................................................................................23
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August 2020 Quick Start Guide
1 Introduction
The Rosemount 327T Temperature Transmitter detects media temperature
and converts it into an analog output signal (4 - 20 mA). The temperature
transmitter includes an IO-Link interface for configuring parameter settings
or viewing process and diagnostic data.
1.1 Getting started
Follow these steps to configure the temperature transmitter for normal
operation.
Procedure
1. Connect the temperature transmitter to a PC to set parameters using
IO-Link.
2. Set the standard unit of measurement in °F or °C (Uni). (See
Adjustable parameters)
3. Set the analog signal. (See Analog function)
• OU2: I = 4-20 mA or Ineg = 20-4 mA
• ASP and AEP: scaling of the measuring range.
4. Configure Drift Monitoring. (See Setting range for drW and drA)
• drW: drift threshold at which the temperature transmitter signals
"warning".
• drA: drift threshold at which the temperature transmitter signals
"alarm".
• ddr: Drift Monitoring Diagnostic delay.
5. Set which diagnostic cases the temperature transmitter signals using
drEd. (See Diagnostic cases)
• ON: only failure diagnostic cases
• ONdr: alarm and failure diagnostic cases
• OFF: warning, alarm, and failure diagnostic cases
6. Configure analog signal for diagnostic cases (FOU2). (See Adjustable
parameters)
• ON: 21.5 mA
• OFF: 3.5 mA
7. Configure switching signal for diagnostic cases in three-wire
operation (dOU1). (See Diagnostic function (three-wire))
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• dOU1: Output opens, closes, or pulsates; according to
configuration.
8. Configure output logic for diagnostic output in three-wire operation
(P-n). (See Adjustable parameters)
• pnp
• npn
9. Complete all other necessary parameter settings.
Postrequisites
Perform these tasks to complete setting up the transmitter:
• Mounting the transmitter
• Wire the Transmitter
• Operation
1.2 Functions and features
The temperature transmitter detects process temperature and converts it
into an analog output signal.
The temperature transmitter includes an IO-Link interface for configuring
parameter settings or viewing process and diagnostic data.
The transmitter operates in two-wire or three-wire operation modes. The
modes produce these output signals:
Operating mode
Two-wire Analog signal for temperature measurement and diagnostics
Three-wire • OUT1: switching signal for diagnostics and IO-Link
Output signals
communication
• OUT2: analog signal for temperature measurement and
diagnostics
1.2.1 Analog function
The temperature transmitter converts the measured temperature value into
an analog signal proportional to the temperature.
The temperature transmitter also uses the analog output to send diagnostic
messages (see Diagnostic function). Diagnostic messages interrupt the
transfer of the measured temperature value depending on the operating
mode and drEd. The transmitter modifies the analog output to the following
values according to NE43: 3.5 mA (FOU2 = On) or 21.5 mA (FOU2 = OFF).
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Depending on the OU2 setting, the analog signal is between these
measuring ranges in normal operation:
• I: 4-20 mA
• Ineg: 20-4 mA
The measuring range is scalable using these parameters:
• ASP: the analog start point and the measured temperature when the
analog signal is 4 mA (OU2 = I) or 20 mA (OU2 = Ineg)
• AEP: the analog end point and the measured temperature when the
analog signal is 20 mA (OU2 = I) or 4 mA (OU2 = Ineg).
Note
The minimum difference between ASP and AEP is 9°F (5°C).
If the measured temperature value is outside the scaled measuring range,
the analog signal is 20-20.5 mA or 3.8-4 mA (see Figure 1-1). When the
measured temperature value continues to increase or decrease, diagnostic
case 5 occurs. For more information, see Diagnostic cases.
Figure 1-1: Analog output with factory settings
• 1: Setting OU2 = I
• 2: Setting OU2 = Ineg
• MAW: initial value of the measuring range
• MEW: final value of the measuring range
• ASP: analog start point
• AEP: analog end point
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1.2.2 Diagnostic function
The temperature transmitter uses two different, thermally coupled sensor
elements (NTC, PT 1000) to automatically detect drifts and errors during
temperature measurement.
The temperature transmitter forms an average value using the individual
NTC and Pt 1000 measured values. That value determines the measured
temperature value and is the basis for Drift Monitoring Diagnostic (see Drift
Monitoring).
The temperature transmitter can detect other errors. Use the parameter
drEd to set which diagnostic cases the temperature transmitter signals. For
more information, see Diagnostic cases.
The analog signal provides diagnostic case messages in two-wire operations.
In three-wire operations, the switching signal provides diagnostic case
messages in addition to the analog signal.
Drift Monitoring
For Drift Monitoring Diagnostic, the temperature transmitter compares the
temperature deviation of sensor element 1 (NTC) and sensor element 2 (Pt
1000) to the average temperature value. The parameters drW (warning
threshold) and drA (alarm threshold) define the permissible temperature
deviation.
When values exceed these thresholds, the temperature transmitter triggers
drift monitoring and identifies a fault (see Diagnostic cases).
Figure 1-2: Drift monitoring example
Example: NTC sensor element (1) measures 149 °F and Pt 1000 sensor
element (2) measures 140 °F. The average value (3) is 144.5 °F, i.e. both
elements deviate by 4.5 °F. With setting drW = 4 °F and drA = 9 °F, the
temperature transmitter provides a warning message if drEd = OFF. In this
case, the temperature transmitter would not send an alarm message.
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For more information about configuring drW and drA, see Setting range for
drW and drA.
Note
Temperature difference of at most 0.18 °F (0.1 °C) can occur with sensor
elements because of standard manufacturing tolerances. This does not
affect the drift monitoring diagnostic.
Note
Large temperature changes in the medium might cause short-term
differences between the measured temperature values of both sensor
elements. To avoid short-term drift warnings, increase the drift warning
delay time (ddr).
Sensor backup
If one of the two sensors in the transmitter fails, the temperature transmitter
can use the remaining sensor for temperature measurement.
For more information on operating the temperature transmitter in backup
mode, see Troubleshooting.
Note
Drift monitoring is not possible if a sensor fails and sensor backup is active.
Diagnostic cases
The temperature transmitter identifies error scenarios with these diagnostic
cases.
For more information on parameters relating to diagnostic cases, see
Adjustable parameters or Drift Monitoring.
Table 1-1: Warnings
Diagnostic
number
1 The temperature deviation exceeded the drift warning
2 The temperature of the internal electronics exceeded the limit
Description
threshold (drW).
of 257 °F (125 °C).
Table 1-2: Alarms
Case number Description
3 The temperature deviation exceeded the drift alarm threshold
4 One of the two sensor elements failed.
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(drA).
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Table 1-2: Alarms (continued)
Case number Description
5 The measured temperature value is outside the allowable
6 The supply voltage is outside the operating range.
(1) For 2-wire operation, no diagnostic message is provided in case of low voltage
(see Diagnostic function (two-wire)).
measuring range.
(1)
Table 1-3: Failures
Case number Description
7 The temperature deviation exceeded the drift failure threshold
8 An error occurred while setting parameters using IO-Link.
9 Both sensor elements failed or general electronics problems.
(drF).
Diagnostic function (two-wire)
In two-wire operation, the temperature transmitter uses the analog output
for temperature measurement and diagnostics.
drEd configures the diagnostic cases that the temperature transmitter
signals using the analog output:
• ON: Limits the diagnostic messages to only failure messages. The
temperature transmitter will signal only diagnostic cases 7-9.
• ONdr: Limits the diagnostic messages to alarm and failure messages. The
temperature transmitter will signal only diagnostic cases 3-9.
• OFF: Allows all diagnostic messages. The temperature transmitter will
signal all diagnostic cases.
For more information, see Diagnostic cases.
To signal a diagnostic case, the temperature transmitter interrupts the
transfer of temperature measurements and provides these analog outputs
using FOU2:
• ON: 21.5 mA
• OFF: 3.5 mA
Note
In a two-wire operation, the temperature transmitter does not provide
diagnostic messages in the event of low voltage.
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