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Loop
Powered RTD Transmitter
Model RTT |
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Description:
Model RTT is a 2 wire loop powered
resistive temperature transmitter (RTT) which measures
resistance changes as a function of temperature. It
will convert 2 or 3 wire RTD (Resistive Temperature
Detector) input to a 4 to 20 mA DC current. The output
current is linearized with temperature. It has very
high accuracy, extremely low drift, very low
temperature coefficient, excellent repeatability and
long term stability.
The features of the case include a central hole
for easy spring loading of tube, insulating barriers
between terminals to prevent shorts even under
condensation environment. It can be mounted in a
connection head or a flat surface using the two
mounting holes provided.
Specifications:
Input RTD Type:
Platinum RTD, Pt100, 100 ohm at 0oC, TC
0.00385/ oC.
Input Connection: 3-wire
connection is standard for platinum lead wire
compensation.
Output
Current:
4 to 20 mA.
Accuracy at 23 oC: See
the Table below
Accuracy at 23 oC:
See the Table below.
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Model |
Temperature
Range |
Calibration
Accuracy |
Linearity |
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Single
Range
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RTT-50 |
0 to 50 oC |
0.05% of F.S. |
0.05% of F.S. |
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RTT-100 |
0 to 100 oC |
0.05% of F.S. |
0.05% of F.S. |
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RTT-200 |
0 to 200 oC |
0.05% of F.S. |
0.05% of F.S. |
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RTT-N200 |
-200 to 50 oC |
0.05% of F.S. |
0.05% of F.S. |
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Multi-
Ranges
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RTT-TN50 |
-50 to 50 oC/ -50 to
100 oC / -50
to 150 oC |
0.05% of F.S. |
0.1% of F.S. |
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RTT-T200 |
0 to 50 oC / 0 to
100 oC / 0 to
200 oC |
0.05% of F.S. |
0.1% of F.S. |
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RTT-T500 |
0 to 300 oC/ 0 to
400 oC / 0 to
500 oC |
0.05% of F.S. |
0.1% of F.S. |
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Note: Accuracy not including the error of RTD probe.
Adjustability:
RTD
transmitter is pre-calibrated at factory. Due to the
long-term stability, large range adjustment is not
necessary. Zero and span each are adjustable approx.
+/- 5 % of span.
(Usually when the transmitter has large adjustment
range, the temperature coefficient and drift would be
larger.)
Electrical
Response Time: Under
1 milliseconds.
Common
Mode Rejection: 80
dB typically.
Guaranteed Operating Temperature: -20
to +85 oC
Temperature
Coefficient: Typical
+/- 30 ppm/
oC,
Maximum
+/- 100 ppm/ oC
Storage
Temperature Range:
-40 oC to 100 oC
Relative
Humidity: 0
to 90% RH (non-condensation inside the case)
Power
Requirements at RTT terminals: DC
12.8 V to 26.4V, 1 W.
Maximum
Output Current:
32 mA
Insulating
Resistance between Terminal and Case: >
50 Mohm
Plastic
Case Size:
Dia. 46 mm, Height:
22 mm
Connection:
Terminal blocks.
Weight:
35 gram
Installation:
Case
Dimensions and terminal blocks: See
Fig. 1.
Connection:
Connect
the RTD sensor, wires, current sensing resistor with
volt-meter, or current meter with current limiting
resistor as shown in Fig. 2.
Load
Resistance Selecting Range: In
order to reduce the power dissipation and the drift of
transmitter, the load resistance range is suggested as
follows:
Load Resistance <
[ Supply Voltage (V) – 12.8 V] / 0.02 A
Load Resistance >
[ Supply Voltage (V) – 15 V] / 0.02 A
Calibration: Model RTT is pre-calibrated at the
factory. In case there is a need to recalibrate,
follow the steps below:
- Connect Model RTT as in Fig. 2. Replace RTD
with a precision
decade
resistance box or RTD calibrator.
- Warm-up
for 15 minutes.
- Set
the resistance value to the low end of the
temperature range, and adjust the “Zero”
potentiometer to get 4.000 mA output.
- Increase
the resistance value to full scale and adjust the
“Span” potentiometer for 20.000mA output.
- Repeat
step 3 and step 4 until both levels are accurate,
for there is a very small interaction between the
zero and span control.
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Warranty:
The
RTT series carry a limited warranty of 2 years.
In the event of a failure due to defective
components or workmanship, during the 2 years
warranty, the transmitter will be repaired or replaced
at no charge.
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American Advanced Technologies, Inc. All Rights Reserved.
webmaster@naadvancedtech.com
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