2
Description
Model TT273 is a 2-wire temperature transmitter for RTD (resistance temperature detector) thermometers. The
Temptran
TM
converts the RTD's signal into a 4 to 20 mA current. The current changes according to the range
marked on the Temptran: 4 mA at the lowest temperature of the range, rising to 20 mA at the top of the range.
The leads that supply power also carry the current signal. Request Minco Application Aid 15 for more
information.
Installation
Locate the Temptran near the RTD, in an area where the ambient temperature stays between -40 and 85
°
C (-40
and 185
°
F). If calibration will be necessary, set dip-switches before attaching unit to the DIN rail.
Connect the Temptran as shown below, observing the
±
polarity of the current loop. Maximum DC supply
voltage = 45 VDC. The RTD connections for the Temptran in the wiring diagram below must be connected as
shown or the transmitter will not function properly.
Wiring Diagram
Calibration
1.
Select desired Zero (4 mA temp.) temperature and Span (20 mA temp. - 4 mA temp.) range from the tables
below. The Zero temperature must be within -50 to 150 °C, and the Span range must be within 50 to 600
°C. For example, for a -25 to 200 °C temperature range, the Zero temperature is -25 °C and the Span
range is (200-(-25)) = 225 °C. According to the tables, switch positions 1 and 8 would be ON.
2.
Set dip-switches per values selected from tables.
4.
Connect a power supply of 24 VDC, and a digital milliammeter (5-1/2 digit preferred) as shown in figure 1,
or use a loop calibrator instead of the DC supply and milliammeter.
Zero (4 mA) coarse adjust
Switch Position
Zero Range / Ohm Setting
1 ON
2,3 OFF
-50 to 0
°
C (-58 to 32 °F)
80.306
Ω
to 100.000
Ω
2 ON
1,3 OFF
0 to 50
°
C (32 to 122 °F)
100.000
Ω
to 119.397
Ω
3 ON
1,2 OFF
50 to 100
°
C (122 to 212 °F)
119.397
Ω
to 138.506
Ω
1,2,3 OFF
100 to 150
°
C (212 to 302 °F)
135.506
Ω
to 157.025
Ω
Span (20 mA - 4 mA) coarse adjust
Switch Position
Span Range / Ohm Setting
4 ON
5-9 OFF
50 to 70
°
C (90 to 126 °F)
119.397
Ω
to 127.075
Ω
5 ON
4,6-9 OFF
70 to 100
°
C (126 to 180 °F)
127.075
Ω
to 138.506
Ω
6 ON
4,5,7-9 OFF
100 to 140
°
C (180 to 252 °F)
138.506
Ω
to 153.584
Ω
7 ON
4-6,8,9 ON
140 to 200
°
C (252 to 360 °F)
153.584
Ω
to 175.856
Ω
8 ON
4-7,9 OFF
200 to 300
°
C (360 to 540 °F)
175.856
Ω
to 212.052
Ω
9 ON
4-8 OFF
300 to 425
°
C (540 to 765 °F)
212.052
Ω
to 255.672
Ω
4-9 OFF
425 to 600
°
C (765 to 1080 °F)
255.672
Ω
to 313.708
Ω