TT-40
Tempe ratur e Trans mitter
Se ries 40
Features and Benefits
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Two wire 4 - 20mA loop.
Fits in a standard ANSI or DIN head.
Low cost and easy to installation.
Saves on costs of the compensating cable in thermocouple
installation.
Auto cold junction compensation.
Excellent RF immunity.
ORDERING CODE
Description of Operation
The Series 40 temperature transmitters are designed to fit
into standard (ANSI or DIN) weatherproof heads. RTD or
thermocouple assemblies provide a 4-20mA transmission
signal. The use of these transmitters reduces the
possibility of induced EMC in cables, and also eliminates
the high cost of compensating cable in thermocouple
installation.
The transmitters may be ordered for any type of
thermocouple and for any temperature range with a
minimum span of 4mV.
PT100 sensor with linearised output.
In both RTD and thermocouple models the units are
provided with MOV protection against surges produced in
transmission lines, as well as stray voltages which may be
picked up by measuring elements. Care has also be taken
in the design to minimise interference from RF
transmission. An LED illuminates to indicate when the
transmitter is powered and operational.
When used with a thermocouple input the unit incorporates
an automatic cold junction compensation circuit. Two
versions are available. The first has an output signal
proportional to the millivolt input, and the second has an
output signal proportional to temperature.
For resistance input the unit is designed to accept 3 wire
Dimensional Diagram
43
32
24 (Max height)
20
Dimensions in mm
3
+
4-20mA
SPAN
_
ZERO
_
+ Type
K
5
1. Positive output: 4-20mA Linear to input.
2. Negative output:
3. Span adjustment: To adjust to 20mA.
4. Zero adjustment: To adjust the 4mA.
5. Input from temperature sensor: Polarity sensitive on thermocouple
inputs.
2
4
5
PT100
1
3
+
4-20mA
SPAN
Pt100
5
_
2
ZERO
4
5
Wiring and Connection
A 4-20mA loop is typically powered by a 24V DC power
supply. A temperature transmitter is basically a current
sink which pulls current from the power supply.
means that 12 volts is left for the rest of the loop. Using
Ohms Law this means that all the other units in the same
loop must have a total impedance of less than 600
ohms.
For most transmitters a stabilised supply is not required
as they are true voltage to current converters, however
there is usually a small error introduced by changes in
voltage.
If the impedance of the instruments is greater than 600
ohms (and this may be the case in Intrinsically Safe
circuits where zener barrier are used), then problems
arise.
To function correctly a typical transmitter requires a
minimum of 12 volts across its supply terminals. This
9 10 11 12 13 14 15 16
+24Volt
Excitation
2
1
Latch
Relay
Relay
Retransmission
1 2 3 4 5
Digital Indicator with
24 Volt excitation and
retransmission.
Supply
6 7 8
L or +
N or -
Output
Common
Signal
-24Volt
Input
Common
Input
Signal
4-20mA Instrument
Internal
Shunt
Resistor
Supply Input
-
Thermocouple
+
Temperature
Transmitter
For more info: www.rhomberg.co.za
TT LINE
1
Description of Controls
T E M P E R AT U R E
Thermocouple
TRANSMITTER
Precision Measures Perfection
HOW TO ORDER
TT-Line
TT-LINE Ordering Code
TT
40
1
LG
T
P
C
J0150
TEMP RANGE
UNIT
TYPE
OUTPUT
CASE
OPTION
ITEM
TYPE
Code
J0150
J0200
J0600
K0100
K0150
K0200
K0300
K0600
K1000
K1200
P0050
P0100
P0200
P0300
P0400
P1050
P5050
Range
0 to 150, J Type, Thermocouple
0 to 200, J Type, Thermocouple
0 to 600, J Type, Thermocouple
0 to 100, K Type, Thermocouple
0 to 150, K Type, Thermocouple
0 to 200, K Type, Thermocouple
0 to 300, K Type, Thermocouple
0 to 600, K Type, Thermocouple
0 to 1000, K Type, Thermocouple
0 to 1200, K Type, Thermocouple
0 to 50, PT100, RTD Input
0 to 100, PT100, RTD Input
0 to 200, PT100, RTD Input
0 to 300, PT100, RTD Input
0 to 400, PT100, RTD Input
-10 to 50, PT100, RTD Input
-50 to 50, PT100, RTD Input
Code
Unit
C
F
°C
°F
Code
Type
J
K
T
P
Type J
Type K
Type T
PT100
Code
Output
T
M
R
Linear to Temp
Linear to mV
Not Applicable
Code
LG
Case
LG Head
Code
Option
0
1
Thermocouple
RTD 3 Wire
Code
40
Item
4 - 20mA
Temperature Transmitter