ABB PSTX30 Installation And Commissioning Manual page 42

PTC/PT100 input
5.1.2.8
If the motor is equipped with PTC or PT100 elements,
the cables shall be connected to terminals 23 and 24.
See chapter 7 Function settings for programming.
The PTC input uses the same terminals as the
Analogue output and only one of these functions
can be used at the same time.
3-wire measurement for PT100
To minimize the influence of the wire resistance, a
three-wire connection is usually used. By means of the
additional wire, two measuring circuits are created. One
of these two circuits is used for reference. This way, the
tripping device can calculate and take into account the
wire resistance automatically. See Figure 41.
5
Com 3
+(B) -(A)
23 24 25 26 27
Tightening torques and cable dimensions.
2-wire measurement for PT100
When using 2-wire temperature sensors, the sensor
resistance and the wire resistance are added together.
The resulting systematic errors must be taken into
account when adjusting the tripping device. A jumper
must be connected between the terminals T2 and T3.
Table 1 Line length in meter can be used for PT100
sensors to determine the temperature errors caused by
the line length. See Figure 42.
Com 3
+(B) -(A)
23 24 25
Tightening torques and cable dimensions.
Error caused by the line
The error resulting from the line resistance amounts to
approx. 2.5 Kelvin/Ohm. If the resistance of the line is not
known and it is not possible to measure, the error caused
by the line can be estimated using the following table.
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Temp In Analog out
T1 T2 T3 +24V + GND
28 29 30
Temp In Analog out
T1 T2 T3
+24V + GND
26 27 28 29 30
41
PT 100 - 3 wire
Figure 41: PT100 - 3 wire
3,5 x 0,6 mm
M3
(0.138 x 0.024 in)
0,5 Nm
4,3 lb.in
42
PT 100 - 2 wire
Figure 42: PT100 - 2 wire
3,5 x 0,6 mm
M3
(0.138 x 0.024 in)
0,5 Nm
4,3 lb.in
Com 3 Temp In Analog out
+(B) -(A) T1 T2 T3 +24V + GND
23 24 25 26 27 28 29 30
AWG 12 ... 24
2
0,2 .. 2,5 mm
2
2x0,2 .. 1,5 mm
2
0,2 .. 2,5 mm
2
2x0,2 .. 1,5 mm
Com 3 Temp In Analog out
+(B) -(A) T1 T2 T3 +24V + GND
23 24 25 26 27 28 29 30
AWG 12 ... 24
2
0,2 .. 2,5 mm
2
2x0,2 .. 1,5 mm
2
0,2 .. 2,5 mm
2
2x0,2 .. 1,5 mm