5.1.2.8 PTC/PT100 input
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.
0,2 .. 2,5 mm
2
2x0,2 .. 1,5 mm
2
0,2 .. 2,5 mm
2
2x0,2 .. 1,5 mm
2
AWG 12 ... 24
0,5 Nm
4,3 lb.in
3,5 x 0,6 mm
(0.138 x 0.024 in)
M3
23 24 25 26 27
T1 T2 T3
28 29 30
+(B) -(A) +24V +GND
Analog outTemp InCom 3
1SFC132081M0201
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.
0,2 .. 2,5 mm
2
2x0,2 .. 1,5 mm
2
0,2 .. 2,5 mm
2
2x0,2 .. 1,5 mm
2
AWG 12 ... 24
0,5 Nm
4,3 lb.in
3,5 x 0,6 mm
(0.138 x 0.024 in)
M3
23 24 25 26 27
T1 T2 T3
28 29 30
+(B) -(A) +24V +GND
Analog outTemp InCom 3
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.
41
PT 100 - 3 wire
23 24 25 26 27
T1 T2 T3
28 29 30
+(B) -(A) +24V +GND
Analog outTemp InCom 3
1SFC132081M0201
Figure 41: PT100 - 3 wire
42
PT 100 - 2 wire
23 24 25 26 27
T1 T2 T3
28 29 30
+(B) -(A) +24V +GND
Analog outTemp InCom 3
1SFC132081M0201
Figure 42: PT100 - 2 wire
5
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