Functional Software description
DCS 500 Software Description 67
MOTOR_1_PROTECT
ION function block
MOTOR_2_PROTECT
ION function block
Measured Motor
Temperature
The temperature measurement of the motor is usually measured
via analog inputs AI2 and AI3 of the DCS 500B. The temperature
measurement consists of Motor 1: [TEMP IN] (1401) and Motor 2:
[TEMP IN] (1601) channels with alarm and tripping limits. These
channels can be used for temperature supervision of both motors or
of one motor and e.g. the bearings.
If temperature measurement elements are used, the temperature
value can be monitored either in Celsius degrees (PT100) or in
ohms (PTC). It is also possible to use external temperature meas-
urements and therefore give temperature information by means of
current (mA) or voltage to the analog inputs.
Measurement
selection
When the motor temperature is measured using PT100, PTC or
some other type of measuring element, the right type of measuring
must be selected. If the PT100 elements are used, the respective
number is given (1...3). See the parameter AIx CONV MODE (xxx)
in AI2 and AI3 -function block.
When PTC measurement is selected, the conversion result is
scaled as a resistance value.
Also the jumpers of the input voltage range and current generator
must be set correctly in all cases. The SDCS-IOB3-card has only
one current generator; if two temperature measurements are used,
the elements of both channels have to be connected in series.
MOT1.[TEMP IN] (1401) is the input for measured temperature
from motor 1.
MOT2.[TEMP IN] (1601) is the input for measured temperature
from motor 2.
X3:
U
PT100 PT100
5
6
7
8
AI2
X4:
11
AI3
10
5mA
A/D
A/D
SDCS_IOB-3
Figure 47 Two PT100 sensors in a common current source
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