Temperature Sensor Input Broken Wire Detection - Panasonic FP2 -C1A Manual

FP2 Analog Unit
8.4

Temperature Sensor Input Broken Wire Detection

For the input channels of the thermocouple input range and R.T.D (resistance
thermometer device) input range, you can detect broken wires in the input wiring for each
channel.
For the detection of the broken wires, there are two methods of detection: one is
detection performed by the broken - wire detection flags in shared memory, and the other
is detection by the temperature sensor input conversion data (the conversion data is
K20000).
Program example:
When the reading conditions for the analog input ch0 conversion data is to use the
broken - wire detection flag and read to DT0.
R9010
F150 READ, K 0 , K 42 , K 1 , WR 0
Initial setting
When the analog input
unit is installed at slot 0
R0
ch0 reading
Precautions when using broken wire detection for the resistance thermometer
device input wiring
For broken wire detection in the FP2 three - wire resistance thermometer device input
wiring, depending on which wire breaks as shown below, there are situations where the
broken wire detection cannot be performed.
Wire (1) is broken: Broken wire detection is possible
Only (2) wire is broken: Broken wire detection is not possible
Only (3) wire is broken: Broken wire detection is not possible
Wires (2) and (3) are broken: Broken wire detection is possible
Three- wire R.T.D (Resistance thermometer device)
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From shared memory address 42
F0 MV , WX 0
(1)
V n
(2)
COM
(3)
I n
Sample Program for Analog Input
8.4 Temperature Sensor Input Broken Wire Detection
To WR0
, DT 0
Ch n
Input terminals
8 - 9