9.3.12
Broken Wire Signal
Broken wire signal in the
standard Pt 100 range
An open-circuit in the lines to a resistance thermometer is indicated as
follows:
Broken Wire at
Module Reaction, Encoded
Value
Error Bit E
M+
M-
Pt 100
I
C+
I
C-
0
0
0
1)
0
0
1
1
1
0
0
1)
With the 460 analog input module, the value 0 is also encoded for the
intact Pt 100 resistances because the auxiliary circuit is interrupted; the
error bit will not be set for these channels.
If the mode "without broken wire signal" is selected on the module, an
open-circuit of the resistance thermometer is indicated with an
overflow.
Unassigned channels can be used for voltage or current measurement.
Broken wire signal in the
extended Pt 100 range
If a line of the auxiliary circuit (I
C+
, I
C-
) is interrupted, the "negative
range limit" is encoded for all inputs and the overflow bit is set to "1".
In the event of a sensor or measuring line open-circuit, the error bit is
additionally set to "1" for the relevant channel.
The 460 Analog Input Module
System Manual
9 - 24
C79000-B8576-C109-03
