Siemens SIMATIC ET 200SP - Page 59

Supplements to ET 200SP documentation
2.5 I/O module manuals
Product information on the documentation of the ET 200SP distributed I/O system
Product Information, 02/2021, A5E03799595-BG
59
Table 2- 9 Measured values in case of a line break in a TC measurement with enabled reference junction (reference chan-
nel) depending on enabled diagnostic information
Case
Programmable diagnostics
Measured value
Reference channel
TC channel
Reference channel TC channel
Wire break
Underflow
Wire break
Underflow
1
Enable
3
*
3
*
*
2
32767
3
7FFFH
3
32767
4
7FFFH
4
2
Disable
3
*
3
*
*
2
32767
3
7FFFH
3
32767
4
7FFFH
4
3
*
*
Enable
3
*
3
Valid
Valid
32767
3
7FFFH
3
4
*
*
Disable
3
*
3
Valid
Valid
32767
3
7FFFH
3
5
*
*
Disable
1.3 *3
Valid
Valid
Undefined
* Parameter assignment not relevant
1
The wire break test can only be disabled via data set 237.
2
Diagnostics is suppressed in the event of a reference channel error.
3
Channel with line break
4
Measured value taken from the reference channel
Explanations of the cases:
Case
Reference channel
TC channel
1
The "wire break" diagnostics is reported.
This has a higher priority than the "Underflow" diagnos-
tics.*
The "Reference channel error" diagnostics is reported if
this is enabled. Where own pending diagnostic infor-
mation ("overflow" or "underflow") is reported as out-
going. Wire break diagnostics is detected independently
of the measured value and has the same priority as the
"Reference channel error" diagnostics. Both items of diag-
nostic information can be pending simultaneously. The
measured value of the reference channel (RTD channel) is
adopted for the TC channel. The validity of the measured
value of the TC channel is irrelevant.
2
No diagnostics reported. A wire break check is carried
out (i.e. test current flows).*
Behavior corresponds to case 1.
3
Measured values are in the valid measuring range
The "wire break" diagnostics is reported.*
4
Measured values are in the valid measuring range
No diagnostics reported. A wire break check is carried out
(i.e. test current flows).*
5
Measured values are in the valid measuring range
No "wire break" diagnostics is reported. No wire break
check is carried out (i.e. no test current flows). This is
required to calibrate thermocouples, since the test current
necessary for a wire break check leads to measurement
errors during calibration.*
* Channel with wire break