II - DCE FEL ČVUT v Praze

Input delay
Diagnostics
Parameterizing
diagnostics
Diagnostic
evaluation
I/O Modules with Intrinsically-Safe Signals
C79000-G7076-C152-04
Table 2-4 shows the possible configurable input delay times for SM 321;
DI 4 x NAMUR and their tolerances.
Table 2-4 Delay times of input signal for SM 321; DI 4 x NAMUR
Input delay Tolerance
0.1 ms 75 to 150 s
0.5 ms 0.4 to 0.8 ms
3 ms (default) 2.8 to 3.5 ms
15 ms 14.5 to 15.5 ms
20 ms 19 to 21 ms
You can use the diagnostic function to determine whether signal acquisition
takes place without errors.
Diagnostics is parameterized with STEP 7.
SIMATIC S7 Ex Digital Modules
When evaluating the diagnostics, a differentiation must be made between
configurable and non-configurable diagnostic messages. In the case of the
configurable diagnostic message ”wire break” or ”short to M”, diagnostics is
only signalled when diagnostic evaluation has been enabled by means of
parameterization (parameter ”wire break” or ”short to M”).
Non-configurable diagnostic messages are general, i.e. independent of
parameterization.
A diagnostic signal results in a diagnostic interrupt being triggered providing
the diagnostic interrupt has been enabled by way of parameterization.
Irrespective of the parameterization, known module errors always result in
the SF LED and the corresponding channel fault LED lighting irrespective of
the CPU operating status (at POWER ON).
Exception: The SF LED and the corresponding channel fault LED light in
the event of a wire break only when parameterization is enabled.
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