Fail-Safe signal module (SM) diagnostics
6.2 Fault diagnostics
S7-1200 Functional Safety Manual
Manual, 02/2015, A5E03470344-AA
129
SM 1226 F-DQ
2 x Relay
Relay state does not
agree with com-
Relay faulty Replace the fail-safe SM.
0x0320 Overload SM 1226 F-DQ
4 x 24 VDC
Over load condition
at the output driver
that leads to pas-
sivation of the chan-
Over load at output Eliminate over load.
0x0321 Supply voltage
All Supply voltage max-
Supply voltage is set
Adjust supply voltage.
0x0322 Supply voltage
All Supply voltage mini-
Supply voltage is set
Adjust supply voltage.
0x032C Failsafe error
(0x032C)
SM 1226 F-DQ
2 x Relay
Maximum relay
switch on time ex-
ceeded.
Safety program did
not switch the relay
within the configured
"Relay continuous
on time limit".
• Include in the safety
program and process
operations an oppor-
tunity to turn the relay
"OFF" briefly, to allow
the module to confirm
that the relay is still un-
der control.
• Increase the "Relay
continuous on time lim-
it'. This value cannot
exceed 30 days for SIL
3 applications.
Once the fault is eliminated, the fail-safe signal module must be reintegrated (returned to normal state) from passivation
Electromagnetic interference and diagnostic reports
Electromagnetic interference can cause communication errors, disturb external and internal
signal measurements, and cause processing errors. When error reports do not apparently
relate to an identifiable device failure, wiring problem, programming or configuration error,
consider sources of electromagnetic interference and installation and wiring problems that
might introduce electromagnetic interference in your installation. Typical problem sources
include poor suppression of inductive loads and voltage dips due to excessive load in-rush
currents.
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