Siemens SIMATIC ET 200AL System Manual page 442

5.2 Interrupts
The DIQ 4+DQ 4x24VDC/0.5A 8xM8 digital input/digital output module supports diagnostic
interrupts.
Diagnostic interrupt
The digital input/digital output module generates a diagnostic interrupt at the following
events:
• Short-circuit of encoder supply to ground
• Short-circuit of outputs to ground
• Load voltage 2L+ missing or too low
5.3 Diagnostics alarms
For each diagnostic event, a diagnostics alarm is issued and the DIAG LED flashes red on the
digital input/output module.
You can read out the diagnostics alarms, for example, from the diagnostics buffer of the CPU.
You can evaluate the error codes with the user program.
Table 5- 4
Diagnostics alarm Error code
Short-circuit*
Load voltage 2L+
missing**
* If a short-circuit of the encoder supply to ground is detected, the diagnostic alarm "Short-circuit" is
always output. This alarm is output even if all channels are configured as outputs.
** If you are using ET 200AL modules in connection with the ET 200SP distributed I/O system, the
diagnostic alarm "Load voltage missing" is displayed.
Note
Channel type
The digital input/digital output module is always signaled as a mixed module (channel type
"Input/Output") in the case of diagnostic events, even if you have configured the digital
input/digital output module exclusively as an output module.
Digital input/digital output module DIQ 4+DQ 4x24VDC/0.5A 8xM8 (6ES7143-5BF00-0BA0)
Equipment Manual, 08/2021, A5E32349882-AD
Diagnostics alarms, their meanings and corrective measures
Meaning
1 Short-circuit encoder supply to
H
ground
Short-circuit of outputs to
ground
11 Load voltage 2L+ missing or too
H
low
Interrupts/diagnostics alarms
5.2 Interrupts
Remedy
• Eliminate the short-circuit
• Check the supply voltage
• Check the module
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