Siemens SIMATIC S7-1500 Manual page 46

Interrupts/diagnostic alarms
5.1 Status and error displays
Channel LEDs
The CHn.P/A, CHn.D/B, and DIn.m LEDs and the LEDs of DIQn.2 used as digital inputs
indicate the current level of the associated signals. The LEDs of digital outputs DQn.m and
of DIQn.2 used as digital outputs indicate the desired state.
The flashing frequency of the channel LEDs is limited to approximately 24 Hz. If higher
frequencies are present, the channel LEDs do not indicate the current status but instead
flash at 24 Hz.
Table 5- 3
CHn.m/DIn.m/
DQn.m/DIQn.2
(DQn.m/DIQn.2)
46
Status displays CHn.m/DIn.m/DQn.m/DIQn.2
LEDs
Pulse output/digital input/digital output
at 0 level
Off
Pulse output/digital input/digital output
at 1 level
On
Diagnostic alarm:
e.g. "Error at digital outputs"
On
Meaning
Technology Module TM PTO 4 (6ES7553-1AA00-0AB0)
To correct or avoid errors
—
—
Evaluate the diagnostic alarm.
•
Check the wiring or the connected
•
load.
Manual, 12/2016, A5E38896703-AA