Specifications

Interrupts/diagnostics alarms
5.1 Status and error displays
DI 32x24VDC HF digital input module (6ES7521-1BL00-0AB0)
Manual, 04/2015, A5E03485935-AE
37
RUN and ERROR LED
Table 5- 1 Status and error displays RUN and ERROR
LED
Meaning
Remedy
RUN
ERROR
Off Off
Voltage missing or too low at backplane bus
• Switch on the CPU and/or the system
power supply modules.
• Verify that the U connectors are inserted.
• Check to see if too many modules are
inserted.
Flashes
Off
The module starts and flashes until the valid
parameter assignment is set.
---
On Off
Module is configured
On
Flashes
Indicates module errors (at least one error at
one channel, e.g., wire break).
Evaluate the diagnostics data and eliminate the
error (e.g., wire break).
Flashes
Flashes
Hardware defective Replace the module.
PWR1 and PWR2 LED
Table 5- 2 PWR1 and PWR2 status indication
LED PWR1 / PWR2
Meaning
Remedy
Off
Supply voltage L+ too low or missing Check supply voltage L+.
On
Supply voltage L+ is present and OK ---
CHx LED
Table 5- 3 CHx status display
LED CHx
Meaning
Remedy
Off
0 = Status of the input signal ---
On
1 = Status of the input signal ---
On
Diagnostics: Wire break Check the wiring. When using simple switches,
deactivate diagnostics or connect a resistor
(25 kΩ … 45 kΩ) to the encoder contacts.
Supply voltage L+ too low or missing
Check supply voltage L+