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Siemens
TX-I/O™ Module system – Functions and operation
CM110561en_08
Building Technologies
Digital input functions
2018-10-25
3.2 Status indication, pulse contact
(BI Pulse NO / D20S)
(Function for
P-bus BIM
: See section 3.3)
Used for the acquisition of
status pulses
from volt-free pulse contacts and electronic
pulse transmitters such as transistors and optocouplers.
The pulses can be triggered by:
– Mains voltage monitoring systems
– Emergency pushbutton signals, e.g. in elevators
– Start-up monitoring for analysis of faults
•
The function requires one I/O point
LCD
Signal Processing
(D20S)
Memory
Process
value
Acknowledge
I/O status LED
NO Contact
BUS
BUS
10
56
1z
15
6
Block diagram of function
•
The signal is read and debounced on hardware level
•
An additional debounce time is available: 0…25.5 s (default = 0 s)
•
The pulse is then saved and transmitted to the bus master
•
The bus master acknowledges receipt (Acknowledge)
•
The memory is cleared, the LED goes off, and the input is ready for a new pulse
Additional incoming pulses before the Acknowledge are ignored.
•
The signal operation can be selected: Contact_NO (default), Contact_NC)
Digital inputs cannot be overridden locally. The override button has no effect, and if an
attempt is made to operate it, an error is displayed.
•
The
I/O status LED
does not show the source signal, but the state of the
signal
memory
•
The
LCD panel
(if available) shows the
source signal type
(status contact, N/O or
N/C contact)
•
The LCD panel
shows the
change
(a block of 3 fields which change with each pulse):
Application
Hardware
Function
Local override
Display