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Siemens
TX-I/O™ Module system – Functions and operation
CM110561en_08
Building Technologies
Digital input functions
2018-10-25
3.6 Counting, pulse contact
(CI Mech (10/25 Hz), CI El (100Hz) / C)
Acquisition of
counter pulses
from
– Heat meters
– Flow meters
– Electricity meters
In conjunction with energy metering, the counter function can also be used for the
acquisition of synchronization pulses, which may
– trigger the start of a new measuring period, or
– initiate a switching event (change of tariff, load-shedding).
The function requires one I/O point.
I/O status LED
Memory
LCD
Process value
Contact
BUS
10
56
1Z
10
5
Block diagram of function
•
The signal is debounced on hardware level and registered
•
The function reacts on the closing edge of the signal, registers the counter pulses
and accumulates them in the memory.
•
You can choose a mechnical or an electric counter under
Pulse Generator
:
– mechanic contact
⇒
Counting frequency up to 25 Hz
– electric contact
⇒
Counting frequency up to 100 Hz
•
Certain module types support lower frequencies, see module data sheets and the
overview in section 1.7.
•
The value stored in memory is available in the process value
–
P-bus BIM
: The P-bus is limited to 64 units (6 bits). This means that for counting
at 25 Hz the cycle time of the automation station must be set to
≤
2 s.
– The memory has a maximum value of (2
32
)–1 (
≈
4.3 x 10
9
).
•
The value of the memory can be deleted, or set via one of the parameters
AddCorrValue,
SubCorrValue
or
NewCIValue
(2
32
)–1
•
The behavior of the counter at
Power-Up
can be set as follows (only in the I/O
Address Editor):
–
Reset
–
Last value
(last value from buffer)
•
COV Limit
and
COV Period
define the amount of change and the interval for updates
to be sent on the island bus by the module.
Application
Hardware
Function