Operating Instructions

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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
10561Z105
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