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3 CNT EXPANSION PORT
3.1
Description
The user interface CNT is for monitoring and processing analogue and binary signals and for control-
ling (settings) of binary signals. There are 2 counter and 2 binary inputs or 4 binary inputs, 2 ana-
logue inputs and 1 binary output available. The settings of binaries and counter inputs by the help of
firmware in which the single input and output is defined. Binary output is off by default configura-
tion (is not switched to ground).
At expansion port CNT including in modem, it is possible to use power supply management. At per-
manent idleness the expansion port CNT is switch to low power supply mode when demand current
is very low (100 μA). Switch time to this status is program adjustable. The module wake up is possi-
ble by PORT status variation.
3.2
Input and output description
3.2.1
Analog input
On analogy input it detected current, converted to digital 12-bits value and modified by multiplica-
tive and additive constant. Next the value is averaged on user settings and stored to PC memory.
The basic range of input current is 0 – 20 mA at input resistance 100 Ohm.
Equal of value is:
((12b value + addit. constant) * multiplic. constant)/1000
The sample period on analogy inputs is adjustable in range 0 ÷ 65535 seconds. At value 0 it is sam-
pling once per second and measurement circuit is permanent switch on. At sampling it is possible to
set time of measurement circuit switch from 16 ms to 375 ms.
On the basis of signal change about bigger value then setting upper/lower limit is generated alarm.
The alarm end is on the basis of bigger/lower signal change about set hysteresis than is upper/lower
limit.
3.2.2
Binary input
The binary input is potential-free contact which is 8x per second sampling and sampling time is
1/64 seconds. For binary inputs it is possible to set active level to either log. 0 or log. 1. Choosing ac-
tive level can generate an alarm.
3.2.3
Counter input
The counter inputs are meters maximal to 100 Hz. The ratio impulses on input can be maximal 1:10,
that means the impulse width must not be lower than 1/10 signal period. At lower width the true
evaluation of the metered signal is not guaranteed. For metering of small frequencies (about MHz) it
is important to set the multiplicative constant which multiplies metering frequency (flow) because
of true evaluation.
On the basis of signal change about bigger value then setting frequency upper limit is generated
alarm. Alarm is possible send after time after which upper limit must be overrun.
In case that it isn't any change on input, it is possible to define time after which the value on input
will zero.
Wieland Electric GmbH | BA000917 | 08/2021 (Rev. C)
CNT expansion port
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