SMY133-SMY134-SMP133 Operating Manual
6.4.1.2 Digital Input as Frequency Counter
6.4.1.2.1 “Frequency” Mode
The frequency counter operation is based on measurement of duration between last two pulses. After
the instrument startup, the quantity value is set to zero until at least two pulses come. Then the
counter value is evaluated periodically each measurement cycle (cca 0,2 s).
6.4.1.2.2 “PWM” Mode
The quantity value is controlled by duty cycle of incoming signal. Evaluation runs as follows :
•
after the instrument startup, the quantity value is undefined for 50 measurement cycles (cca
10 s)
•
then the value is evaluated periodically each measurement cycle (cca 0,2 s)
•
if the duty cycle drops below 0,5%, it is rounded to 0%; if it exceeds 99,5% it is rounded to
100%
6.4.1.3 Digital Input as Pulse Counter
The pulse counters have capacity of 2
32
– 1pulses. Then overflow occurs and the counter starts to
count from zero again. Contents of the counters is maintained in case of power failure.
Actual state of the counters can be checked via a communication link only using the ENVIS-Daq
program.
6.4.2 Digital Outputs
Digital outputs are processed and refreshed after each measurement cycle, i.e. usually every 200 ms.
The only exclusion are the outputs set to
pulse function
.
6.4.2.1 Pulse Outputs
After the pulse function mode is set, every 200 milliseconds the instrument executes evaluation of the
measured electric energy. If the increment of recorded electric power is higher or equal to the quantity
of power per one pulse, the instrument will transmit one or two pulses. The mentioned description
shows that the fluency of pulse transmission is +/- 200 ms.
The pulse width and minimum pulse gap are 50 / 50 ms (compliant with so-called S0-output
definition), maximum frequency is 10 pulses per second.
57
