3.17
Metering frequencies
3.17.1
Properties
Properties
The electronic module 8 DI NAMUR allows the frequencies to be measured on channel 0 and
1:
● 2 frequency meters from 1 Hz to 5 kHz
● Configurable metering window (GATE)
● The signals of the frequency meter are read in by means of the digital inputs of the electronic
module.
● You configure the counters of the 8 DI NAMUR electronic module and assign the
parameters in the configuration software, for example, HW Config.
● Configuration "2 Trace/ 6DI NAMUR": This configuration makes available 2 frequency
meters.
3.17.2
Principle of operation
Frequency measurement
The signal frequencies are identified from the input signals of channel 0 or 1 of the electronic
module. To calculate the frequency the signals are measured within a configurable gate.
The frequency is displayed as 16-bit value in fixed-point format and transferred to the PII.
The frequency meter calculates the frequency according to the follow formula:
)UHTXHQF\>+]@
1XPEHURIULVLQJHGJHVDWGLJLWDOLQSXW
0HDVXULQJZLQGRZ>V@
Exceeding the input frequency
If the input frequency exceeds 5kHz, 7FFF
H
is reported as actual value. If the input frequency
is above approx. 8 kHz it is no longer possible to display correct actual values.
Configuration options
3.17 Metering frequencies
ET 200iSP
76
Operating Instructions, 11/2017, A5E00247483-07