Gantner IDL 101 - Page 46

IDL 101
FUNCTIONAL DESCRIPTION
44 HB_IDL101_E_V222.doc
Gantner Instruments Test & Measurement GmbH
Frequency Measurement:
I
/
O
1
0
V
I
/
O
2
0
V
I
/
O
3
0
V
I
/
O
4
0
V
I
/
O
5
0
V
I
/
O
6
0
V
Connection Scheme
I/O 1
0 V
Circuit
+10 .. 30 VDC
f
I/O 1
0 V
f
D I G I T A L
INTELLIGENT DATA LOGGER
IDL
100
Figure 6.10 Frequency measurement
I/O 1
Time Base
ZB ZB ZB
Counting
1231231231
Measurand
(TB = 5 sec)
Signal Diagram:
0,6 Hz 0,6 Hz 0,6 Hz
Pulse
With frequency measurements the data logger counts the pulses occurring in a particular time interval at the digital
input. The user can preset this time interval by signalizing the time base (TB) in the range between 0.1 sec and 10 sec.
The frequency is calculated by the sensor module from the number of impulses and the time base
TB as:
frequency f =
number of impulses per time interval TB
length of time intervall TB
Hz
With frequency measurements it is always the negative signal edge (1 -> 0) that is counted at the digital signal input.
Notice : The high-end frequency is 2000 Hz.
Notice: Frequency measurements can only be performed at the digital inputs I/O 01 to I/O 06 at 2000 Hz. As soon as
more than 6 frequency measurements have to be realized, the high-end frequency is 100Hz.