Gantner IDL 101 - Page 47

IDL 101
FUNCTIONAL DESCRIPTION
HB_IDL101_E_V222.doc
45
Gantner Instruments Test & Measurement GmbH
Determination of the Time Base
The lower the frequency f, the larger is the interval between two impulses, and the larger the time base TB has to be.
On the other hand the updating of the measured value decreases with an increasing time base. Thus the time base
should be selected so as to make
TB ≥ 1/f
u
, f
u
being the lowest frequency or the smallest change in frequency
respectively that still is to be determined by the data logger. The error with frequency measurements thus amounts to
∆ f = f
u
= 1/TB .
Example :
 lowest frequency or frequency change to be measured:
f
u
= 0.1 Hz ⇒ TB ≥ 1/f
u
= 10 s
 lowest frequency or frequency change to be measured:
f
u
= 100 Hz ⇒ ZB ≥ 1/f
u
= 0.1 s
Progressive Counter:
Figure 6.11 Progressive counter
I/O 1
counting
+1 +1 +1 +1 +1
counting
n+1 n+2 n+3 n+4 n+5
signal diagram:
pulse
measurand
When configuring a digital input as a progressive counter the
Datalogger IDL 101 constantly monitors the digital input
for a signal variation. If a negative signal edge (1 -> 0) occurs at the input, the current result is increased by 1.
The range of values of the counter depends on the defined transmission protocol (table 6.2). The values can be reset to
zero via the bus, via the remaining second digital input or via every other variable.
Connection Scheme Circuit
I/O 010 V
I/O 01
+10 .. 30 VDC
0 V
0
V
A
B
R
X
T
X
C
O
M
I
/
O
0
2
I
/
O
0
4
+
1
0
.
.
3
0
V
RS 232RS 485SUPPLY
I
/
O
0
6
I
/
O
0
1
I
/
O
0
3
I
/
O
0
5
INTELLIGENT DATA LOGGER
ADR