ProMinent DulcoFlow DFMa, Руководство по эксплуатации, Страница: 25 / 80

Collector resistance R
C
for frequency signal
lead
The collector resistance R
C
(or pull-up
resistance) and the cable capacity C
K
form an RC member which smooths the
edges of the rectangular pulse. The col‐
lector resistor R
C
for the frequency
signal lead should be selected to be as
low as possible above Rc - dependent
on the maximum frequency and the
requirements on the slope rate for the
monitor being used.
Tab. 4: Maximum cable lengths for various Rc
and fmax
Rc* fmax
Ω 0.5 kHz 1 kHz 10 kHz
100
000
2.5 m 0.7 m -
10 000 30 m 17 0.7 m
1 000 30 m 30 m 17 m
680 30 m 30 m 25.5 m
480 30 m 30 m 30 m
240 30 m 30 m 30 m
180 30 m 30 m 30 m
100 30 m 30 m 30 m
* Minimum value depending on the supply
voltage supplied by your monitor - refer to its
operating instructions and table
Ä
‘Collector
resistance R
C
, minimum level’ on page 24.
The table applies to cable with a specific
capacity of 100 pF/m and in any case
unshielded cable such as type LiYY control
cabling supplied by e.g. Lapp.
Selection of collector resistor Rc
n
Supply voltage of monitor = 30 V
n
Rating for maximum frequency fmax =
10 kHz
1.
Use table
Ä
‘Collector resistance R
C
,
minimum level’ on page 24 to look up
the value for Rc corresponding to 30
V.
ð
This is 680 Ω.
2. Refer to table
Ä
‘NPN connection
information’ on page 20 with the row
for 680 Ω and search for the length
value from the column for fmax = 10
kHz.
ð
This amounts to 25.5 m.
7.3.3 Current output and counter
output
Current output
The device has both a current output (standard
signal output (mA)) and also a counter output.
For a description of these outputs - see
Ä
Chapter 7.3.1 ‘Current output’ on page 18
and
Ä
Chapter 7.3.2 ‘Counter output’
on page 18.
7.3.4 Output for controlled pump
Current output
The device has an output for a controlled
pump. I.e., in conjunction with a delta ® series
metering pump a DulcoFlow ® flow meter can
maintain a constant flow. To do this plug the
cable plug into control module socket. For more
information - see the "Supplementary operating
instructions for the delta ® solenoid metering
pump - control module delta ® ".
Assembly and Installation
25