Sample Every; Flow Pulse Intervals At Various Input Currents - Teledyne 5800 Installation And Operation Manual

Isco 5800 Refrigerated Sampler
Section 3 Programming

3.5.3 Sample Every

__ Hours, __ Minutes
3.5.4 Sample Every
__ Pulses
3-16
Use the Next or Previous arrows to select the time or flow option,
then press the Enter button.
Time Paced Only. Use the Number buttons to enter the time
interval in hours and minutes. The sampler collects a sample
each time this interval elapses while the program is running.
Flow Paced Only. Use the Number buttons to enter the flow
interval as a number of pulses. While the program is running the
sampler counts the flow pulses until this number is reached. At
this time the sampler collects a sample and resets the interval to
begin counting again.
The volume that each flow pulse represents is determined by the
flow measurement device. With some instruments this volume is
user-defined; others use a fixed volume. Refer to the instruction
manual of the flow measurement device.
For example, consider an Isco 4250 Flow Meter programmed to
send a flow pulse every 100 gallons. If you are required to collect
a sample every 10,000 gallons, you would enter 100 flow pulses.
10000 gallons
If the flow measurement device sends flow rate data via a
4-20 mA current loop instead of flow pulses, the sampler converts
this analog current to flow pulses representative of a volume.
The sampler assumes that the current is linear from 4 mA at
z e r o f l o w t o 2 0 m A a t t h e f u l l - s c a l e f l o w r a t e . T h i s
factory-calibrated conversion produces one pulse every 12
seconds (5 flow pulses per minute) at 20 mA and scales the pulse
intervals until there are no pulses at 4 mA. See Table 3-2 for flow
pulse intervals at various currents.
Table 3-2 Flow Pulse Intervals at Various
Input
Current (mA)
4
5
6
7
8
9
10
11
12
13
14

100 gallons per pulse 100 pulses
=
Input Currents
Seconds Between
Pulses
 (no pulses)
192
96
64
48
38.4
32
27.4
24
21.3
19.2
% of Full Scale
Flow Rate
0
6.25
12.5
18.75
25
31.25
37.5
43.75
50
56.25
62.5