CLIMET INSTRUMENTS CI-154, Руководство пользователя, Страница: 31 / 98

CI-154 User’s Manual
Page 21
The Initial Delay feature is important to allow settling time before the first sample is
taken. The initial delay gives the particle counter time to purge particles from the
sensor and the sample tubing. (Alternatively, the zero count filter can be placed on
the inlet, and the unit can be allowed to run for a period of time to purge the
sensor.) The initial delay is also important when flow alarms are used. Initial delays
of less than 5 seconds may trigger false flow alarms by sampling before the flow
reading has reached its full level. Press the following series of keys, starting from
the main screen, to set up an initial delay of 5 seconds:
[
SET
-
UP
], [
INITIAL DELAY
], [5] (from the numeric keypad), [
EXIT
], [
EXIT
]
2.5.3 Sample delay
The Sample Delay is the delay between samples. There are two types of sample
delays:
 A delay that starts at the end of one sample and ends with the start
of the next sample (End–Start)
 A delay that comprises the time between the start of one sample
and the start of the next sample. In other words, this delay
includes
the sample time (Start–Start).
Normally the sample delay will be set for a period that is less than the actual sample
period. This is fairly straightforward and easy to understand. If, for example, you
want to take four samples with a minimal amount of delay, you might set up the
particle counter to make an
initial delay of 5 seconds, and a sample delay of 0
seconds between samples.
If the delay is set for a period less than the sample time, then it will be an end-to-
start delay. If the delay period is set for a period greater than the sample time, it
will be a start-to-start delay.
For example, if you wanted to take a 1–minute sample automatically every hour,
then you would set the sample delay to 60 minutes. Then the CI-154 will treat the
sample delay as a recurring interval in which it will perform an initial delay of 5
seconds at the start of the first 60-minute interval, take one sample, and then stop
until the end of the delay cycle, at which time it will automatically take a new
sample.
Press the following series of keys, starting from the main screen, to set up a sample
delay of 15 seconds between samples (with the sample period itself being greater
than 15 seconds—the sample must always be greater than the delay):
[
SET
-
UP
], [
SAMPLE DELAY
], [15] (from the numeric keypad), [
EXIT
], [
EXIT
]
2.5.4 Number of samples
The CI-154 can sample continuously, one sample after another, until someone
presses the [
STOP
] key, or it can be set to take a fixed number of samples and then
stop automatically.
To set the CI-154 to take continuous samples, press the [
SET
-
UP
] soft key at the
bottom of the display. When the setup menu appears, locate the [
NUMBER
‘
N
’] key in
the sample group. The box to the right will contain either a number or the letters
INF
. Press the [
NUMBER
‘
N
’] key and then press the [
INF
] key. If the number of
samples box contained a number, the box will contain
INF
when you return to the
set-up menu screen.