ONLINE ELECTRONICS LTD
ID5000A_5001_A03
Page 9 of 21
3.3.11.
SET DETECT COUNT
Accessed from SETUP MODE 1. DETECT COUNT controls how easy or hard it is for the unit to
be triggered. It is available as a setting to allow the unit to discriminate between a pig passage
and a spurious loss of signal caused by for example gas bubbles passing the transducer. The
unit transmits 100 pulses through the pipe every second. If DETECT COUNT is set to 01 then if
one of these pulses does not get reflected back then a pig passage is assumed. If DETECT
COUNT is set to 255 then 255 consecutive pulses would have to be missed before a pig
passage is assumed, meaning the signal was removed for 2.55 seconds. The table below
shows recommended values for a range of pipe sizes assuming a
spherical
pig (i.e. worst
case) with speed of 10 metres per second or 1 metre per second. See section 3.6 DETECTION
ALGORITHM for more information.
PIPE DIAMETER
DETECT COUNT
(PIG SPEED 10m/s)
DETECT COUNT
(PIG SPEED 1m/s)
6” (15.24cm)
1
15
12” (
30.48cm)
3
30
24” (60.96cm)
6
60
36” (91.44cm)
9
90
48” (121.92cm)
12
120
3.3.12.
SET INDICATOR DELAY
Accessed from SETUP MODE 1. This parameter determines how long the unit will signal a PIG
DETECTION for. See section 3.2 DETECTION MODE 0.
The INDICATOR DELAY can be set between 00:00:00 and 99:99:99 in HH:MM:SS format. Note
that the time entered will be the time that the LEDs will flash every second for. The
seconds
field will be the total number of seconds which the display shall show the pig detection time
and date for. E.g. if INDICATOR DELAY is set to 01:59:60 the unit will flash every second for 2
hours and for the first 60 seconds of this time it will show the pig passage time and date on
the display.
3.3.13.
SET MINIMUM DIAMETER
Accessed from SETUP MODE 1. The MINIMUM DIAMETER value determines how long the unit
shall wait for after it transmits a pulse before it looks for a reflection. Basically it allows the
user to force the unit to ignore any spurious signals which take place between the transmit
pulse and the reflected signal.
The first signal received after the MINIMUM DIAMETER value which has amplitude greater than
the threshold level shall be measured and if it is within 2cm of
the pipe diameter a ‘good’
reflection will be assumed. Normally a minimum echo value which is approximately 33% of the
pipeline diameter will be sufficient. E.g. is pipe is 30cm diameter then a value of 10cm for
MINIMUM DIAMETER will suffice.
If the transmit pulse is not dying away quick enough or there are significant spurious echoes
present then choosing a larger MINIMUM DIAMETER value may be required but it should never
be set within 6cm of the actual pipe diameter.
3.3.14.
SET TIME
Accessed from SETUP MODE 1. This option allows the user to set the internal system time.
3.3.15.
SET DATE
Accessed from SETUP MODE 1. This option allows the user to set the internal system date.