P
AGE
10
OF
25
7.
Fill Timer Blocks in the Venturi Sampler PLC.
Block No. Block Description
Default Value
Unit
B106
Timers used to control the purge sequence for up to 4 or 6
optional stream valves, for 4 and 6 stream venturi sampler
option.
ON: 40
OFF: 1
ms
B126
161 / 241
ms
B147
16 / 24
s
B148
Purge chamber and line prior to filling timer.
20
s
Note: Some applications may have a certain size particulate separation chamber
“External Chamber”
option which gathers and settles the sample at the sampling point prior to the Venturi Sampler is filled
with the sample. In applications where this chamber is present, B170 & B172 are changed from the
default zero second value to the site specific values.
B170
External chamber fill time.
0
s
B172
External chamber settling time.
0
s
B155
This block serves two purposes:
1. There are liquid sensors to stop the Venturi fill sequence
once sample is detected. If no sample is detected within
the duration of this block the fill sequence is automatically
stopped and a fill error activated, this could be due to dry
stream etc. The BioTector Sample valve opens once this
timer elapses also.
To account for variations in the stream the duration of this
block should be longer (~40%) than the typical time taken
for the sensors to detect sample once the ‘Filling Sampler’
message appears on the PLC Display.
2. If the sample is successfully detected during this timer the
sample is allowed to settle while the timer elapses. If the
site conditions require some settling of the sample prior to
sampling by the BioTector then this timer can be extended
to accommodate this need.
100
s
Default FILL SEQUENCE TIME 4 Stream
136
s
Default FILL SEQUENCE TIME 6 Stream
144
s
Note: B126 not included in calculation of FILL SEQUENCE TIME
The SAMPLER time in the BioTectors SAMPLE PUMP menu must be greater than FILL SEQUENCE
TIME of the Venturi Sampler. The FILL SEQUENCE TIME in seconds can be found by pressing the [+]
key on the PLC while in Standby Mode. This will automatically adjust if times are changed from default
settings to show the new FILL SEQUENCE TIME.
In the default configuration the fill sequence of the Venturi sampler takes 136 seconds, this allows 100s
for the Venturi sampler to fill its tubes and chamber, (the other ~40 seconds being used for the initial
purge of the Venturi sampler). This configuration is suitable for sites with a 40m sample line and a lift up
to approximately 5 to 6 meters. Longer sample lines will require the default time in both the Venturi
samplers PLC and BioTector Sampler setting to be changed.
