Bronkhorst LIQUI-FLOW mini (till 01-07-2013) - Manual (Page 9)

9.17.065 page 9
2.10 Zeroing
The zero-point of each instrument is factory adjusted. If so required the zero point may be re-
adjusted over RS232 or by means of using the micro switch. Refer to section 4.1.4 for auto-zeroing
procedure over RS232. Procedure for zeroing by micro switch:
♦
Warm-up, pressure up the system and fill the instrument according to the process
conditions.
♦
Make sure no flow is going through the instrument by closing valves near the instrument.
♦
The sensor signal should be stable; any unexpected sensor instability may be caused by leaks
or trapped gas bubbles.
♦
Press micro switch and hold it. After a short time the red LED will go ON and OFF, then the
green LED will go ON. At that moment release the micro switch.
♦
The zeroing procedure will start at that moment and the green LED will blink fast. The
zeroing procedure waits for a stable signal and saves the zero. If the signal is not stable,
zeroing will take long and the nearest point to zero is accepted. The procedure will take
approximately 10 seconds.
♦
When the indication is showing 0% signal and the green indication LED is burning
continuously again, the zeroing action was succesful.
2.11 Calibration
Each LIQUI-FLOW mini instrument is factory calibrated. Bronkhorst High-Tech certifies that all instruments meet the
rated accuracy. Calibration is performed using measurement standards traceable to the standards of the Dutch
Metrology Institute (VSL). Calibration certificates are included in the shipment. When operated properly (clean liquid,
no pressure shocks, no vibrations, no thermal shocks, etc), regular maintenance is not required. However, periodical
inspection, recalibration or verification of the accuracy may be subject to individual requirements of the end-user.
2.12 Supply pressure
It is recommended to turn on power before applying pressure on the instrument and to switch off
power after removing pressure.
Turn on fluid supply gently. Avoid pressure shocks and bring the instrument gradually up to the level of
the actual operating conditions. Also switch off fluid supply gently.