Bronkhorst CORI-FILL - Manual (Page 24)

9.17.075
Bronkhorst Cori-Tech BV
24
10 Troubleshooting
Symptom Possible cause Action
Suddenly a wrong value will be dosed
among a sequence of right values
when using on-off dosing with shut-off
valves.
(Back) pressure waves caused at
valve closing with high force might
give erratic reading at (mini) CORI-
FLOW.
Sudden pressure in- or decrease.
Select a different valve type
Make sure to have some volume or
dampener between valve and meter
Monitor ‘hardware error’ at alarm info
byte at instrument interface to indicate
this
Monitor ‘counter value’ at instrument
interface to detect this
Check inlet pressure
Even when dosing time is very short
flow signal is too slow
Filter settings might be not optimal.
Exponential smoothing filter value
probably too low.
Change exponential smoothing filter
setting. See section 5.
Large deviation on sequential batches Filter settings might be not optimal.
Exponential smoothing filter value
probably too high.
Change exponential smoothing filter
setting. See section 5.
Supply pressure not stable Check and stabilize pressure
Controller settings not optimal Increase control stability by optimizing
PID settings.
Flow signal is >130% Pressure too high Lower the supply pressure
Resistance of flow line too low Restrict the flow by using a manual valve
PID-Kp too high Select a lower Kp value
FS value (capacity) too low Increase the FS (capacity) value
Dosed value is not accurate enough Flow meter has wrong zero point Perform new auto-zero
Too many gas bubbles in liquid Purge the flow meter
Vibrations disturbing the meter Follow instructions for mounting
Flow signal >130% Try to limit flow signal < 130%
Dosing time is too short Increase dosing time
Proportional dosing is too fast Adjust counter control gain to ensure
last part of dosing at 2%
Counter control gain too low
(Dosing too long at low flow)
Increase counter control gain to dose
longer at high flow (more accurate)
Reference instrument to check with is
not a weighing scale (e.g. volumetric
device)
Use a weighing scale and handle it
according to the instructions
Proportional dosing @2% gives too much
overshoot
Lower flow rate (dosing speed) or enable
overrun correction
Air in the system causes drifting Try to purge the air out of the system