KROHNE IFC 110 Converter - Manual (Page 62)

Sect. 6.6 Part C Special applications, functional checks, service, and order numbers
62 IFC 110 F 05/2003
6.6 Unstable display and outputs
Unstable displays and outputs may occur:
– with high amounts of solids,
– with inhomogeneities,
– with badly blended mixtures,
– after constant chemical reactions in the process liquid or
– in ALTOFLUX 4000 F flow sensors when the wrong electrode material is selected for the
process liquid, e.g. Hastelloy B2 for hydrochloric acid.
If the flow is pulsating because of the use of diaphragm or reciprocating pumps please refer to
Section 6.5.
Resetting the signal converter, see Sections 4 and 5.
When changing the signal converter settings, the green LED (normal) and the red LED (error)
on the front panel of the signal converter start to flash rapidly and frequently. This indicates that
the A/D converter range is frequently exceeded and that not all measured values are evaluated.
Change the following settings to allow the display ripple to be properly evaluated:
Select ”BARGRAPH” in Fct. 1.04 DISPLAY, subfunction ”DISP. FLOW” and select ”YES” in
submenu ”DISP. MSG.”.
Press ↵ key 4 times to return to measuring mode.
The following displays are possible in measuring mode:
ADC = A/D converter range exceeded
and
OVERFL. I, P and/or P2 = one or several output ranges exceeded
Change procedure A
PLEASE NOTE:
After each of the following changes check if the display and outputs are unsteady in measuring
mode. Do not proceed to the next step unless the display and outputs continue to be unsteady.
• Fct. 1.02 TIMECONST. (change time constant)
– Set to ”ONLY I”; set to ”ALL” when pulse output is also unsteady.
– Set time constant to approx. ”20 seconds”, check if display remains unsteady and correct if
necessary.
• Fct. 3.06 APPLICAT. (adapt modulation limit of A/D converter to the application)
Change setting of subfunction ”FLOW” to ”PULSATING” on a trial basis.
When the green LED and red LED continue to flash,
change the setting of subfunction ”ADC GAIN” to 30.
Should the green LED and red LED continue to flash frequently, set value to 10.
• Fct. 3.02 FIELD FREQ. (change magnetic field frequency)
Change the setting to 1/2 on a trial basis.
If this has no significant effect, restore the last setting (usually 1/6).
Only recommended for PROFIFLUX 5000 F (DN 2.5-100 and
1
/
10
-4 inch)
and ALTOFLUX 4000 F (DN 10, 15, 50-100 and
1
/
10
,
1
/
2
, 2-4 inch),
for other types and sizes please consult factory.
If display and outputs continue to be unsteady or if the set time constant proves too high for your
specific application (Fct. 1.02) please proceed as described in change procedure B.