Technical data

4.2.5.2 Old curve
In this operating mode, each trim point can be corrected without jeopardizing other existing data.
Changes are limited by the general calibration conditions. This means that the values assigned
to a trim point can never be higher than the values assigned to the trim point above, or lower
than the quantities assigned to the trim point below.
Caution!
Changes/expansions of old curves must only be made whilst maintaining the temperature
differential.
4.2.6 Transfer of C- and T values - Re-establishment of T value
As the monitoring heads are factory preset for air or water, their C and T values apply only to
those media.
When the heads are used in gases or gas mixtures similar to air (see table page 26), these values
can be transferred. The same applies to heads monitoring water.
In that case the temperature difference (water 3.3 °C, air 10.5 °C) must be set in the CUSTOMER
TRIM menu to calibrate a characteristic curve.
The following medium characteristic quantities should however harmonize as far as possible:
a. density ρ
b. specific heat c
When other media are used, the C value may be transferred, but the T value should be separately
established and set for recording the new curve at T = 50.
4.2.6.1 Establishing the T value - general
The T value should be established at a velocity in the upper third of the calibration range.
When recording the characteristic curve, the temperature and the control variable at a trim point
located in the upper third of the characteristic curve (70 - 80% V
max
) should be noted.
T1 = . . . , . °C medium temperature when recording the new curve
Y
T1
= . . . . . digits control variable
V
T1
= . . , . . m/s flow velocity at temperature T1
Control variable Y
T2
is then established at the same flow velocity (V
T2
= V
T1
), ideally at the highest
medium operating temperature.
Conditions: V
T1
= V
T2
T2 > T1
The following quantities are recorded:
T2 = . . . , . °C upper setting temperature of the medium
Y
T2
= . . . . . digits control variable with T2
Flow Meter FC01-Ex Flow Meter FC01-Ex
30 Technical implementation of customer calibration 30 Technical implementation of customer calibration
4.2.5.2 Old curve
In this operating mode, each trim point can be corrected without jeopardizing other existing data.
Changes are limited by the general calibration conditions. This means that the values assigned
to a trim point can never be higher than the values assigned to the trim point above, or lower
than the quantities assigned to the trim point below.
Caution!
Changes/expansions of old curves must only be made whilst maintaining the temperature
differential.
4.2.6 Transfer of C- and T values - Re-establishment of T value
As the monitoring heads are factory preset for air or water, their C and T values apply only to
those media.
When the heads are used in gases or gas mixtures similar to air (see table page 26), these values
can be transferred. The same applies to heads monitoring water.
In that case the temperature difference (water 3.3 °C, air 10.5 °C) must be set in the CUSTOMER
TRIM menu to calibrate a characteristic curve.
The following medium characteristic quantities should however harmonize as far as possible:
a. density ρ
b. specific heat c
When other media are used, the C value may be transferred, but the T value should be separately
established and set for recording the new curve at T = 50.
4.2.6.1 Establishing the T value - general
The T value should be established at a velocity in the upper third of the calibration range.
When recording the characteristic curve, the temperature and the control variable at a trim point
located in the upper third of the characteristic curve (70 - 80% V
max
) should be noted.
T1 = . . . , . °C medium temperature when recording the new curve
Y
T1
= . . . . . digits control variable
V
T1
= . . , . . m/s flow velocity at temperature T1
Control variable Y
T2
is then established at the same flow velocity (V
T2
= V
T1
), ideally at the highest
medium operating temperature.
Conditions: V
T1
= V
T2
T2 > T1
The following quantities are recorded:
T2 = . . . , . °C upper setting temperature of the medium
Y
T2
= . . . . . digits control variable with T2