Technical data

Flow meter FC01-Ex Flow meter FC01-Ex
Technical implementation of customer calibration 25 Technical implementation of customer calibration 25
4 Technical implementation of customer calibration
The FC01-Ex can be used to establish a new pipe-depending curve, or to enter or store it as a
theoretical curve.
4.1 Calculation
Interpolation between the trim points is linear. This applies both to the velocity values and the
control variables to be assigned by the user, i.e. the velocity-dependent heating power required
to maintain a constant temperature differential between the medium and the heated probe in the
case of a calorimetric sensor.
Beyond the maximum and minimum trim point, extrapolation is made by 10% each of the
applicable upper measuring range value. As the sensor is not direction-sensitive, the minimum
flow value displayed will be zero.
Maximum number of trim points: 20
Minimum number of trim points: 2
The maximum trim point is assigned to the maximum velocity; the assignable velocity decreases
with a descending trim point index.
Definition:
V
n
(velocity assigned to setpoint n)
n = 2 … 20 (trim point index)
Condition for the trim points:
V
n
< V
(n+1)
..... ≥ 0
4.2 Calibration
4.2.1 Selection of CTD value (temperature differential)
It is possible to select an optional temperature differential setpoint, within a temperature limit of
3.0 °C and 15 °C, providing that 90% I
max
of this current heating power is not exceeded, to indi-
cate the temperature differential at max. flow velocity (90% I
max
Y = 36864 Digits).
Error (error 30) will be indicated if this limit is not observed during calibration. The user will then
have to select a lower temperature differential.
As different media have different heat transfer capacities (specific heat) and densities, CTD value
selection also depends on the medium to be measured.
Please see the following table and assignment list for guidance.
Class 1: gases
Class 2: granules, dust and other mixtures containing solids
Class 3: water and similar media, oils and other homogeneous liquids, and liquid mixtures
ˆ
=
4 Technical implementation of customer calibration
The FC01-Ex can be used to establish a new pipe-depending curve, or to enter or store it as a
theoretical curve.
4.1 Calculation
Interpolation between the trim points is linear. This applies both to the velocity values and the
control variables to be assigned by the user, i.e. the velocity-dependent heating power required
to maintain a constant temperature differential between the medium and the heated probe in the
case of a calorimetric sensor.
Beyond the maximum and minimum trim point, extrapolation is made by 10% each of the
applicable upper measuring range value. As the sensor is not direction-sensitive, the minimum
flow value displayed will be zero.
Maximum number of trim points: 20
Minimum number of trim points: 2
The maximum trim point is assigned to the maximum velocity; the assignable velocity decreases
with a descending trim point index.
Definition:
V
n
(velocity assigned to setpoint n)
n = 2 … 20 (trim point index)
Condition for the trim points:
V
n
< V
(n+1)
..... ≥ 0
4.2 Calibration
4.2.1 Selection of CTD value (temperature differential)
It is possible to select an optional temperature differential setpoint, within a temperature limit of
3.0 °C and 15 °C, providing that 90% I
max
of this current heating power is not exceeded, to indi-
cate the temperature differential at max. flow velocity (90% I
max
Y = 36864 Digits).
Error (error 30) will be indicated if this limit is not observed during calibration. The user will then
have to select a lower temperature differential.
As different media have different heat transfer capacities (specific heat) and densities, CTD value
selection also depends on the medium to be measured.
Please see the following table and assignment list for guidance.
Class 1: gases
Class 2: granules, dust and other mixtures containing solids
Class 3: water and similar media, oils and other homogeneous liquids, and liquid mixtures
ˆ
=