SMART Pressure Transmitter
FT3351 Series User Manual
July.2022
18 |
P a g e
FAHM Co
.
Industrial Automation
Doc. FT3351Rev1401-05
The unit of low trim value is same as primary variable.
When this menu appears on LCD it show the current measurement of process pressure. So after
stabilizing of process pressure user should enter his desired pressure value (ordinary zero).
After calibration, the device should show the desire pressure which is specified by user.
3.2.3
Custom Variable
The custom variable is a mathematical variable which is related to primary variable with a linear
or square root equation. Ordinary this variable is used to represent scaled value on display
instead of the primary variable. For example in orifice applications you can use this variable to
show the flow of fluid while the transmitter sends the differential pressure of orifice to DCS.
Configuration of custom variable is performed via following parameters:
3.2.3.1
Max Range and Min Range and Transfer function
User can determine the maximum and minimum value of variable which will be mapped to
maximum and minimum of primary variable. After this configuration when the process pressure
be equal to min-pressure, the custom variable represents the minimum value and when it be
equal to max-pressure, the custom variable represents the maximum value.
According to transfer function selected by user, for value between min and max pressure values,
the custom variable value will be produced with linear or square root curve.
parameter
display
Parameter tuning structure
Custom Variable
Max-Range
(The value mapped
to 20 mA)
Press <M> until this page is appeared on LCD. Then press
<Z> to access the amount of maximum value (programing
mode). You can change the amount of digits by <S> and
change the point and position of digits by <Z>. After
tuning this parameter, press the <Z> until all characters
blink. Then press <M> for the saving new parameter and
switching from programing mode to operation mode.
Custom Variable
Min-Range
(The value mapped
to 4 mA)
Press <M> until this page is appeared on LCD. Then press
<Z> to access the amount of minimum value (programing
mode). You can change the amount of digits by <S> and
change the point and position of digits by <Z>. After
tuning this parameter, press the <Z> until all characters
blink. Then press <M> for the saving new parameter and
switching from programing mode to operation mode.
Custom Variable
Transfer
Function
(linear or SQRT
function)
Press <M> until this page is appeared on LCD. Then press
<Z> to access the custom variable transfer function
(programing mode). You can select linear or SQRT
function by pressing <S>. After that, press <Z> until all
characters blink. Then press <M> for the saving new
parameter and switching from programing mode to
operation mode
The unit of min and max values is arbitrary.
