ABB FSM4000-SE41F Operating Instruction page 89

7.4.1.3 Determining the coil temperature
The coil temperature is a factor of the ambient and fluid temperatures. The measurement can,
e.g., be used to monitor overtemperature due to the fluid.
The coil temperature is measured indirectly via the coil DC resistance (ABB patent GB 2 348
011).
To perform this measurement, it is necessary to switch on one of the relevant errors or warnings
in the submenu "Diagnostics / Alarm Settings" (see page 82).
T
Coil
T
Coil
R
Coil
Important
The coil resistance of the flowmeter sensor must be adjusted for a reference temperature. This
applies to newly shipped systems SE41F / SE21 and S4. When connecting an S4 transmitter
to already shipped transmitters SE41F / SE21, it is also necessary to perform the adjustment.
For additional information, see chapter "7.4.4 Readjusting the coil temperature".
7.4.1.4 Determining the insulation resistance for the coil
To perform this test, it is necessary to switch on one of the relevant errors or warnings in the
submenu "Diagnostics/Alarm Settings" (see page 80).
D184B140U02

R R
Coil Re f
 
= 20 C


R
Re f Re f
 Coil temperature
 Coil resistance
G00578d
 Reference coil resistance at 20 °C
R
Ref

 Temperature coefficient of copper at
Re f

20 °C (0.39%/K)
Detecting problems with the coil insulation. Can be caused,
e.g., by dampness in the flowmeter sensor or in the connection
box.
When determining the insulation resistance of the coil to
ground, a DC field test signal of approx. 1 sec is sent to the coil,
separating the ground connection in the transmitter. In spite of
the separation provided by the coil, the current flowing to
ground is used to calculate the insulation resistance.
During this measurement, the flowrate cannot be measured and
the most recent value is retained.
FSM4000
Parameterization
89