Frequency Measurement (Hz) - Omega CA450 User Manual

) Turn the function switch to the "
("LOOP POWER" appears on the display.)
A constant voltage of 24 VDC is output between the "SOURCE(+)" and "SOURCE(-)"
measurement terminals.
2) Connect the red test lead to "SOURCE(+)" and the black test lead to "SOURCE(-)."
) Connect the test leads to the circuit under measurement, and then read the values when
they stabilize.
Just as in mA measurement, the main display shows the measured value, and the
subdisplay shows the value of the measured value divided by the current span times 00
(%). (See chapter 4.3.7.)
4) Press SELECT to turn the internal 250 Ω series resistor for HART communication on.
("250ΩHART" appears on the display.) Press SELECT again to turn the internal resistor
off.
Tip
The loop power is supplied at the typical value of 2 VDC. Depending on different
conditions, such as the loop current value or whether there is a internal series resistor,
the voltage across the terminals may be greater than 2 V.
4.3.9

Frequency Measurement (Hz)

) Turn the function switch to the "~V " position.
2) Press the Hz key to select frequency measurement.
(The measured frequency value and unit appear in the
main display, and the measured voltage appears in the
subdisplay.)
) Insert the test leads into the input terminals.
) Connect the test leads to the circuit under measurement,
and then read the values when they stabilize.
Tip
Note that range hold and selection operations performed using the Range key only
apply to the subdisplay (measured voltages).
LOOP POWER" position.
28
Test leads
Black Red