C. OPERATION
C.1 Reminders of the 4-wire Principle
The principle of this connection is shown in the diagram below.
Ri = Unit internal resistance.
Rf = Measurement wire resistance.
Rc = Contact resistance.
Rx = Resistance to be measured.
From a DC voltage source U, a generator supplies a current of value I.
A voltmeter measures the voltage drop Ux at the terminals of the resistance to be measured Rx and displays
Rx = Ux / I.
The result is not affected by the other resistances encountered in the current loop (Ri, Rf, Rc), as long as the
total voltage drop induced across Rx remains below the voltage supplied by the source U
(5 VU 6 V). The maximum admissible wire resistance level is Rf≈ (U-Ux) / I
C.2 Performing a Measurement
1. Press to switch the unit on.
2. Press to choose the measurement range.
3. Press to choose the measurement mode:
inductive, low inductive, low inductive and automatic triggering.
4. Press to implement temperature compensation.
5. Press to switch the alarms on.
6. Connect the measurement wires to the connectors and connect them to the resistors.
7. Press to start measurements.
To Next Page
Loading...
