Commissioning/Configuration
EP3204 and EP3314
36
Version: 2.2
6.2.1.2
3-wire resistance measurement
•
With the 3-wire measurement
◦ a defined current is initially applied between the contact points RL+ und RL- and the resistance
between them is determined on the basis of the voltage drop.
◦ The same procedure is subsequently carried out at the contact points RL+ und R-.
◦ The difference between the two measurements is the line resistance of one of the cores of the
sensor cable. By knowing the line resistance the resulting measuring error can be compensated.
◦ The cores of the sensor cable must have the same resistance in order for the method to work.
Fig. 24: Resistance measurement with a 4-wire, 3-wire and 2-wire connection technique
Summary of Contents for EP3204
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