DRIVER INTEGRITY TEST

for RS-485

When operating correctly, the ZETSENSOR digital devices are displayed in the Device Manager program included in the ZETLAB Software Package.

If a digital sensor is not discovered by PC, the possible cause is the faulty RS-485 interface driver. To check this, proceed as follows.

Check the midpoint voltage

Use a multimeter and 120 Ohm resistor for the check.
Switch the multimeter to DC voltage measuring, assemble the circuit according to the figure and determine the voltage between the relevant terminals.

проверка_1

The rated voltage for each terminal pair is specified in the table below.

Terminal pair	Voltage
“DATA -” – “GND”	1.5 to 3 V
“DATA +” – “GND”	1.5 to 3 V
“DATA -” – “DATA +”	∼50 mV

Resistance check

Caution

THE SENSOR MUST BE POWERED OFF.

Switch the multimeter to resistance measuring, assemble the circuit according to the figure, and determine the resistance between the relevant terminals.

проверка_2

The rated voltage for each terminal pair is specified in the table below.

Terminal Pair	Voltage
“DATA -” – “GND”	> 100 kOhm
“DATA +” – “GND”	> 100 kOhm
“DATA -” – “DATA +”	120 Ohm

DRIVER INTEGRITY TEST

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