Commissioning; Electrical Testing Of Connections - Pepperl+Fuchs LB Series Manual

LB Remote I/O System

Commissioning

4 Commissioning
4.1

Electrical Testing of Connections

Make sure that the terminators have been properly fitted to the fieldbus and the service bus.
See chapter 3.14
Test of Physical Connection Right to the End of the Segment
Tip
Perform the measurements from the control room.
1. Disconnect the bus connector from the master.
2. Deactivate the terminator on the bus connector (bus start).
3. Measure the voltage at the bus connector between A (pin 3) and B (pin 8).
A voltage of U = 220  / (220  + 2 * 390 ) * 5 V = 1.1 V must be present between A
and B. This voltage comes from the field-side terminator.
If the 1.1 V voltage is not present, there is either no terminator connected at the end, the
cable is faulty, or there is no terminating voltage at the remote I/O station.
4. Measure the current at the bus connector between A (pin 3) and B (pin 8).
It must be possible to measure a current of I = 5 V / (2 * 390 )  6.4 mA between A and
B.
If the current is significantly higher, by a factor of 2 or more, the bus is terminated using
more than one terminator.
If the current is I  0 mA, then either there is no terminator present, the cable is faulty, or
there is no terminating voltage. In this case, a resistance of 220  should be measured
between A and B.
If no current or resistance can be measured, the terminator at the end of the bus is missing
or the cable is faulty.
5. Activate the terminator on the bus connector for the master.
6. Plug the bus connector back into the master.
Test of Physical Remote I/O Station Connection
Danger!
Risk of explosion
When taking measurements in hazardous areas, there is a risk of explosion from sparks
forming.
Take measurements on the terminal connections of a remote I/O station, with a hot work permit
only, in other words when there is no potentially explosive atmosphere.
1. Disconnect the bus connector from the master.
2. Deactivate the terminator on the bus connector (bus start).
3. Measure the voltage between A (pin 3) and B (pin 8) on the bus connection of each remote
I/O station.
A voltage of U = 1.1 V must be present between A and B on each remote I/O station.
4. Activate the terminator on the bus connector for the master.
5. Plug the bus connector back into the master.
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