VDH Products PROBA, Инструкция по установке и эксплуатации

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VDH Products BV Document 063319 - version 3.12 Page: 37 of 78
4.3 Network and the PROBA120
The VDH network is a 'daisy-chain' type network. This means the connection from the PC (over the PROBA120 , the
interface) goes from PROBA110 to PROBA110 . It is not allowed to connect the last PROBA110 back to the PROBA120 , so
that a loop is made. Do not make branches.
The connection between the PC and the PROBA110 's consists of a shielded cable with two conductors of minimum 0.75
mm² (see Appendix L, page 72). It is recommended to use a cable with twisted wires, because this type of cable is less
sensitive to disturbances from outside.
On the PROBA120 the network cable is connected to the connection on the right bottom side.
It is important that the shielding is connected to ' SHLD '. This is the only point at which the shield is connected
to anything ! (so don't ground the shield somewhere else).
Both conductors are to be connected to the two other points ('
LO ' and ' HI ').
The network connections of the PROBA110 are located on the relay board. On the right hand side are two
sets of connection strips. These are marked with ' SHLD ', ' LO ' and ' HI '.
It does not matter to which of the sets the incoming cable is connected. On the
board itself the two connections with the same name are wired together. Try to
connect the cables in one installation in the same way (e.g. incoming cable at the
topside, outgoing at the bottom); this eases the troubleshooting if something is
wrong.
If no outgoing cable is present, the second connecting needs to be shut off with a
resistor. This shut-off resistor is standard mounted on the lower connection.
The terminals ' LO ' and ' HI ' should not be changed.
The shield of the cable transmits a small voltage. Take care that it is not shorted
to anything else e.g. ground.