inout NP2 Quick Manual page 15

RS485 settings
Device ID : Address NP2/NP5 in the 485 bus. This address MUST be univocal, two
devices with the same address can not co-exist on the same bus.
Response delay: Minimum delay between end of reception of the pack and delivery of the reply.
NP2/NP5 can be connected to an RS485 communication bus through a serial port, which is
controlled from a master system or by a computer.
Due to interference from outside the serial line, one may find anomalous behaviour from part of
the master system which could cause possible damage to NP2/NP5. To avoid this mishap one
must take the following precautions:
1. Do not let the serial cables transit in the same conduits as power cables or cables with
elevated voltage. Maintain a safety distance of at least 10 cm. between these cables.
2. Connect serial cable screen to the ground the on one of the two sides (do not connect the
screen from both sides); in addition, the ground connection of the screen must not be made in
the same point in which piloted circuits of elevated tension are connected.
3. Cut the voltage of the entire system before beginning the wiring of the serial lines: even
dispersed or parasite currents could damage the modules.
IMPORTANT:
 The internal electronics of NP2/NP5 are not galvanically insulated from the RS485 line; in
case of short circuit or discharge to ground, it is possible to damage not only the NP2/NP5, but
even the master system to which it is connected!
 For the RS485 connection, one must remember to ignore the transmission echo from the
master that is returning through the serial line.
NP2/NP5 QUICK GUIDE v. 1.5
Pag. 14