Avery Berkel CX20 SERIES, Service Manual

Page: 213 / 353

21 — Networking
21–3 CX20/CX30/CX34 Service Manual
21.1 Networking
IMPORTANT (1):
The network’s cable screen MUST be connected to the chassis
of each network machine.
IMPORTANT (2):
An ISC link between machines with Phase 1.3 software release
and machines with pre–Phase 1.3 software release is not
possible.
NOTE: The ISC map, held in a slave, will revert to ’stand alone’ map when
the slave scale is disconnected from a system.
The CX20/CX30/CX34 machines can be included in a network. Each unit is
capable of being networked as either a Master or a Slave unit. The Master
supplies the current source for the system (unless a communications controller
is fitted – see Section 22). All units communicate with the network through
optical isolators.
Figure 21.1 Network Connections
SLAVE SLAVE
MASTER
1 3
6 7
Screen
Network
Lead
Machine’s Earth
1 3
6 7
1 3
6 7
9–way D–type plugs
Cable screen connected to chassis
(at each machine)
Cable shielded
Single
twisted
pair
Conductor 1
Conductor 2
All units on the network can transmit certain data, such as transaction details,
totals, and operator–identifying codes; this data is acquired and processed by
the Master unit. If there is a large amount of network traffic being controlled by
the Master unit, the operation of the Master unit is slowed because of the
processor work load: the communications controller (comms PCB) option can
help with this (refer to Section NO TAG22). The Master unit is the only unit
enabled to transmit PLU data updates to all machines on the network.