Chapter 11 Distributed Control; Overview; Configuring Distributed Control - Galil Motion Control CDS-3310 User Manual

Chapter 11 Distributed Control

Overview

In the "distributed" mode of operation, the CDS-3310 is used in conjunction with up to 7 other CDS-
3310s connected via Ethernet. Programming is simplified because multiple controllers behave as a
single multi-axis controller. For example, the commands PR1000,1000,1000; BGXYZ issued on the
master CDS-3310 will initiate motion on three controllers. In this case, the master CDS-3310 controls
the X axis, the first slave CDS-3310 controls Y, and the second slave CDS-3310 controls Z. Only the
master controller requires an application program and/or the host PC communicates only with the
master controller. The following commands are used for distributed control: HA, HC, HQ, HW, ZA,
and ZB. DISTRIBUTED CONTROL MUST BE PERFORMED ON A CLOSED MACHINE
NETWORK.

Configuring Distributed Control

The HA command establishes the axis order (YZWEFGH) of the slave controllers by controller serial
number and the HC command configures all the slaves in a particular system. HC uses the BOOTP
packets from the slaves to automatically select IP addresses and set up the system.
The HC command indicates the number of axes (including the master), update rate, and type of
communication. The data update rate specifies the rate at which each slave sends a data packet to the
master containing current status information. These "slave data records" are used by the master
controller to make decisions based on the status of the slave controllers.
The data contained in the record is as follows:
In order for the HC command to be initiated, an IP address must first be assigned to the master (see
chapter 2). The slaves will typically remain without IP addresses.
Once HC is initiated, the master controller will listen for BOOTP packets from the slave controllers
without IP addresses. As it receives these packets, the master will configure the slave axes according
to the HA command. Once this connection has been established, the master will initiate the slave data
records.
78 • Chapter 11 Distributed Control
reference position
encoder position
position error
velocity
torque
limit and home switches
axis status (in motion, motor off, at speed, stopcode)
uncommitted inputs
uncommitted outputs
two user-defined variables (ZA and ZB)
CDS-3310