Sullair Supervisor 2 Deluxe, Operator'S Manual

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Section 6
SUPERVISOR PROTOCOL
6.1 OVERVIEW
This document describes features that are more technical in nature than the normal opera-
tion of the machine, in particular sequencing and communication. This information may be
used for the design of monitoring systems of controllers. Communications connections are
included with all Supervisor II Deluxe controllers. A communications module is added to
standard Supervisor controllers for any external communications. Most features are com-
mon to either controller, unless specifically noted below.
The communications link is a RS-485 (two wire) serial line. The following three parameters
must be set correctly to be able to communicate through this link.
COM ID# Unique number for each machine on the link.
BAUDRATE Must be the same for all machines (default is 9600).
SEQUENCE Sequencing mode Refer to earlier sections for full descriptions of sequencing
operation. The function of the link is specified by the setting of the Sequence parameter as
follows :
DISABLED, REMOTE - Responds to status and parameter change queries.
HOURS, COM ID# - Broadcasts net status message about once a second, responds to sta-
tus and parameter change queries during monitor time slot. In this manner, each machine
knows the status of every other machine. Sequencing decisions are made individually by
each machine based on the status of all on line machines in the system. Collisions on the
serial channel are avoided by a time slice scheme (See section on Time Slice).
6.2 ADVANTAGES OF BROADCAST MODE
• System operation is not dependent on a single master controller.
• Because there is no master, the number of messages are cut in half (decreasing
response time). In master/slave mode the master must send a message to request
status and the machine must send a message back. In broadcast mode, each
machine sends it’s status approximately once a second.
• When a machine goes off line or on line there is no need to poll for a new master.
Individual machines may be taken off line or put on line with no effect on communi-
cations. This is handy for maintenance or when a machine is to be controlled manu-
ally. When the machine is stopped it still sends net status messages so other
machines or a monitor can display it’s status. When the machine is DISABLED it will
not send net status messages but will respond to status and parameter change mes-
sages.
• Because decisions are made locally, the response of the system is very good; less
than one second for trimming, loading and unloading. One second plus starting time
for a machine to start.
• There are no extra communications for monitoring. Since each machine sends its sta-
tus every second, the monitor does not need to send messages. However, the moni-
tor may send messages to get other status, or change parameters.
• The monitor does not need to be continuously connected. A monitor may be con-