Owner's manual

SECS Scenarios 5-1
5 SECS Scenarios
Unless otherwise noted in this section, the Communications State is “Communicating” and the Control
state is either “On-Line/Local” or “On-Line/Remote”.
5.1 Equipment Communications
5.1.1 Equipment Establishes Communications
Assumption: Equipment’s Communication state is “Enabled/Not Communicating”.
Table 5-1 SECS Messages Equipment Establishes Communications
Step SECS Message Description
1 H <- E S1F13 W Equipment attempts to send Establish Communications Request.
2
If the send is not successful, or if no reply is received from the
Host, wait “ESTABLISHCOMMUNICATIONSTIMER” seconds,
then go to Step 1.
3 H -> E S1F14
The Host responds with Establish Communications Acknowledge.
If COMMACK in this message is non-zero, wait
“ESTABLISHCOMMUNICATIONSTIMER” seconds, then go to
Step 1. If COMMACK is zero, proceed to the next step.
4
Communications is successfully established. The Equipment
changes its communication state to Communicating. Normal
SECS message processing begins.
5.1.2 Host Establishes Communications
Assumption: Equipment’s Communication state is either “Enabled/Not Communicating” or
“Enabled/Communicating”.
Table 5-2 SECS Messages Host Establishes Communications
Step SECS Message Description
1 H -> E S1F13 W Host sends Establish Communications Request.
2 H <- E S1F14
The Equipment responds with Establish Communications
Acknowledge, with COMMACK set to zero. After this message
is successfully sent, communications is established. If the
current communication state is “Not Communicating”, the
Equipment changes its communication state to
“Communicating”. If the state is “Communicating”, no change in
communication state occurs. In either case, subsequently
received messages are processed normally.