Owner's manual

5-2 SECS Scenarios
5.1.3 Simultaneous Establish Communications
Assumption: Equipment’s Communication state is “Enabled/Not Communicating”.
Table 5-3 SECS Messages Simultaneous Establish Communications
Step SECS Message Description
1 H <- E S1F13 W Equipment sends Establish Communications Request.
2 H -> E S1F13 W Host sends Establish Communications Request.
3 H <- E S1F14
The Equipment responds with Establish Communications
Acknowledge, with COMMACK set to zero. After this message
is successfully sent, communications is established. The
Equipment changes its communication state to Communicating.
4 H -> E S1F14
The Host responds with Establish Communications
Acknowledge, with COMMACK set to zero. This step could
occur before Step 3, in which case communications would be
established at this step.
5.1.4 Losing Connection, Re-Connecting
Table 5-4 SECS Messages Losing Connection, Re-Connecting
Step SECS Message Description
1 H <- E SxFy
Any Message. The Equipment encounters SECS block
transmission errors while attempting to send a message to
the Host., and reaches its Retry Limit (RTY). The Equipment
considers the SECS link as disconnected. Spooling will
become Active if enabled.
2 H <-E S1F13 W
Connect Request. The Equipment attempts to re-establish the
link.
3
If the send is not successful, or if no reply is received from the
Host, the Equipment waits for
“EstablishCommunicationsTimer” seconds and then goes
back to Step 2.
4 H -> E S1F14
The Host acknowledges, sending COMMACK of “0”. The link
is now re-connected.
5.1.5 Heartbeat
Table 5-5 SECS Messages Heartbeat
Step SECS Message Description
1 H <- E S1F1 W
Are You There. The Equipment sends this message
periodically to determine if the SECS link is still intact.
2 H -> E S1F2
On Line Data. The Host replies. The Equipment knows that
the link is still intact.