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SIPLACE GEM SW Version GEM 505.01 HOST Interface Manual ©Siemens AG, all rights reserved page 137 of 236 5.1.2 Host Establishes Communications Assumption: Equipment's Communication st ate is either "Enabled/Not…

SIPLACE GEM SW Version GEM 505.01 HOST Interface Manual

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".

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.

SIPLACE GEM SW Version GEM 505.01

HOST Interface Manual

5.1.2 Host Establishes Communications

Assumption: Equipment's Communication state is either "Enabled/Not Communicating"

or "Enabled/Communicating".

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.

5.1.3 Simultaneous Establish

Assumption: Equipment's Communication state is "Enabled/Not Communicating".

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.

SIPLACE GEM SW Version GEM 505.01 HOST Interface Manual

5.1.4 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

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.