Instructions

UM-0085-B09 DT80 Range User Manual Page 230
RG
Queues
If an FTP/email data unload is performed, e.g.
COPYD dest=ftp://womble.com/data/?interface=eth
or an email alarm is triggered, e.g.
IF(1TK>50)"Overtemp"[mailto:[e-mail]?interface=eth]
then an entry will be added to the appropriate communication queue.
On a DT8xM model, the communications queues may contain items for the modem interface and items for the Ethernet
interface (the
interface= option is used to select which interface to use). On a standard model, all transfers will use
the Ethernet interface, so the
interface= option is not required.
As described in SESSION Command (P236), the SESSION LIST command can be used to view the contents of the
communications queues, and
SESSION CLEAR will delete all entries therein.
Session Timing
 Starting and Ending a Session
An Ethernet session begins when there is something that needs to be sent now, via Ethernet. This may be an FTP data
unload, an email data unload or an email alarm. It may be a newly generated item, or it may be a previously queued item
that now needs to be retried.
The session ends when:
• All transfers have been completed successfully, so there are no more Ethernet entries in the FTP or email
queues, or
• The queues have been manually cleared, using
SESSION CLEAR, or
• Some or all of the queued Ethernet transfers failed, and it is not yet time to retry them, or
• The Ethernet interface is found to be not functional (does not have a valid IP address)
If there is an active Ethernet session then the logger is kept awake until the session completes, at which point it is
allowed to sleep. If retries are required then the DT80 will automatically wake at the required time in order to start a new
Ethernet session.
Note: The SESSION START and SESSION STOP commands are not applicable to Ethernet sessions. Also, an Ethernet session
always starts immediately, so there are no "low priority" alarms or unloads.
 Retrying a Session
As with modem sessions, the SESSION RETRY command can be used to force the DT80 to attempt to start a session
and retry all queued items.
Plugging an Ethernet cable into the DT80 will also cause all queued Ethernet items to be immediately retried,
Session State
An Ethernet session can be in one of six states, as described in the table below. The SESSION command (no
parameters) will return the current state. System variable 85SV reflects the state of the Ethernet interface.
Ethernet Status
85SV
Description
Disabled
0
Ethernet port is disabled
No cable
0
Ethernet cable is not connected
Starting
1
IP address is being acquired
Ready 2
A valid IP address has been obtained. The Ethernet interface is usable, but an
Ethernet session is not currently active
Online
2
An Ethernet session is currently active
Limited connectivity
3
DHCP server not found, so a link-local IP address has been assigned
Error Handling
Ethernet session failures are handled in a very similar way to modem communications session failures. Refer to Error
handling (P232) for full details.
If an Ethernet session fails (e.g. the cable is removed, or it cannot obtain a valid IP address) then it will be retried after a
short delay, which can be set using
PROFILE ETHERNET_SESSION RETRY_DELAY_S=seconds
The default setting is 30 seconds, and every third delay will be 60 times longer to give some extra time to resolve the
problem.
If the session is established OK but an email or FTP transfer fails then it will be retried after the same delay time, again
with every third delay lengthened by a factor of 60. Use the
SESSION LIST command to see when the next retry is
due.