Page 10Manual SVM 4G modem | Back to Index
Adesys B.V. | Wateringen
Inservermode,thefollowingsettingsarepossible:
Transparent (RS-232 connected)
IfadeviceisconnectedtotheSVMviaRS-232andmodememulationisswitchedo,theservermode
connection structure is transparent.
The server application can take the initiative to establish a connection and is transparent as soon as the
localandexternalconnectionshavebeenestablished.Therefore,nomodemisemulatedinthismode,but
the connection immediately becomes transparent.
Inthismode,too,acongurablestartstringcanbesenttotheserverapplication(SCADA)toinformitthat
the PLC is ready. Status changes at the contact inputs can also be reported in this mode.
Modem emulation (RS-232 connected)
Inservermode,theexternalserverapplicationcantaketheinitiativetoestablishaconnection.Depending
upon the auto-answer command ATS0, the connection will become transparent either automatically
ornotuntiltheapplicationhassenttheanswercommandATA.Fortheserverapplication(SCADA),the
connection (with the SVM) is ready immediately, whilst the local connection between SVM and PLCE does
notyetneedtobetransparent.Acongurablestartstringcanbesenttoinformtheserverapplication
(SCADA)whentheconnectionhasbeenfullyestablished(istransparent).
ACONNECTisthussenttotheserialport.ThevariousRS-232signals,suchasDCD,DTR,RI,etc.,arealso
supported. Status changes at the contact inputs can also be reported in this mode.
In this mode, the IP address obtained can be requested with the ATI4 command. This is particularly handy
if the set IP address is unknown, but this information is needed by the installer on site.
3.5.3. Server/clientmode
If the server/clientmode is switched on, the SVM waits in idle mode until a connection is established from
outside. If, however, the status of the contact inputs changes, or if data is sent to the RS-232 port/Ethernet
port, the SVM switches to clientmode and takes the initiative for the connection.
3.6. Advancedconnectionsettings
3.6.1. Connectionstringuponinitialconnection
A string has to be set up for sending to the server application as soon as the connection is transparent.
This informs the server which device is connected and that it is possible to communicate. This string is
senttotheserverapplicationwhenaconnectionisestablishedinthefollowingsituations:
• RS-232 connected, servermode;
• RS-232 connected, clientmode autologon.
3.6.2. Time-outs
Various time-outs have been implemented to prevent the modem from getting stuck in a particular state
due to unforeseen events. These ensure that the modem is reset and will then return to idle mode.
Data time-out
This time-out occurs if there is a connection to the server, but data is no longer coming in via the 4G
network.
• Timecongurablebetween1and10800minutes(7days).
• If the value 0 is entered, this time-out is not active.
Connect time-out
This time-out occurs if the connection with the server takes longer than the set period of time.
• Timecongurablebetween1and168hours(7days).
• If the value 0 is entered, this time-out is not active.
No activity time-out
This time-out occurs if there has been no connection with the server for a set period of time.
• Timecongurablebetween1and168hours(7days).
• If the value 0 is entered, this time-out is not active.
3.6.3. Terminateconnectionintheeventofalarm
If an alarm occurs whilst the SVM is sending data, in this option it is possible to choose whether the data
connectioncanbeterminatedsothatthealarmnoticationcanbesent.
