Message Control : Poll modem

[crl_snef]

Hello,

for a client using text-to-speech message control, we are using an application with redundant servers, one modem connected to each server.

The goal is to switch servers if modem1 is down, to keep voice messaging functionnality :
=> Is it possible to (and if so, how to) test if modem of main server is still alive ?

(we are using USR5637 modems for our tests)

[konstantinf]

Hello and welcome to the COPA-DATA Forum!

the easiest way would be to use a modem which supports SNMP. Then you could react on a variable and initiate a redundancy switch.
Maybe you are also able to detect the failure via VSTA but I'm not sure about this.

It would be great if there would be a system variable which detects if the modem fails.
I've sent this idea to our product management - maybe this will be in a future version of zenon

Regards,
Konstantin

[crl_snef]

Hello Konstantin,
thanks for your reply.

I already tried to detect the failure via VBA, using AT commands via a control MSComm :

Public Function isAliveModem() As Boolean
    
    Dim strInput As String

    isAliveModem = False
    'Debug
    Stop
    'Port settings
    modem.CommPort = 4
    modem.Settings = "115200,n,8,1"
    'Open com port
    modem.PortOpen = True
    'Send "AT"
    modem.Output = "AT" & vbCr
    'Wait for answer
    sleep 2000
    'Read answer
    strInput = modem.Input
    'if modem is alive : we should receive "OK"
    If InStr(0, strInput, "OK") Then
        isAliveModem = True
        Stop
    Else
        isAliveModem = False
        Stop
    End If
    Debug.Print (strInput)
    'Close com Port
    modem.PortOpen = False

End Function

It works fine as long as the port isn't already opened by Zenon at start-up (in this case, the command PortOpen = true sends error "comNoOpen 8012 The device is not open").

I was wondering if control used by zenon (or however zenon manages the modem) is usable directly by developer in VSTA ?

Regarding SNMP, could you advise a modem that supports it and has been tested for text-to-speech in Zenon ?

Regards,
Clément.

[konstantinf]

Hello Clément,

I fear the check doesn't work because the COM-port is still occupied by the zenon RT.

Regarding the SNMP modems, none of the modems we tested in-house supports SNMP.
Also in the thread "modem that are tested by COPA-DATA.." I couldn't find any modem that supports SNMP.

Regards,
Konstantin