Dynamic Model

There is a function in Dynamic Model scripting, to get the value of a particular OID, while polling.

for eg: To show the Uptime of a device, - this can be done using Dynamic Model scripting, by the following method.

1. create an attribute for Uptime.

2. use the following method to get the uptime.

instrument SNMP{
        systemUptime = "1.3.6.1.2.1.1.3.0"
        };

        readonly instrumented attribute int systemUptime
        "The time (in hundredths of a second) since "
        "the network management portion of the system "
        "was last re-initialized.";

But this code is not retrieving any systemUptime value. Do somebody please help here, what went wrong?

-Arun