Systems and methods for providing status data to a requesting device are disclosed. A request for status data is transmitted from a requesting device to a providing device. The request includes prior values of variables stored at the requesting device. At the providing device, the transmitted prior values are compared with current values of the variables stored at the providing device. Changed variables, which comprise variables for which the current value is different from the prior value, are identified. A variable map is formulated that identifies the changed variables. Current values for the changed variables and variable map are organized into a pre-defined format to form status data. The status data is transmitted to the requesting device.