WHEATBRIDGE :: Device Interpreters

DRIVERS AND DEVICE INTERPRETERS

While usually it is in the best interests of a device manufacturer to build a driver for their hardware, that is unfortunately not always the case. There is a tendency among manufacturers to build their own data displays, and they expect that display to be used. Most systems don't have the luxury of having a computer monitor for each and every system they have, so sometimes it is necessary to write a driver or driver interface.

As we discuss elsewhere on this website, there are many types and kinds of device interpreters, but among the more important are SNMP, which stands for Simple Network Management Protocol. There is nothing simple about SNMP. It is a family of protocols that provide a means for monitoring and controlling networked devices. SNMP devices are usually referred to as "smart" devices. Using SNMP makes device management more involved and its installation more complex.

SNMP is nevertheless very powerful and it permits active management tasks such as modifying and applying a new configuration through remote modification of variables, which are organized in hierarchies. These hierarchies and other metadata (such as type and description of the variable), are described by Management Information Bases (MIBs). Usually these MIB files are based on standards, such is NTCIP. We have experience building a number of drivers for these types of devices, such as matrix or variable message signs, encoders and decoders, and switches. Devices of these kinds have hundreds of configuration options.

We also have experience developing data collection drivers for less complex proprietary systems, such as camera pan-tilt-zoom-and-focus. We have written camera device drivers for RS485 (and ethernet IP to Serial) for Pelco D, Pelco P,AD422, Fastrax, DynaColor, JVC, Panasonic (STX/ETX) protocols.

Other device protocols allow an application to communicate with the sensor over a dedicated TCP/IP link and simple ASCII string transactions. They allow for the transfer of data (per time-interval), event data, and other data strings as well as the alteration of some sensor configuration settings, such as sensor clock time, duration of time or interval for data aggregation, baud rate, reconnect retries, inter-message delays, HDLC groups and addresses, host address, names, and data classification.