Model 850

The Model 850 contains 3-axis fluxgate magnetometer and 3-axis accelerometer packages, both are temperature calibrated to operate through the entire operating temperature range of the system. The combination of these two sensor systems enables determination of the toolface, inclination, and azimuth angles of the directional sensor.

The Model 850 transmits the instrument temperature and either the magnetometer and accelerometer outputs or the system orientation angles. The maximum transmission rate is 8 times per second for magnetometer and accelerometer outputs and 4 times per second for orientation angles.

The Model 850 communicates over a serial bidirectional TTL interface. The serial-in and serial-out lines operate at TTL levels and are normally set to operate at 9600 baud with one stop bit and no parity. The user however can change the baud rate by setting bits in the sensor.

Two communication protocols are available, ASCII and binary:

• With the ASCII protocol, the data returned by the Model 850 is transmitted as an ASCII data stream, complete with returns and line feeds, so that it can be easily displayed on a video terminal (provided a TTL to RS-232 conversion is made by the user).
• The binary protocol is used for high speed sensor to computer interchange. In this case, two bytes are sent to request data. The Model 850 then responds with a multibyte data packet containing the desired data plus header and checksum.

The Model 850 can also be configured to either end data when queried or can be run in an “autosend” mode that continuously sends data in ASCII or binary protocol upon power-up.

The Model 850 system is also available in multiple different configurations with custom end caps and electrical interface configurations available.