Using external sensor data

Modern Trimble reference station receivers are capable of requesting data, such as meteorological data or tilt measurements, from multiple external instruments and to pass the data through to the Trimble 4D Control Server system. An active connection to the receiver is necessary.

The sensors and the receivers need to be capable of supporting the "daisy chaining" of multiple instruments on a single serial port. This feature is most often used to support data collection using both meteorological and tilt sensor devices on a single RS232 port. Daisy chaining may be accomplished using custom cabling where the "transmit data" (TXD) RS232 line from one instrument is connected to the "receive data" (RXD) RS232 line of the next instrument. The receiver sends a command to the first instrument in the chain. Each device responds to a specific address. If the command is addressed to the instrument, it sends a measurement response to the next device in the chain. Otherwise, the command is transmitted without modification, and the next device has an opportunity to process it. The receiver receives and logs the response from the last instrument in the chain.

Instruments

See the table for a list of external sensor instruments where responses can be decoded.

Enabling the use of external sensor data

To set up a configuration of parameters and commands to be used for the communication with external sensors, add a GNSS Receiver module with an active connection to the receiver and edit its properties of the External Sensor category.

Alarming for tilt

If the response strings can be decoded, the Alarm Manager module can issue alarms on too high tilt angles, if it is set up appropriately in combination with the GNSS Receiver. Tilt alarming thresholds are specified in the External Sensor category of the GNSS Receiver properties.

Viewing the data

The responses from the sensors received by the GNSS Receiver module are displayed in text style in its Receiving Info module-view. If the GNSS Receiver module has been able to decode the response, numerical meteorological and tilt data are displayed there, too. They are also listed for all such GNSS Receiver modules in the Device Manager External Sensor Info view. The GNSS Receiver Temperture Chart, Humidity Chart, and Pressure Chart views graphically display the history of weather station values, if the module is currently receiving such data.

Storing the data

The external sensor data can be stored at the receiver and for later usage in the system.

• With data logging enabled at the receiver, the response string is saved in binary format in its T01 file.
• With a Storage module added to the GNSS Receiver module, the response string is saved in binary format in the T01 and DAT files. With RINEX storage, you can enable the storage of meteorological files from decoded response strings.