Vaisala WAC155, User Manual

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Figure 7 Sensor Wiring
1 Anemometer cable ZZ45036
2 Spare gland (for chaining the power and signal wires)
3 Gland for power and signal cables
4 Wind vane cable ZZ45037
3.4.2 Signal Output
The serial wind transmitter WAC155 provides a 2-wire half-duplex RS-485 serial bus for data
interchange. Wind data is provided in standard NMEA 0183 messages. A service connection is
available for configuration and status information.
Several transmitters can share the same RS-485 bus. If there are several transmitters in the
same bus, auto-transmission cannot be enabled, and data must be polled from one sensor at a
time using NMEA query. If you use only one transmitter, you can configure it to automatically
transmit data at selectable intervals.
Each device in the bus has a unique, configurable ID, containing 1 to 5 characters. Alphabetical
characters a - z, A - Z (case-sensitive), and numbers 0 - 9 are accepted.
Typically, only a 4-wire shielded cable is required for the line between WAC155 and the host.
Two of the four wires provide the operating power for the system. The other two wires are for
the RS-485 serial line. Vaisala recommends twisted pair wires for both the power line and the
data line.
Chapter 3 – Installation
17