System layout - APA501

Vaisala AviMet Pressure Altimeter System System Description

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Technical description

Vaisala AviMet Pressure Altimeter System is composed of PTB330, HMP155, and WID513. Vaisala Pressure Altimeter Accessory Set APA501 combines these components into a system, which is designed as a simple and small installation nearby the users.

PTB330 is inside the enclosure. You can install the enclosure indoors if mechanical ventilation does not alter the pressure, or outdoors sheltered from direct sunlight (for example, on a north side wall).

Install HMP155 outdoors, roughly 2 meters (6 feet 7 inches) from the ground. HMP155 is typically installed on the wall or on a pole mast.

To ensure reliable communication throughout the installation distances, the system uses RS‑485 connections. For a simple installation, the sensors are powered through WID513 using a combined signal and power cable.

Figure 1. Vaisala AviMet Pressure Altimeter System layout. A standard delivery includes 10‑meter (32‑foot 10‑inch) cables between the enclosure and HMP155 or WID513. For the maximum cable lengths, see the following figure.