Power supplies - WXT530

WXT530 Series User Guide

Document code
M211840EN
Revision
F
Language
English (United States)
Product
WXT530
Document type
User guide
WXT530 and the cable must be protected with a fuse or a circuit breaker from the supply side. A fuse or a circuit breaker protects the cable from overheating if there is a short circuit in the cabling.

The maximum size for the fuse or circuit breaker is 2 A. 1.6 A is also enough for guaranteed operation. Over current limitation or protection can also be built into the power supply. This limitation applies to Vaisala cables with 0. 25 mm2 conductors. The minimum conductor cross section area is 0,25 mm2 for WXT530 series instrument with heating.

The minimum consumption graph is for SDI-12 standby mode.

Figure 1. Average operational current consumption (with 4Hz wind sensor sampling)

The input power supply must be capable of delivering 60 mA (at 12 V) or 100 mA (at 6 V) instant current spikes with duration of 30 ms. These are drawn by the wind sensor (whenever enabled) at 4 Hz rate, which is the default value for wind sampling. Wind sampling at 2 Hz and 1 Hz rate is also available.

Because wind measurement is the most consuming operation in the system, the average current consumption decreases almost in proportion to the sampling rate.

Typically, the average consumption is less than 10 mA. The higher the voltage, the lower the current.

Heating voltage Vh+ (one of the following two alternatives):

  • 12 … 24 V DC (−10 % … + 30 %)
  • 12 … 17 V ACrms (−10 % … +30 %)

The typical DC voltage ranges are:

  • 12 V DC ± 20 % (max 1.1 A)
  • 24 V DC ± 20 % (max 0.6 A)

Nominally at 15.7 V heating voltage level, the transmitters automatically change the heating element combination to reduce instant current. The input resistance (Rin) is radically increased with voltages above 16 V as shown in the following graph. The average (5s) power does not depend on the input voltage.

The recommended range for AC is:

  • 12 … 17 VACrms (−10 % … +30 %) max 1.1 A for AC
Figure 2. Heating instant current and power vs Vh (WXT536, WXT535, WXT533, and WXT532)
Figure 3. Heating instant current and power vs Vh (WXT531)

The power supply must meet the values shown above.

WARNING Make sure that you connect only de-energized wires.
CAUTION To avoid exceeding the maximum ratings in any condition, the voltages must be checked with no load at the power supply output.