Supplying Power To Pwd22; Internal Heaters Without Pwl111 (Default); Internal Heaters With Pwl111 (Optional); Figure 15 Maintenance Cable - Vaisala PWD22 User Manual

User's Guide _______________________________________________________________________
48____________________________________________________________________ M210543EN-B
Figure 15 Maintenance Cable

Supplying Power to PWD22

Power supply can be connected separately for the measurement
electronics and heating. This allows for the battery backup to be
limited to the measurement power supply.
Measurement electronics require 12 VDC ... 50 VDC. All the heaters
can take AC, DC, or rectified AC. Heater voltage dimensions are
specified below.

Internal Heaters without PWL111 (default)

Whenever separate heating power is not available, the measurement
electronics supply of 12 VDC ... 50 VDC must be used to supply the
internal heaters, too. When separate heater power is applied, it can be
used to supply internal heaters.
Choosing whether to use or not separate supply for internal heaters, is
done by jumpers X5 and X8 on PWC Controller/Receiver circuit
board. See section Appendix B, PWC22 Connectors and Jumper
Settings, on page 115. As a default, electronics power supply is used
for heating power.

Internal Heaters with PWL111 (optional)

The heaters for Background Luminance Sensor PWL111 (optional)
are parallel to the PWD22 internal heaters (connector X18 on the
PWC board). PWL111 heaters can only be powered by 12 V or 24 V
or something in-between. If the DC supply is used to power internal
heaters when PWD22 is equipped with PWL111, the DC voltage must
not exceed 28 V (24 V recommended). If the DC voltage is as low as
12 V, the jumpers on the PWL111 board must be set to
12 V to guarantee sufficient heating power.
0309-044