Pwh111 Hood Heaters; Communication Options; Serial Communication Settings; Serial Transmission Rs-232 - Vaisala PWD22/52 User Manual

USER'S GUIDE____________________________________________________________________
38 __________________________________________________________________ M210543EN-E

PWH111 Hood Heaters

A separate heating power of 24 V must be applied when using hood
heaters . They use 30 W each, which is 60 W altogether.

Communication Options

PWD22/52 has one serial line with two interfaces. The two-wire RS-485
is intended to be the standard interface. The PWD22/52 software is
designed to allow the RS-232 interface to be used as a service line, when
the RS-485 interface is connected to the host computer.
Usually, PWD22/52 waits for input from both the RS-232 and RS-485
interfaces. Any character from the RS-232 interface disables the RS-485
communication for 10 seconds or until the line is closed by the operator.
Automatic messages are sent to both interfaces along with the messages
polled from the RS-485 interface.

Serial Communication Settings

The default settings of the serial communications port are as follows:
- 9600 baud
- Even parity
- 7 data bits
- 1 stop bit

Serial Transmission RS-232

For the RS-232 communication connect the PWD22/52 signal wires to:
- YEL
- GRN
- GRY
Vaisala recommendation for the maximum length of the RS-232 cable is
50 m. Usually, the RS-232 connection can be used with distances up to
100 m without problems but that cannot be guaranteed.
to PC 3/9: TxD RS-232
to PC 2/9: RxD RS-232
to PC 5/9: GND