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Serial interface – Vaisala HMT360N User Manual

Page 54

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User's Guide ______________________________________________________________________

52 __________________________________________________________________ M210744EN-C

If there is another channel available, the display shifts to the scaling
menu of Ch 2. You can now scale the analog outputs for the Ch 2 in the
same way as described above.

Press button C to exit the display command mode or continue by
selecting the output quantities. This menu starts automatically after the
scaling menu only if the output selection DIP switches are on the
position special (all up) from the beginning.

Serial Interface

Use the serial interface for calibration and testing purposes in safe areas
only. Always use the serial interface cable (optional accessory, Vaisala
order code: 25905ZZ). Connect one end of the cable to the serial port of
your computer and the other to the connector marked "RS232C" on the
electronics unit of the transmitter (see

Figure 5 on page 23

).

NOTE

Remember to restore the DIP switch settings.

WARNING

The serial interface MUST NOT be used in hazardous areas.

NOTE

With serial communication the current consumption increases
approximately to 7 mA and the transmitter is not able to operate with
4 mA. Therefore, it is recommended to use serial communication only
temporarily for changing settings or for calibrating the transmitter in a
safe area. With serial port, the minimum supply voltage is 15 VDC.

NOTE

The transmitter incorporates a serial interface detector. However, not
all terminals or PC serial ports (for example, optoisolated or ports not
meeting RS232C standards) recognize this standard. If the
communication is not possible via a serial interface, use a forced
activation by pressing simultaneously buttons Up and E on the
transmitter cover. To deactivate the forced activation, press these
buttons again or reset the transmitter. If the transmitter does not
receive any commands for half an hour, it automatically closes the
serial communication.