Vaisala HMP240 - Manual (Page 26)

HMP240
User's Guide
M210300en
24
5. COMMANDS
As the HMP240 transmitter is a microprocessor based device, its configuration
can be set to correspond to the specific needs of the user. This is done through
commands, either by utilizing the menus on the local display or by giving
commands through the serial interface (see Appendix 1). Most often the
commands are used to change the settings of the two analogue channels.
A limited range of commands can be given by using the three press switches -
up, down and enter - inside the transmitter housing. Four LEDs indicate the
command given with the up and down switches. LED commands can be used
to calibrate the transmitter (both humidity and temperature) or to calibrate the
analogue outputs.
A full range of commands can be given through the display/keypad or through
the RS 232C serial bus. The commands can be used e.g. to select and scale the
outputs, to calibrate the humidity and temperature channels as well as the
analogue outputs and to set the serial interface.
5.1 Commands and security lock jumper
In order to prevent any tampering with the transmitter settings, the transmitter
cannot be calibrated, the analogue outputs set or the analogue output
quantities selected or scaled unless the security lock jumper has been discon-
nected. The commands involved are:
• all LED commands
• display/keypad commands:
Cali ð RH T Ta
Analog outputs
Mode ð Analog outputs ð Mode
Scale
More ð More ð Frost
More ð Frost
• serial commands:
CRH, CT, CTA, FCRH, ACAL; AMODE, ASEL, ASCL, FROST,
FILT
In the following, the description of these functions is preceded with a re-
minder of the security lock jumper:
Disconnect the security lock jumper!