Campbell Scientific CS125 Present Weather Sensor - Manual (Page 35)

User Guide
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14 Serial port protocol 0-1 Selects the physical serial interface
0 = RS232 mode
1 = RS485 mode 0
15 Averaging period 1 or 10 The period of time that the visibility value should
be averaged over. Either one minute or ten. 1
16 Sample timing 1-60 Used to define the time interval between sampling
the volume. It is recommended that this value is
left at one except when very low power demands
are needed. For example:
1 = Sample every second
2 = Sample one second in every two
3 = Sample one second in every three etc. 1
17 Dew heater override 0-1 0 = Allow the CS125 to automatically control the
dew heaters
1 = Turn the dew heaters off 0
18 Hood heater override
(1)
0-1 0 = Allow the CS125 to automatically control the
hood heaters
1 = Turn the hood heaters off 0
19 Dirty window
compensation 0-1 0 = No compensation applied
1 = Compensation for dirt on lenses applied.
The CS125 will compensate for up to 10% signal
loss due to dirt per lens. 0
20 Use CRC 0-1 0 = Disable command line CRC checking (2)
1 = Enable command line CRC checking
Note: this does not affect communications via
DevConfig or terminal emulator.
0
21 Sensor power down
voltage 7-30 PSU Input voltage level below which the CS125
will enter low power mode. This is usually used to
protect batteries. 7.0
22 Relative humidity
threshold 1-99 Threshold at which the CS125 will define
obscuration as liquid or dry if a CS215 is fitted. 80%
(1) Hood heater override needs to be set to `1’ (off) when either no hood heaters are installed or
the hood heaters have no power connected to them. This will save power as the relay is not
enabled at low temperatures in this mode.
(2) If disabled the sensor does not check the validity of received data against the checksum sent.
It is, however, recommended that checksum checking is enabled to remove any chance of the
CS125 being configured incorrectly by accident.
14. Command line mode
The command line interface is broken down into three major commands. These
are GET, SET and POLL. The GET command is used to request all current user
settable values from the CS125. The SET commands sets user settable values and
the POLL command is used to request the current visibility and/or alarm
conditions from the sensor.
The CS125 can be configured to expect any commands sent to it to include a valid
checksum. For simple commands, e.g. GET and POLL, fixed value checksums
can be used (see the example programs). For more complex SET commands the
checksum needs to be calculated (see Appendix B). The use of the checksum is
disabled by default. It is recommended that the checksum functionality is enabled
where possible, especially when long cable runs are used, or in electronically
noisy environments.