Campbell Scientific PWS100 Present Weather Sensor - Manual (Page 82)

Section 7. Operation
To set the time without the date being altered the following should be used:
TIME hh:mm:ss ↵
7.9.2 Resetting the System
The system is reset by using the RESET command as follows:
RESET ↵
This will terminate all current measurements and reset the system. The time,
date and calibration values will be maintained, but all other user enterable data
are lost and will need to be input again as required.
If a problem is found with the sensor first try power cycling the sensor. A soft
reset is the next level of debugging and should be tried before using a hardware
reset (see switch settings).
7.10 Connecting the PWS100 to a Datalogger
7.10.1 Connections
The PWS100 can be connected to a datalogger using the supplied RS-232 cable
with a null modem between the PWS100 and the datalogger. The connections
should adhere to the EIA232F standard for RS-232 communications. If the
supplied 9 pin D-connector is removed to connect to a device without a
suitable socket for the D-connector then connect using the information supplied
in Table B-1.
Please make sure that the RTS/CTS lines are connected correctly when making
up this cable as no data will be transmitted otherwise. Normally these lines
should be connected together in the PWS enclosure or joined at the end of the
cable, as it is not necessary to use handshaking with a Campbell Scientific
datalogger.
7.10.2 Example Logger Programs
Prior to writing a data logging program whether is be for a Campbell logger or
another system it is important to consider the issue of whether the sensor is to
be set to automatically transmit the data at a given interval and the logger
capture it OR the logging system poll the sensor based upon the loggers
timebase.
The automatic transmission system appears to be easier and may be the only
way to work where several systems need to listen in and pick up data from one
sensor. However, there will always be issues with synchronising the data
transmitted by the sensor and that stored alongside it in the logging system.
The main cause of these problems is the relative time drift between the sensor
and logging system. The simplest issue this causes is the timestamp from the
sensor will drift away from the logger, unless regularly corrected and also the
data output from the sensor will relate to different times in the logger (e.g., the
sensor may output anywhere within the loggers’s minute interval if set to one
minute output interval). More noticeable issues are that, depending on the
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