Casella CEL Nomad portable weather station - Manual (Page 15)

3. OPERATION USING A DIRECT LINK BETWEEN
PC AND NOMAD, VIA FLASHCARDS, CABLE,
GSM MODEM, OR HIGH POWER RADIO
The procedures described in this chapter may be used with any Nomad system
that is connected to the PC by RS 232 cable, connected via a GSM (Global
System for Mobile communications) modem, or connected via a high power
radio link
2
. Cable connection may be temporary when a technician is visiting any
Nomad system in the field, or a permanently connected system.
Assemble the system and deploy the sensors as described in
Chapter 2. When full communication via a high power radio link is required,
supply 24 V DC to the Nomad station. For example use the standard W4/1602/4
Cable (500 m) and 142009C Landline Interface mentioned in Section 9.3.
Once the Nomad system has stored the required data in the Sensus
data logger, the user can visit the System to download data, data can be
downloaded via a permanent RS 232 cable link (when one exists), or
downloaded over a GSM modem or high power radio link with landline power.
Ensure that Online Pro has been installed on the PC and that the
configuration file for the Nomad weather station has also been loaded (see
Chapter 5).
When visiting the Nomad for download, connect the communications
cable from your PC to the RS 232 port on the right hand side of the Sensus unit.
See Chapter 8 for a review of the available communication methods.
3.1 Start Logging
When the Sensus data logger was left running after checking the battery voltage
as described in Section 2.3, it will already be logging (storing) data.
If the battery in-line fuse was removed for transit, or the Sensus data
logger switched off, start logging data to the Sensus as follows.
1. Support the weight of the environmental case door, undo the clips
which hold it shut, then lower the door until the chains support it.
Do not put or hang anything heavy on the lowered door !
2. Replace the in-line fuse if it has been removed.
3. Press key 1 on the Sensus logger (shown in Figure 1).
When sufficient power is available, shown by activity on the display,
the logger will wait one minute before starting to store data at the rate
specified by the active configuration. The default rate stores data at 5
minute intervals.
The Nomad will continue storing data until stopped by the logger keys
or lack of power.
4. Close and re-clip the door of the environmental case.
3.2 Get Stored Data
The Nomad system can store data on-board by logging data into the Sensus
data logger memory or by storing data on CompactFlash cards plugged into the
Sensus data logger.
Operation via Direct Link
Note 2: Because of power constraints, when the Nomad system is powered by the solar panel
and internal battery, it is configured to operate as a semi-passive data transmission
system in the same way as the low power radio link. See chapter 4.
Configuration for full two-way operation with a high power radio link, as described in
this chapter, is possible ONLY when the Nomad system receives its power from a
landline.
Page 15 of 68
NOMAD Portable Weather Station
Users Handbook