Campbell CR200, Instruction Manual

Page: 120 / 212

Section 11. Programming Resource Library
110
Either the output array or the input array or both can be specified as 0 meaning
no data flow in the corresponding direction.
The HostAddr parameter is the PakBus Address of the master of the network,
the destination of the sensor’s data. The RouterAddr is the PakBus Address of a
router if the distance is too far to reach the Host directly. Typically a router will
not be present so this address with be identical to the HostAddr. If it is 0, then
the system will automatically find a neighbor it can route through.
All communication with the host datalogger (CR800, CR1000 or CR3000) takes
place through the SendGetData() instruction. When SendGetData() is included
in the CR200 CRBASIC program, the CR200 calls the host approximately every
60 seconds with a random time into interval setting to establish the first
connection. At first connection, the CR200 sends a variable array to the host,
retrieves a variable array from the host, and retrieves a call time slot and a clock
synchronization setting. Thereafter, the CR200 calls at the appointed time slot.
11.2 Radio Power Minimization
Power settings on the CR200(X) radio are used to optimize the current drain of
the system. The radio can be set to be always on, power up once a second or
every 8 seconds, or be turned on by the CR200(X) program. When the status
table field RF_ForceOn is set true under program control, the radio is on only as
long as necessary for data transmission and receiving. This provides the lowest
power usage by the radio.
RF_ForceOn can be controlled with table access syntax
(SetStatus(Rf_ForceOn,1) for example) or it is controlled by the instruction
SendGetData() as shown in the following
example p. 111.
A CR1000 datalogger with PakBus address 2 and a RF401 radio is configured
as the “master”. It sends a Network() command every 5 minutes to synchronize
the radio transmission. A CR206X datalogger with PakBus address 3 measures
its sensors every 15 minutes and runs a countdown using TimeUntilTransmit().
When the countdown reaches zero, the CR206X powers its radio and transmits
data to the CR1000 as well as receiving the CR1000 battery voltage.
The radio address and hop sequence of the CR206X must match the same
settings in the RF401.