Table 6-1: RS-485 register map
Starting register
number
Register
count
Data format
Units
Description
42
2
Float
µV/W/m
2
Sensor sensitivity
47
2
Signed 32 bit integer
Calibration date
7. RS-485 programming
The RS-485 output can be directly read by a MeteoPV, CR6-series, CR1000X-series, or Modbus
RTU RS-485 network. Other Campbell Scientific data loggers can use an MD485 multidrop
interface to read the RS-485 output (refer to the MD485 manual).
A CR6 or CR1000X data logger programmed as a Modbus Master can retrieve the values stored in
the Input Registers. To do this, the CRBasic program requires a
SerialOpen()
instruction
followed by the
ModbusMaster()
instruction.
The
SerialOpen
instruction has the following syntax:
SerialOpen
(ComPort, Baud, Format, TXDelay, BufferSize, Mode)
The
Format
is typically set to logic 1 low; even parity, one stop bit, 8 data bits. The
Mode
parameter should configure the ComPort as RS-485 half-duplex, transparent. The
ModbusMaster()
instruction has the following syntax:
ModbusMaster
(Result, ComPort, Baud, Addr, Function, Variable, Start, Length,
Tries, TimeOut, [ModbusOption])
The
Addr
parameter
must
match
the
sensor
Modbus
address.
To
collect
all
of
the
values,
the
Start
parameter
needs
to
be
1
and
the
Length
parameter
needs
to
correspond
with
the
register
count
(see
).
ModbusOption
is
an
optional
parameter
described
in
the
CRBasic
Editor
Help.
Refer
to
for
more
information.
8.
Analog
ue
programming
The pyranometer outputs a low level voltage that is measured using either the
VoltDiff()
CRBasic instruction or
VoltSE()
CRBasic instruction.
SR05 Second Class Pyranometer with Various Outputs
6
