Pvmet-500Holding Registers; Scaling; Rainfall Operation - RainWise PVmet 500 Series User Manual

Field Address Block
Type Offset Offset
Header 0
Header 1
Fixed
2 0
Block
Fixed
3 1
Block
Fixed
4 2
Block
Fixed
5 3
Block
Fixed
6 4
Block
Fixed
7 5
Block
Fixed
8 6
Block
Fixed
9 7
Block
Fixed
10 8
Block
Fixed
11 9
Block
Fixed
12 10
Block

PVMET-500HOLDING REGISTERS

A complete table of all the SunSpec holding registers is shown in the appendix.
The PVmet 500's first register C SunSpec ID is located at 40,001. This document assumes base 1 addressing is being used. If the host
system uses base 0 addressing, decrement the starting register values shown by 1.
All registers in the SunSpec Register map are read-only. Use the Modbus 03 command to access the data. Do not attempt to read
beyond the specified map, the PVmet-500may not respond.

SCALING

Holding registers only support integer values (no decimal points). To improve resolution many of the measured values are scaled up by
a factor of 10 or 100. The Modbus master must convert the data point to a floating-point variable and multiply by the "scale factor"
indicated in the table below. For example, a temperature of 25.3°C will be reported as 253. Multiplying by the scale factor of 0.1 results
in a final value of 25.3.

RAINFALL OPERATION

The SunSpec specification for rainfall mandates that the rainfall register 40 077 will reset after each Modbus poll. To effectively use
this parameter, the host system must implement a separate running rainfall counter variable in the host system. The contents of the
rainfall register must then be added to this variable on EVERY read. As this may be difficult to implement on many systems a second
register has been provided outside the SunSpec register map. The separately provided value is a running counter in mm.
Table 5: SunSpec model 307, base meteorological
Size Name Label
1 ID Base Met
1 L
Ambient
1 TmpAmb
Temperature
Relative
1 RH
Humidity
Barometric
1 Pres
Pressure
1 WndSpd Wind Speed
Wind
1 WndDir
Direction
1 Rain Rainfall
1 Snw Snow Depth
Precipitation
1 PPT
Type
1 ElecFld Electric Field
Surface
1 SurWet
Wetness
1 SoilWet Soil Wetness
Value Type Unit SF
307 uint16
11 uint16
int16 C -1
int16 Pct
int16 HPa
int16 m/s
int16 deg
int16 mm
int16 mm
int16
int16 Vm
int16 kΩ
int16 Pct
- 19 -
R/W Description
R Base Meteorological Model
R Model Length
R
R
R
R
R
R
R
Precipitation Type (WMO
R 4680 SYNOP code
reference)
R
R
R
Notes
This model
supersedes
model 301