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UNSUPPORTED FIELDS
The register map reserves register for all combinations of sensors supported by the RainWise stations. Not all will be available on any
one system. Sensors/fields that are not supported can contain the hexadecimal value of 8000. Some fields require the purchase of
additional sensors. The values reported by fields that don't have valid sensors installed should be ignored.
DEVICE SETTINGS
All settings and user selectable options are configured using a set of Modbus registers. These registers are located outside of the
standard SunSpec register block. They do not affect a SunSpec compliant logger's ability to correctly identify and read the PVmet 500.
A terminal emulator program is required to change device settings for use with any other protocol.
MODBUS ADDRESS (REGISTER 200)
The PVmet-500comes with a default Modbus address of 60. The address can be changed by writing to register 200 shown in Table 6.
#
Name
Type
200
1
Modbus Id
int16
Once the address is written the PVmet-500will store the new address in permanent flash memory. The new address will take effect
immediately. The valid address range is 1 to 255.
It is only recommended to change this address if a conflict is anticipated. If the address has been modified and is unknown
it can be discovered by reading only holding register number 200 at Modbus address 250. Be sure to only read a single
register. The PVmet-500will not respond to register read requests other than 200. You cannot write to this register with
address 250. Set your master to read the address reported and then write the desired address to register 200.
IRRADIANCE SENSITIVITY SETTINGS (REGISTERS 202,203,204)
Irradiance sensors have a range of sensitivity calibrations. This can vary from sensor to sensor. In most cases, especially with thermopile
sensors, each sensor will be supplied with a sensitivity constant. This is typically expressed as microVolts per Watt meter squared
-2
(µV/Wm
). The PVmet-500defaults all three sensor inputs to 5.00 µV/Wm
expressed as 500. The sensitivity registers are shown in in
#
Name
201
1
Irradiance_Global_Sensitivity
202
1
Irradiance_Plane_of_Array_Sensitivity
203
1
Irradiance_Other_Sensitivity
Table 6: Device setting Modbus Id
Units
Scale Factor
Contents
-
-
60
Table 7: Device setting registers for solar irradiance sensitivity
Type
Units
uint16
µV/Wm
uint16
µV/Wm
uint16
µV/Wm
R/W
R/W
-2
. Taking the scale factor into account the constant is
Scale Factor
Contents
-2
0.01
500
-2
0.01
500
-2
0.01
500
- 20 -
Description
Modbus device address
R/W
Description
R/W
Sensitivity setting of solar irradiance sensor
R/W
Sensitivity setting of solar irradiance sensor
R/W
Sensitivity setting of solar irradiance sensor
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