using a SMP3 pyranometer

Using a SMP3 pyranometer to monitor infrared radiation

The Kipp and Zonen SMP3-V measures the infrared radiation (from 300 to 3000 nm). It is a full modbus device.

connection to a computer using a MOXA uport 1150

On a window desktop, go to the device manager and check that the Moxa works in RS485(2W)

The SMP comes with a 8-wire cable :

• 1 - red : Not used
• 2 - blue : MODBUS GND
• 3 - green : analogue out
• 4 - yellow : MODBUS B+
• 5 - grey - MODBUS A-
• 6 - brown : analogue ground
• 7 - white : VCC (12 ACDC)
• 8 - black : GROUND

Connect the SMP as follow :

Install the Kipp and Zonen Smart Explorer software, and connect to the device

configuration for connection to the Themis RS485 bus

As the Enless radio receiver is the slave number 1 on the Themis RS485 bus, we have to change the SMP3 modbus ID. We can use the following settings :

• modbus ID : 3
• baudrate : 9600
• parity : None
• stop bits : 1

Please note that that factory configuration is :

• modbus ID : 1
• baudrate : 19200
• parity : even
• stop bits : 1

To fix the configuration in the SMP :

• change mode from normal network use to single instrument use
• go to the configuration tab
• press update

Connection to the Themis RS485 bus

Adjust Emonhub configuration :

[[ModbusTCP]]
    Type = EmonModbusTcpInterfacer2
    [[[init_settings]]]
        modbus_IP = 192.168.2.1 # ip address of client to retrieve data from
        modbus_port = 503 # Portclient listens on
        fCode = 3 # optional if using function code 3 (read holding registers) - with fCode = 4, the interfacer will read input registers
    [[[runtimesettings]]]
        nodeIds = 23,24
        pubchannels = ToEmonCMS,
        # time in seconds between checks, This is in addition to emonhub_interfacer.run() sleep time of .01
        interval = 10

In our case, SMP3 is on node 24, whereas node 23 is a standard wireless TRH node

[[24]]
    nodename = SMP3-V
    [[[rx]]]
       names = dev. type,model,net rad.,body temp.
       registers =1,2,7,9
       unitIds = 2
       datacode = H
       scale = 1

modbus registers