Modbus profile with SunSpec Data Types

Modbus profile with SunSpec Data Types - Printable Version

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Modbus profile with SunSpec Data Types - winamp - 03.07.2018

Hi all,

I need to create a Modbus profile for a PV inverter with Sunspec Data Types. They are documented at https://www.sma.de/fileadmin/content/landingpages/pl/FAQ/SunSpec_Modbus-TI-en-15.pdf on page 13-14. The most registers have the dt int or uint and can be easily integrated into the Modbus profile. But I also need some registers with data types that are not in the LM Modbus profile description like acc32, bitfield16, enum16 or string. I already read that the string format is not supported in profile, so my question is, if the other three data types can be integrated?

For example there is a register called "Battery Type" with dt enum16. Then there are defined types for values from 0 to 10 like 0: Unknown, 1: Lithium-Ion, ...
Can I set the register in the Modbus profile as dt uint16 and write these types under value_custom? Same question applies to the dt bitfield16, because there are also costum values.

I can't do a RTU read test right now so I'm thankful for any help.

Best Regards

RE: Modbus profile with SunSpec Data Types - AEK - 06.07.2018

(03.07.2018, 12:30)winam Wrote: For example there is a register called "Battery Type" with dt enum16. Then there are defined types for values from 0 to 10 like 0: Unknown, 1: Lithium-Ion, ...
Can I set the register in the Modbus profile as dt uint16 and write these types under value_custom?

Hi, I think that it is the best way
try to do like this

Code:
{
      "name": "Mode",
      "bus_datatype": "uint8",
      "datatype": "int16",
      "type": "register",
      "address": 3,
      "writable": 1,
      "Value_custom": {
        "0": "Auto",
        "1": "Heat",
        "2": "Fan",
        "3": "Cool",
        "4": "Dry"
      }
    },

(03.07.2018, 12:30)winamp Wrote: Same question applies to the dt bitfield16, because there are also costum values.

here you need valuebitmask

for bitfield16 exaple:

Code:
{
      "name": "bitfield16 bit 0",
      "bus_datatype": "bool",
      "type": "register",
      "datatype": "uint16",
      "address": 50002,
      "value_bitmask": "1",
      "value_custom": {
        "0": "no err",
        "1": "err"
      }
    },
    {
      "name": "bitfield16 bit 1",
      "bus_datatype": "bool",
      "type": "register",
      "datatype": "uint16",
      "address": 50002,
      "value_bitmask": "2",
      "value_custom": {
        "0": "no err",
        "1": "err"
      }
    },
    {
      "name": "bitfield16 bit 2",
      "bus_datatype": "bool",
      "type": "register",
      "datatype": "uint16",
      "address": 50002,
      "value_bitmask": "4",
      "value_custom": {
      "0": "no err",
      "1": "err"
     }
    },

value bitmask = 2^N
N - bit number (from 0 to 15)

for bitfield32 example:

Code:
{
      "name": "bitfield32 bit 0",
      "bus_datatype": "bool",
      "type": "register",
      "datatype": "uint16",
      "read_swap": "b",
      "address": 50002,
      "value_bitmask": "1",
      "value_custom": {
        "0": "no err",
        "1": "err"
      }
    },
    {
      "name": "bitfield32 bit 1",
      "bus_datatype": "bool",
      "type": "register",
      "datatype": "uint16",
      "read_swap": "b",
      "address": 50002,
      "value_bitmask": "2",
      "value_custom": {
        "0": "no err",
        "1": "err"
      }
    },

there is new feald - "read_swap"

Code:
read_swap

Boolean/String
Swap byte/word order during conversion (endianness). Default value is word (2-byte) swap.
Possible string values:

Code:
n

(no swap),

Code:
w

(word swap),

Code:
b

(byte swap),

Code:
bw

(byte and word swap)
Example:
no swap: 0xABCD
word swap: 0xCDAB
byte swap: 0xBADC
byte and word swap: 0xDCBA