LM as a Modbus slave : number of slaves

[admin]

If you only need read-only values on the modbus side you can simply periodically update the register values in the resident script itself. Modify register mapping in updateregisters() as needed. Each script must use a unique port (502, 503 etc).

Code:

if not mb then
  require('luamodbus')
  mb = luamodbus.tcp()

  mb:open('0.0.0.0', 502)
  mb:setslave(2)

  function setint64(grpaddr, regaddr)
    local value = grp.getvalue(grpaddr) or 0
    local raw = knxdatatype.encode(value, dt.int64).dataraw
    local r1 = raw:byte(2) * 0x100 + raw:byte(1)
    local r2 = raw:byte(4) * 0x100 + raw:byte(3)
    local r3 = raw:byte(6) * 0x100 + raw:byte(5)
    local r4 = raw:byte(8) * 0x100 + raw:byte(7)

    mb:setregisters(regaddr, r4, r3, r2, r1)
  end

  function updateregisters()
    setint64('32/1/1', 3204)
  end

  mb:setmapping(0, 0, 3300, 0)
  updateregisters()

  prev = os.time()
end

mb:handleslave()

curr = os.time()
if curr ~= prev then
  updateregisters()
  prev = curr
end