Modbus TCP Polling Delay

[manos@dynamitec]

If you want quick polling you need to use one resident script per each connection because Modbus mapper can only poll one TCP device at a time.
Use this example as a starting point. The connection is kept open between requests. Multiple registers are read at once to speed things up.

Code:

if not mb then
  require('luamodbus')
  mb = luamodbus.tcp()
  mb:open('192.168.0.9')
 
  res, err = mb:connect()
  if not res then
    mb:close()
    mb = nil
    log('connect failed', err)
  end
end

if mb then
  v1, v2, v3 = mb:readregisters(10, 3)

  if v1 ~= nil then
    grp.checkupdate('1/1/1', v1)
    grp.checkupdate('1/1/2', v2)
    grp.checkupdate('1/1/3', v3)
  else
    mb:close()
    mb = nil
    log('read failed', v2)
  end
end

Thank you admin, this sounds very interesting. What is the correct sleep interval for this resident script? If I set to 1sec is this going to poll data every 1sec from the slave?
Where can I define the registers I would like to read? I need register 0,1,2 and is it also possible to write to those register the value of the knx object when its changed? So in the end a bi-directional communication with the touch panel over modbus IP.

Until now I was using the following profile with mapped knx objects and worked in both directions. The only issue was the delay.

Code:

{
  "manufacturer": "Pro-Face",
  "description": "Touch Panel GP4301-T GM Blok 02->10 ",
  "mapping": [
    { "name": "Zone 1 On/Off", "bus_datatype": "1001", "type": "coil", "address": 0, "writable": 1, "write_only": 0 },
    { "name": "Zone 2 On/Off", "bus_datatype": "1001", "type": "coil", "address": 1, "writable": 1, "write_only": 0 },
    { "name": "Zone 3 On/Off", "bus_datatype": "1001", "type": "coil", "address": 2, "writable": 1, "write_only": 0 }
  ]
}