AHU MODBUS TCP VALUE

[Elmyran]

Hi, I try to connect to Schneider-electric Homelynx and get the airflow from an IVP AHU ventilation unit with a climactix controller.
I need to compare two values in order to control a mixing valve.
The valve opens and closes until the two values are as equal as possible.
The value is to be retrieved from a Holding register with the address 4x0055 and 4x0056.
But unfortunately I do not get any values, it seems that it does not connect or I have typed the wrong code to get the air value correctly.

Code:

require('luamodbus')
if not mb then
   mb = luamodbus.tcp()
   mb:open('192.168.201.53')
   mb:connect()
end
mb:setdebug(true)
openvalue =  grp.getvalue('6/3/1')

tfvalue = mb:readinputregisters(54)
ffvalue = mb:readinputregisters(55)
mb:close()
if tfvalue > ffvalue then
 if openvalue < 220 then
   openvalue = openvalue + 25
 end
end
if ffvalue < ffvalue then
 if openvalue > 25 then
   openvalue = openvalue - 25
 end
end

grp.write('6/3/1', openvalue)

I would be very grateful if you can help me with this problem
/Tommy