LM as a Modbus slave : number of slaves

[SigmaTec]

First, check the Error log for any errors.
You can use this test script for reading from local TCP slave with port 502 (check Logs tab for the read result or any errors):

Code:

require('luamodbus')

mb = luamodbus.tcp()
mb:open('127.0.0.1', 502)
res, err = mb:connect()

if res then
  val, err = mb:readregistervalue(3204, 'int64', 'b')
 
  if val then
    log('read ok', val)
  else
    log('read failed', err)
  end
else
  log('connect failed', err)
end

mb:close()

Result : 
* arg: 1
  * string: connect failed
* arg: 2
  * string: Connection refused

But to be sure we are on the same subject :
my deal is to use LM as Modbus slave in order to write in it some registers which will be read by a master.