LM as a Modbus slave : number of slaves

[SigmaTec]

In TCP mode you can have multiple slave scripts but they must use different ports (e.g. 502, 503 etc). In RTU mode only one slave is supported at the moment.

Hi Admin,

Ok, I understood the principle. But how to decompose the cyclic script which sets the port (eg. 502) and the slave id (eg. 2) into several slave scripts with different ports?

How will the mbetregisters() function find its way?

Code:

-- modbus init cyclic script if not mb then require('luamodbus') -->>>>>>>>>Modbus slave setting<<<<<<<<<<<<<<<<<<<<<<<<   ------------------------------------------------------ -- Pour Modbus RTU ------------------------------------------------------ --mb = luamodbus.rtu() --mb:open('/dev/RS485', 19200, 'E', 8, 1, 'H') --mb:connect() ------------------------------------------------------ -- Pour Modbus TCP ------------------------------------------------------ mb = luamodbus.tcp() mb:open('0.0.0.0', 502) ------------------------------------------------------  -->>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<    -- slave id mb:setslave(2)   -- init slave storage for coils, discrete inputs, holding registers and input registers mb:setmapping(1, 1, 3300, 1)   --***************************************************** -- >>>>>>>>>>>Coil write callback<<<<<<<<<<<<<<<<<<<<<< mb:setwritecoilcb(function(coil, value) if coil == 0 then grp.write('0/0/12', value, dt.bool) else alert('coil: %d = %s', coil, tostring(value)) end end) --***************************************************** -->>>>>>>>>>>Register write callback<<<<<<<<<<<<<<<<<<< mb:setwriteregistercb(function(register, value) if register == 0 then -- send value limited to 0..100 grp.write('0/0/13', math.min(100, value), dt.scale) else alert('register: %d = %d', register, value) end end) --***************************************************** end -- server part init if not server then log("Modbus slave handler (cyclic) : IN...server init") require('rpc') -- incoming data handler local handler = function(request) local fn, res fn = tostring(request.fn) if not mb[ fn ] then return { nil, 'unknown function ' .. fn } end if type(request.params) == 'table' then table.insert(request.params, 1, mb) res = { mb[ fn ](unpack(request.params)) } else res = { mb[ fn ](mb) } end return res end server = rpc.server('127.0.0.1', 28002, 'mbproxy', handler, 0.01) log("Modbus slave handler (cyclic) : OUT...handleslave = ") end res, err = mb:handleslave() res, err = server:step()

Thank's for your time....