LM as modbus slave

[gdimaria]

Hi, 

I have to set LM as modbus slave to a master modbus device who must be able to read and write on KNX objects.

How should I proceed?

Thanks

Peppe

[admin]

https://kb.logicmachine.net/integration/...tcp-slave/

[gdimaria]

I followed the instructions, but testing with the modbus tool, it times out and does not read the registers. 

I attach the resident script and the mbslave library that I made.

MODBUS RTU SLAVE resident script 

Code:

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require('user.mbslave') local mb = require('user.mbslave') local mbrtu = require('luamodbus').rtu() mbrtu:open('/dev/RS485-1', 9600, 'E', 8, 1, 'H') mbrtu:connect() mbrtu:setslave('1') -- '*' handles multiple RTU slave IDs mb.setmapping({   [1] = {       coils = {       [1] = '2/1/11', -- stato on/off       [4] = '2/1/14', -- stato set %     },     registers = {       [0] = '2/1/10', -- comando on/off      -- [1] = '2/1/11', -- stato on/off       [3] = '2/1/13', -- set %      -- [4] = '2/1/14', -- stato set %     }   } }) mb.setswap('w') mb.setfloat16precision(2) while true do   mb.rtuhandler(mbrtu) end

user.mbslave

Code:

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local _M = {} local byteswap, wordswap local f16mult = 1 local mapping = {} local exception = {} local reply = {} local fncodes = {   [1] = 'readcoils',   [2] = 'readdiscreteinputs',   [3] = 'readregisters',   [4] = 'readinputregisters',   [5] = 'writecoil',   [6] = 'writeregister',   [15] = 'writecoils',   [16] = 'writeregisters', } local mapfncodes = {   [1] = 'coils',   [2] = 'discreteinputs',   [3] = 'registers',   [4] = 'inputregisters',   [5] = 'coils',   [6] = 'registers',   [15] = 'coils',   [16] = 'registers', } local dtlens = {   [ dt.bool ] = 1,   [ dt.bit4 ] = 1,   [ dt.int8 ] = 1,   [ dt.uint8 ] = 1,   [ dt.int16 ] = 1,   [ dt.uint16 ] = 1,   [ dt.float16 ] = 1,   [ dt.int32 ] = 2,   [ dt.uint32 ] = 2,   [ dt.float32 ] = 2,   [ dt.int64 ] = 4, } local maxpdu = 253 local maxaddr = 0x10000 local coilon = 0xFF00 local limits = {   readbits = 2000,   writebits = 1968,   readregisters = 125,   writeregisters = 123, } local excodes = {   illegalfunction = 1,   illegaldataaddress = 2,   illegaldatavalue = 3,   serverdevicefailure = 4,   acknowledge = 5,   serverdevicebusy = 6,   negativeacknowledge = 7,   memoryparityerror = 8,   gatewaypathunavailable = 10,   gatewaytargetdevicefailed = 11, } local handlers = {} local function touint8(buf, off)   return buf:byte(off) end local function touint16(buf, off, swap)   local b1, b2 = buf:byte(off, off + 1)   if swap then     b1, b2 = b2, b1   end   return b1 * 0x100 + b2 end local function getmapping(slaveid, fncode)   local mapfncode = mapfncodes[ fncode ]   local slave = mapping[ slaveid ]   if not slave then     slave = mapping['*']   end   if slave then     return slave[ mapfncode ]   end end local function readbits(slaveid, fncode, data)   if #data ~= 4 then     return   end   local addr = touint16(data, 1)   local count = touint16(data, 3)   if count == 0 or count > limits.readbits then     return excodes.illegaldataaddress   elseif (addr + count) > maxaddr then     return excodes.illegaldataaddress   end   local map = getmapping(slaveid, fncode)   if not map then     return excodes.illegaldataaddress   end   local res = {}   local bits, byte = 0, 0   for i = 0, (count - 1) do     local mapaddr = map[ addr + i ]     if mapaddr then       local bval = grp.getvalue(mapaddr)       if toboolean(bval) then         byte = byte + bit.lshift(1, bits)       end     end     bits = bits + 1     if bits == 8 then       res[ #res + 1 ] = string.char(byte)       bits, byte = 0, 0     end   end   if bits ~= 0 then     res[ #res + 1 ] = string.char(byte)   end   return string.char(#res) .. table.concat(res) end local zeroreg = string.char(0, 0) local function readvalue(res, value, dpt)   if dpt == dt.float16 then     value = value * f16mult     dpt = dt.int16   end   local enc = busdatatype.encode(value, dpt)   if not enc.dataraw then     return   end   local raw = enc.dataraw   if #raw % 2 == 1 then     raw = string.char(0) .. raw   end   local words = #raw / 2   local offset = #res   for i = 1, words do     local word = raw:sub(i * 2 - 1, i * 2)     if byteswap then       word = word:sub(2, 2) .. word:sub(1, 1)     end     if wordswap then       res[ offset + i ] = word     else       res[ offset + 1 + words - i ] = word     end   end   return true end local function readregisters(slaveid, fncode, data)   if #data ~= 4 then     return   end   local addr = touint16(data, 1)   local count = touint16(data, 3)   if count == 0 or count > limits.readregisters then     return excodes.illegaldataaddress   elseif (addr + count) > maxaddr then     return excodes.illegaldataaddress   end   local map = getmapping(slaveid, fncode)   if not map then     return excodes.illegaldataaddress   end   local res = {}   local max = count - 1   while #res <= max do     local mapobj = map[ addr + #res ]     local success     if mapobj then       local value = grp.getvalue(mapobj.address)       if type(value) == 'boolean' then         value = value and 1 or 0       end       if type(value) ~= 'number' then         alert('invalid value ' .. mapobj.address .. ' ' .. tostring(value))         value = 0       end       success = readvalue(res, value, mapobj.dpt)     end     if not success then       res[ #res + 1 ] = zeroreg     end   end   if #res ~= count then     return excodes.illegaldataaddress   end   return string.char(count * 2) .. table.concat(res) end local function writevalue(obj, data, offset)   local words = obj.len   local len = words * 2   local raw = data:sub(offset, offset + len - 1)   if #raw < len then     return   end   local buf = {}   for i = 1, words do     local word = touint16(raw, i * 2 - 1, byteswap)     local hex = string.format('%04X', word)     if wordswap then       buf[ #buf + 1 ] = hex     else       table.insert(buf, 1, hex)     end   end   local hexval = table.concat(buf)   local dpt = obj.dpt == dt.float16 and dt.int16 or obj.dpt   local value = busdatatype.decode(hexval, dpt)   if obj.dpt == dt.float16 then     value = value / f16mult   end   grp.write(obj.address, value) end handlers.readcoils = readbits handlers.readdiscreteinputs = readbits handlers.readregisters = readregisters handlers.readinputregisters = readregisters handlers.writecoil = function(slaveid, fncode, data)   if #data ~= 4 then     return   end   local addr = touint16(data, 1)   local map = getmapping(slaveid, fncode)   if not map or not map[ addr ] then     return excodes.illegaldataaddress   end   local bval = touint16(data, 3) == coilon   grp.write(map[ addr ], bval, dt.bool)   return data end handlers.writeregister = function(slaveid, fncode, data)   if #data ~= 4 then     return   end   local addr = touint16(data, 1)   local map = getmapping(slaveid, fncode)   if not map or not map[ addr ] then     return excodes.illegaldataaddress   end   local mapobj = map[ addr ]   if mapobj.len ~= 1 then     return excodes.illegaldataaddress   end   writevalue(mapobj, data, 3)   return data end handlers.writecoils = function(slaveid, fncode, data)   if #data < 5 then     return   end   local addr = touint16(data, 1)   local count = touint16(data, 3)   local bytes = touint8(data, 5)   if #data ~= (bytes + 5) then     return   end   if count == 0 or count > limits.writebits or bytes ~= math.ceil(count / 8) then     return excodes.illegaldataaddress   end   local map = getmapping(slaveid, fncode)   if not map then     return excodes.illegaldataaddress   end   local offset = 6   local byte = data:byte(offset)   local bits = 0   for i = 0, (count - 1) do     local bval = bit.band(bit.rshift(byte, bits), 1)     local mapaddr = map[ addr + i ]     if mapaddr then       grp.write(mapaddr, bval, dt.bool)     end     bits = bits + 1     if bits == 8 then       bits = 0       offset = offset + 1       byte = data:byte(offset)     end   end   return data:sub(1, 4) end handlers.writeregisters = function(slaveid, fncode, data)   if #data < 5 then     return   end   local addr = touint16(data, 1)   local count = touint16(data, 3)   local bytes = touint8(data, 5)   if #data ~= (bytes + 5) then     return   end   if count == 0 or count > limits.writeregisters or bytes ~= count * 2 then     return excodes.illegaldataaddress   end   local map = getmapping(slaveid, fncode)   if not map then     return excodes.illegaldataaddress   end   for i = 0, (count - 1) do     local mapobj = map[ addr + i ]     if mapobj and not mapobj.readonly then       local offset = 6 + i * 2       writevalue(mapobj, data, offset)     end   end   return data:sub(1, 4) end exception.tcp = function(sock, hdr, excode)   local fncode = bit.bor(0x80, hdr:byte(8))   local resp = hdr:sub(1, 4) ..     string.char(0, 3) ..     hdr:sub(7, 7) ..     string.char(fncode, excode)   return sock:send(resp) end exception.rtu = function(mbrtu, hdr, excode)   local fncode = bit.bor(0x80, hdr:byte(2))   local resp = hdr:sub(1, 1) ..     string.char(fncode, excode)   return mbrtu:send(resp) end reply.tcp = function(sock, hdr, data)   local resp = hdr:sub(1, 4) ..     string.char(0, #data + 2) ..     hdr:sub(7, 8) .. data   return sock:send(resp) end reply.rtu = function(mbrtu, hdr, data)   local resp = hdr:sub(1, 2) .. data   return mbrtu:send(resp) end local function handler(mode, ctx, hdr, data)   local slaveid, fncode = hdr:byte(#hdr - 1, #hdr)   local fnname = fncodes[ fncode ]   if not fnname then     return exception[ mode ](ctx, hdr, excodes.illegalfunction)   end   local res = handlers[ fnname ](slaveid, fncode, data)   if type(res) == 'number' then     return exception[ mode ](ctx, hdr, res)   elseif type(res) == 'string' then     return reply[ mode ](ctx, hdr, res)   end end _M.tcphandler = function(sock)   local hdr, err = sock:receive(8)   if not hdr then     return nil, err   end   local len = touint16(hdr, 5) - 2   local data   if len <= 0 or len > maxpdu then     err = 'protocol error'   else     data, err = sock:receive(len)   end   if not data then     return nil, err   end   return handler('tcp', sock, hdr, data) end _M.rtuhandler = function(mbrtu)   local data, err = mbrtu:receive()   if not data then     return nil, err   end   local slaveid = data:byte(1)   if not mapping[ slaveid ] then     return   end   return handler('rtu', mbrtu, data:sub(1, 2), data:sub(3, #data - 2)) end _M.setswap = function(swap)   byteswap = swap:find('b') ~= nil   wordswap = swap:find('w') ~= nil end _M.setfloat16precision = function(prec)   prec = tonumber(prec) or 0   f16mult = math.pow(10, prec) end local function initobject(obj, dbobj)   local dpt = obj.datatype or dbobj.datatype   if type(dpt) == 'string' then     dpt = dt[ dpt ] or 0   end   if type(dpt) == 'number' and dpt >= 1000 then     dpt = math.floor(dpt / 1000)   end   obj.dpt = dpt   obj.len = dtlens[ dpt ]   obj.address = dbobj.address   if not obj.len then     alert('invalid data type ' .. obj.address .. ' ' .. tostring(dpt))     return   end   return obj end local function initobjects(objects)   if type(objects) ~= 'table' then     return   end   for addr, obj in pairs(objects) do     if type(obj) == 'string' then       obj = { address = obj }     end     local dbobj = grp.find(obj.address)     if dbobj then       obj = initobject(obj, dbobj)     else       alert('missing object ' .. obj.address)       obj = nil     end     objects[ addr ] = obj   end end _M.setmapping = function(map)   for _, smap in pairs(map) do     initobjects(smap.registers)     initobjects(smap.inputregisters)   end   mapping = map end return _M

Thanks in advance

Peppe

[admin]

For testing purposes you can connect both LM RS485 ports together. Then use Read test in Modbus tab. Make sure that port settings match.

[gdimaria]

so, you are saying to connect both LM RS485 each other and then use the read test.... on which of 3 rtu? is that correct?

by the way, in mbrtu:open('/dev/RS485-1', 9600, 'E', 8, 1, 'H') what means 'H' ?

Thanks

Peppe

[admin]

Use RS485-1 in the script. Configure RTU1 to use RS485-2.
'E', 8, 1, 'H' means Even parity, 8 data bits, 1 stop bit and Half duplex mode

[gdimaria]

ok....

just to be sure

I have to connect 

RS485-1                        RS485-2

A                        to               B

B                        to               A


That's correct?

[Daniel]

No A-A, B-B

[gdimaria]

No A-A, B-B

ok thanks

---

Can I do the same with spaceLynk? how to connect and configure?

[Daniel]

No as it has only one RS485 port but if you have more than one you can connect two.

[gdimaria]

Last question:

I have some knx address as commands and others as states... how I have to set them? Both coil and registers as in my script ? or a different way?

Code:

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mb.setmapping({   [1] = {       coils = {       [1] = '2/1/11', -- state on/off       [4] = '2/1/14', -- state set %     },     registers = {       [0] = '2/1/10', -- command on/off      -- [1] = '2/1/11', -- stato on/off       [3] = '2/1/13', -- command set %      -- [4] = '2/1/14', -- stato set %     }   } })

[Daniel]

Coils are bits only, registers are numeric.
Coil and registers have its own ranges.