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--- custom_protocols [2019/01/09 12:15] – [readRegister] emozolyak
+++ custom_protocols [2019/01/09 12:19] – [Modbus RTU in custom protocol version] emozolyak
@@ Line 446: / Line 446: @@
   *ModBus TCP
   *ModBus ASCII
-  *Modbus RTU.
+  *[[http://docs.webhmi.com.ua/modbus_rtu_custom|Modbus RTU]].
-===== Modbus RTU in custom protocol version =====
-An example of custom protocol for Modbus RTU.
-  *Type: Serial Port
-  *Address validation: ^(C[0-9]+)$|^(DI[0-9]+)$|^(HR[0-9]+)$|^(IR[0-9]+)$
-  *Validation error message: Invalid register address. Valid ModBus addresses are Cxxx, DIxxx, IRxxx, HRxxx.
-Code:
-<code lua>
--- MODBUS RTU Demo Driver
-function createDevices ()
-                                                     -- read FC write FC
-  addDevice({name = "C",  shift = 0, base = 10, xtraFields = {1, 5}})
-  addDevice({name = "DI", shift = 0, base = 10, xtraFields = {2, 0}})
-  addDevice({name = "HR", shift = 0, base = 10, xtraFields = {3, 6}})
-  addDevice({name = "IR", shift = 0, base = 10, xtraFields = {4, 0}})
-end
-local errorCount = 0
--- template
-local request = {1, 2,      -- slaveId FC
-,  4,  -- addr high lo
-,  6, -- count hi lo
-,  0      -- crc high lo
-                }
-EXCEPTIONS = {"Illegal Function",     "Illegal Data Address",
-               "Illegal Data Value",  "Slave Device Failure",
-               "Acknowledge",         "Slave Device Busy",
-               "Negative Acknowledge", "Memory Parity Error",
-               "Gateway Path Unavailable", "Gateway Target Device Failed to Respond"
-              }
-function readRegister (reg, device, unitId)
-                             --- FORMING REQUEST -----------
-      -- slave address
-  request[1] = unitId;
-  -- function code
-  request[2] = device.xtraFields[1]
-  -- address of register
-  request[3] = GetHiByte(reg.internalAddr)
-  request[4] = GetLoByte(reg.internalAddr)
-  -- count of registers
-  local count = 1
-      if (reg.dataType == 3) then -- double word
-        count = 2
-      end
-  request[5] = GetHiByte(count)
-  request[6] = GetLoByte(count)
-   -- CRC
-  local crc = GetCRC(request, 2)
-  local crcLo,crcHi = 0,0 -- will be used below too
-  crcLo = GetLoByte(crc) ; request[7] = crcLo
-  crcHi = GetHiByte(crc) ; request[8] = crcHi
-                           -- SENDING REQUEST
-  if not (sendBytes(request)) then
-      DEBUG("Can't send bytes")
-      return false
-  end
-                           -- RECEIVING REPLY ---
-  local respHead, respData, respCRC = {}, {}, {}
-    -- read Header with length
-  respHead = readBytes(3)
-  if (respHead == false) then
-      DEBUG("Can't read response")
-      return false
-  end
-  if (respHead[1] ~= request[1]) then
-      ERROR("Wrong slaveID in response!")
-      return false
-  end
-  if (respHead[2] ~= request[2]) then
-      if (respHead[2] >= 0x81) then
-          ERROR("EXCEPTION: "..EXCEPTIONS[bit.band(respHead[2], 0x0F)])
-          readBytes(2) -- read till the end
-      else
-          ERROR("Wrong Func Code in response")
-      end
-   return false;
-  end
-  local resp_Lentgh = respHead[3];
-        respData = readBytes(resp_Lentgh)
-  if (respData == false) then
-      DEBUG("Can't read response");
-      return false;
-  end
-  -- check CRC in reply
-  local tmpResponseTab = {}
-    for i,v in ipairs(respHead) do
-        table.insert(tmpResponseTab, v)
-    end
-    for i,v in ipairs(respData) do
-        table.insert(tmpResponseTab, v)
-    end
-  crc = GetCRC(tmpResponseTab, 0)
-  crcLo = GetLoByte(crc)
-  crcHi = GetHiByte(crc)
-  respCRC = readBytes(2)
-  if (respCRC == false) then
-      DEBUG("Can't read response");
-      return false;
-  end
-  if (respCRC[1] ~= crcLo) or (respCRC[2] ~= crcHi) then
-      DEBUG("Wrong CRC in reply! "..string.format("%X", crcLo).." "..string.format("%X", crcHi));
-      return false;
-  end
-  if (device.name == "DI") or (device.name == "C")  then
-      if (resp_Lentgh ~= count) then
-          ERROR("Wrong length in response");
-          return false;
-      end
-  else
-      if (resp_Lentgh ~= count*2) then
-          ERROR("Wrong length in response");
-          return false;
-      end
-  end
-                                  -- RETURN DATA --
-    return GetHexFromTable(respData)
-end -- readRegister
-function writeRegister (reg, device, unitId, newValue)
-    -- for read-only don't write
-                                    DEBUG("Going to write this value "..newValue)
-    if device.name == "IR" or device.name == "DI" then
-         ERROR("Can't write these type of registers (" .. device.name .. ")")
-        return true
-    end
-    local wrRequest = {};
-    -- slave address
-    wrRequest[1] = unitId;
-    -- function code
-    wrRequest[2] = device.xtraFields[2]
-    -- address of register
-    wrRequest[3] = GetHiByte(reg.internalAddr)
-    wrRequest[4] = GetLoByte(reg.internalAddr)
-    local dataTable = GetDataAsTable(newValue, device.dataType)
-        local coilsTmp = 0
-        if (device.name == "C") then
-            coilsTmp = dataTable[2] * 0xFF
-            dataTable[2] = dataTable[1]
-            dataTable[1] = coilsTmp
-        end
-    DEBUG("#dataTable now "..#dataTable)
-    wrRequest[5] = dataTable[1]
-    wrRequest[6] = dataTable[2]
-    -- CRC
-    local crc, crcLo, crcHi = 0,0,0
-    crc = GetCRC(wrRequest, 0)
-    crcLo = GetLoByte(crc)
-    crcHi = GetHiByte(crc)
-    wrRequest[7] = crcLo
-    wrRequest[8] = crcHi
-    DEBUG("Going to send this packet "..table.concat(wrRequest))
-    local res = sendBytes(wrRequest);
-    if (res == false) then
-        DEBUG("Can't send request");
-        return false;
-    end
-    -- читаем ответ
-    res = readBytes(8)
-    if (res == false) then
-        DEBUG("Can't receive reply")
-        return false
-    end
-    if (table.concat(res) ~= table.concat(wrRequest)) then
-        DEBUG("Response does not match!")
-        return false
-    end
-    if (#dataTable == 4) then
-        -- DWORD
-        -- repeat steps for 2nd Word
-        wrRequest[3] = GetHiByte(reg.internalAddr + 1)
-        wrRequest[4] = GetLoByte(reg.internalAddr + 1)
-        wrRequest[5] = dataTable[3]
-        wrRequest[6] = dataTable[4]
-        crc, crcLo, crcHi = GetCRC(wrRequest, 0), GetLoByte(crc) , GetHiByte(crc)
-        wrRequest[7] = crcLo
-        wrRequest[8] = crcHi
-        res = sendBytes(wrRequest);
-        if (res == false) then
-            DEBUG("Can't send request");
-            return false;
-        end
-    end
-    return true
-end
--- Calculating CRC for RTU
-function GetCRC(req, offset)
-  local crc = 0xffff
-  local mask = 0
-  -- iterate bytes
-for i=1,#req-offset do
-      crc = bit.bxor(crc,req[i])
-      -- iterate bits in byte
-      for j=1,8 do
-          mask = bit.band(crc,0x0001)
-          if mask == 0x0001 then
-              crc = bit.rshift(crc,1)
-              crc = bit.bxor(crc,0xA001)
-          else
-              crc = bit.rshift(crc,1)
-          end
-      end
-end
-     return crc
-end
-function GetHiByte(c)
-                                   DEBUG("Going to get high byte from "..c)
-   return bit.rshift(c,8)
-end
-function GetLoByte(input_val)
-                                    DEBUG("Going to get low byte from "..input_val)
-    return bit.band(input_val,0xFF)
-end
-function GetHexFromTable(inputTab)
-    -- get hex and concat it to number via string operatoin
-                                    DEBUG("entered GetHexFromTable with table - "..table.concat(inputTab))
-    local numberAs_String = ""
-    local tmpStr = ""
-        for i,v in pairs(inputTab) do
-            tmpStr = string.format("%X",v)
-            if (#tmpStr == 1) then
-                tmpStr = "0"..tmpStr
-            end
-            numberAs_String = numberAs_String..tmpStr
-        end
-                                DEBUG("number is "..numberAs_String.." decimal = "..numberAs_String)
-    return tonumber(numberAs_String, 16)
-end
-function GetDataAsTable(value, datatype)
-    local highWord, lowWord, tmpTable = 0, 0, {}
-    if (datatype ~= 3) then
-        DEBUG("getdataastable - going to process value  "..value)
-        tmpTable[1] = GetHiByte(value) ; DEBUG(tmpTable[1])
-        tmpTable[2] = GetLoByte(value) ; DEBUG(tmpTable[2])
-    else
-        highWord = bit.rshift(value,16)
-        lowWord = bit.band(c,0xFFFF)
-        tmpTable[1] = GetHiByte(highWord)
-        tmpTable[2] = GetLoByte(highWord)
-        tmpTable[3] = GetHiByte(lowWord)
-        tmpTable[4] = GetLoByte(lowWord)
-    end
-    return tmpTable
-end
-</code>