Пример протокола ModBus ASCII
Материал из WebHMI Wiki
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:
-- MODBUS ASCII Demo Driver
function parseAddress ()
-- do something here
end
function createDevices ()
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, 16}});
addDevice({name = "IR", shift = 0, base = 10, xtraFields = {4, 0}});
end
local errorCount = 0;
function intToPair(val, count)
local str = string.upper(string.format("%0" .. count .. "x", val));
local res = {};
for i = 1, count do
res[i] = string.byte(string.sub(str, i, i));
end
return res;
end
function pairToInt(a, b)
local str = string.char(a) .. string.char(b);
local n = tonumber(str, 16);
return n;
end
function LRC(table, start, count)
local lrc = 0;
local i = start;
while (i < (start+count)) do
local str = string.char(table[i]) .. string.char(table[i + 1]);
local n = tonumber(str, 16);
lrc = lrc + n;
i = i + 2;
end
lrc = bit.band(lrc, 255);
return 256 - lrc;
end
function readRegister (reg, device, unitId)
local request = {};
-- ASCII header
request[1] = 58;
-- slave address
local addr = intToPair(unitId, 2);
request[2] = addr[1];
request[3] = addr[2];
-- function code
local fnCode = intToPair(device.xtraFields[1], 2);
request[4] = fnCode[1];
request[5] = fnCode[2];
-- address of register
local intAddr = intToPair(reg.internalAddr, 4);
request[6] = intAddr[1];
request[7] = intAddr[2];
request[8] = intAddr[3];
request[9] = intAddr[4];
-- count of registers
local count = 1;
if (reg.dataType == 3) then -- double word
count = 2;
end
count = intToPair(count, 4);
request[10] = count[1];
request[11] = count[2];
request[12] = count[3];
request[13] = count[4];
-- LRC
local lrc = LRC(request, 2, 12);
lrc = intToPair(lrc, 2);
request[14] = lrc[1];
request[15] = lrc[2];
-- CR LF
request[16] = 13;
request[17] = 10;
local res = sendBytes(request);
if (res == false) then
DEBUG("Can't send bytes");
return false;
end
local response = {};
-- read Header
response = readBytes(7);
if (response == false) then
DEBUG("Can't read response");
return false;
end
res = #response;
if (res ~= 7) then
errorCount = errorCount + 1;
if (errorCount > 3) then
closeConnection();
errorCount = 0;
end
DEBUG("Can't read header");
return false;
end
if (response[1] ~= request[1]) then
ERROR("Wrong protocol");
return false;
end
if (response[2] ~= request[2] or response[3] ~= request[3]) then
ERROR("Wrong UnitID in response");
return false;
end
if (response[4] ~= request[4] or response[5] ~= request[5]) then
ERROR("Wrong function code in response");
return false;
end
local length = pairToInt(response[6], response[7]);
if (length < 1) then
ERROR("Wrong length in response");
return false;
end
local response2 = {};
response2 = readBytes(length * 2 + 4);
if (response2 == false) then
DEBUG("Can't read response2");
return false;
end
res = #response2;
local result = {};
local resp = {};
for i=1,#response do
resp[i] = response[i];
end
local c = #response;
for i=1,#response2 do
resp[c+i] = response2[i];
end
local lrc_resp = LRC(resp, 2, 6 + length * 2);
local lrc_actual = pairToInt(response2[length*2 + 1], response2[length*2 + 2]);
if (lrc_resp ~= lrc_actual) then
ERROR("Wrong LRC in response");
return false;
end
if (length >= 1) then
for i = 1, length do
result[i] = pairToInt(response2[i*2 - 1], response2[i*2]);
end
end
return result;
end
function writeRegister (reg, device, unitId, newValue)
local request = {};
-- ASCII header
request[1] = 58;
-- slave address
local addr = intToPair(unitId, 2);
request[2] = addr[1];
request[3] = addr[2];
if (reg.dataType == 3) then -- double word should be handled in a special way
if (device.xtraFields[3] == 0) then
ERROR("Can't write these type of registers (" .. device.name .. ")");
return false;
end
-- function code
local fnCode = intToPair(device.xtraFields[3], 2);
request[4] = fnCode[1];
request[5] = fnCode[2];
-- address of register
local intAddr = intToPair(reg.internalAddr, 4);
request[6] = intAddr[1];
request[7] = intAddr[2];
request[8] = intAddr[3];
request[9] = intAddr[4];
local count = intToPair(2, 4);
request[10] = count[1];
request[11] = count[2];
request[12] = count[3];
request[13] = count[4];
-- message length
local dataLen = intToPair(4, 2);
request[14] = dataLen[1];
request[15] = dataLen[2];
local valpairs = intToPair(newValue, 8);
for i=1,8 do
request[15+i] = valpairs[i];
end
-- LRC
local lrc = LRC(request, 2, 22);
lrc = intToPair(lrc, 2);
request[24] = lrc[1];
request[25] = lrc[2];
-- CR LF
request[26] = 13;
request[27] = 10;
local res = sendBytes(request);
if (res == false) then
DEBUG("Can't send request");
return false;
end
local response = {};
response = readBytes(17);
if (response == false) then
DEBUG("Can't read response");
return false;
end
res = #response;
if (res ~= 17) then
DEBUG("Wrong response length");
return false;
end
if (response[1] ~= request[1]) then
ERROR("Wrong protocol");
return false;
end
local lrc_resp = LRC(response, 2, 12);
local lrc_actual = pairToInt(response[14], response[15]);
if (lrc_resp ~= lrc_actual) then
ERROR("Wrong LRC in response");
return false;
end
if (response[2] ~= request[2] or response[3] ~= request[3]) then
ERROR("Wrong UnitID in response");
return false;
end
if (response[4] ~= request[4] or response[5] ~= request[5]) then
ERROR("Wrong function in response");
return false;
end
if (response[6] ~= request[6] or response[7] ~= request[7] or response[8] ~= request[8] or response[9] ~= request[9]) then
ERROR("Wrong register address in response");
return false;
end
if (response[10] ~= request[10] or response[11] ~= request[11] or response[12] ~= request[12] or response[13] ~= request[13]) then
ERROR("Wrong register count");
return false;
end
if (response[16] ~= request[16] or response[17] ~= request[17]) then
ERROR("Wrong footer in response");
return false;
end
else
if (device.xtraFields[2] == 0) then
ERROR("Can't write these type of registers (" .. device.name .. ")");
return false;
end
-- function code
local fnCode = intToPair(device.xtraFields[2], 2);
request[4] = fnCode[1];
request[5] = fnCode[2];
-- address of register
local intAddr = intToPair(reg.internalAddr, 4);
request[6] = intAddr[1];
request[7] = intAddr[2];
request[8] = intAddr[3];
request[9] = intAddr[4];
-- data
local val = newValue;
if (reg.dataType == 0) then
if (val > 0) then
val = 255*256;
else
val = 0;
end
end
local valpairs = intToPair(val, 4);
request[10] = valpairs[1];
request[11] = valpairs[2];
request[12] = valpairs[3];
request[13] = valpairs[4];
-- LRC
local lrc = LRC(request, 2, 12);
lrc = intToPair(lrc, 2);
request[14] = lrc[1];
request[15] = lrc[2];
-- CR LF
request[16] = 13;
request[17] = 10;
local res = sendBytes(request);
if (res == false) then
DEBUG("Can't send bytes");
return false;
end
local response = {};
local requestLen = #request;
response = readBytes(requestLen);
if (response == false) then
DEBUG("Can't read response");
return false;
end
res = #response;
if (res ~= requestLen) then
DEBUG("Wrong response length");
return false;
end
for i = 1,res do
if (response[i] ~= request[i]) then
DEBUG("Wrong response");
return false;
end
end
end
return true;
end