08.01.2016, 08:46
️ This script is outdated use this script instead: https://forum.logicmachine.net/showthread.php?tid=4288
Simple example of how to implement Modbus TCP slave via a resident script (sleep time = 0). It only supports binary objects as coils and 1-byte / 2-byte integer objects as registers. Number of coils and registers is not limited, object mapping can be set by filling coils, registers and regdt tables.
Simple example of how to implement Modbus TCP slave via a resident script (sleep time = 0). It only supports binary objects as coils and 1-byte / 2-byte integer objects as registers. Number of coils and registers is not limited, object mapping can be set by filling coils, registers and regdt tables.
Code:
if not mb then
require('genohm-scada.eibdgm')
require('luamodbus')
-- list of coil mapping, starting from 0
coils = { '1/1/1', '1/1/2' }
-- list of register mapping, starting from 0
registers = { '2/2/2', '3/3/3' }
-- list of register data types, element count must match registers table
regdt = { dt.int8, dt.uint16 }
-- knx group write callback
function knxgroupwrite(event)
local value
-- try to find matching coil
for id, addr in ipairs(coils) do
if event.dst == addr then
value = knxdatatype.decode(event.datahex, dt.bool)
mb:setcoils(id - 1, value)
end
end
-- try to find matching register
for id, addr in ipairs(registers) do
if event.dst == addr then
value = knxdatatype.decode(event.datahex, regdt[ id ])
mb:setregisters(id - 1, value)
end
end
end
-- coil write callback
function mbwritecoils(coil, value)
local addr = coils[ coil + 1 ]
if addr then
grp.write(addr, value, dt.bool)
end
end
-- register write callback
function mbwriteregisters(register, value)
local addr = registers[ register + 1 ]
if addr then
grp.write(addr, value, regdt[ register + 1])
end
end
-- knx group monitor, handles group writes
knxclient = eibdgm:new({ timeout = 0.1 })
knxclient:sethandler('groupwrite', knxgroupwrite)
-- modbus slave, listen on all interfaces and default port 502
mb = luamodbus.tcp()
mb:open('0.0.0.0', 502)
-- setting slave id is optional
-- mb:setslave(1)
mb:setreceivetimeout(0.1)
mb:setmapping(#coils, 0, #registers, 0)
-- init coils
for id, addr in ipairs(coils) do
value = grp.getvalue(addr)
mb:setcoils(id - 1, value)
end
-- init registers
for id, addr in ipairs(registers) do
value = grp.getvalue(addr)
mb:setregisters(id - 1, value)
end
-- set callbacks for coil and register write
mb:setwritecoilcb(mbwritecoils)
mb:setwriteregistercb(mbwriteregisters)
end
-- handle modbus and knx
mb:handleslave()
knxclient:loop(0.1)