Embedded Systems LogicMachine5 - Page 209

209
61. -- request ok
62. else
63. -- reply with an error
64. if res[ 1 ]==nil then
65. return nil, res[2]
66. -- normal reply
67. else
68. return unpack(res)
69. end
70. end
71. end
Handler (resident script with 0 delay) configuration
1. mb:open()
Open Modbus TCP connection
2. mb:setslave(10)
set slave device id
3. mb:setmapping(10, 10, 10, 10)
set number coils, discrete inputs, holding registers and input registers
4.mb:setwritecoilcb(function(coil, value)...
callback function which is executed for each coil write
5. mb:setwriteregistercb(function(coil, value)...
callback function which is executed for each register write
Handler script example
1. -- modbus init
2. if not mb then
3. require('luamodbus')
4. mb = luamodbus.tcp()
5. mb:open()
6.
7. -- init slave storage for coils, discrete inputs, holding registers and input registers
8. mb:setmapping(10, 10, 10, 10)
9.
10. -- coil write callback
11. mb:setwritecoilcb(function(coil, value)
12. if coil == 0 then
13. grp.write('1/1/1', value, dt.bool)
14. else
15. alert('coil: %d = %s', coil, tostring(value))