25.02.2021, 15:25
The illegal data error seems to come from the device sending some extra byte when it should not. Unfortunately it's hard to tell why the connection stops working. Try this test script which discards any stale data before reading.
Code:
if not mb then
require('luamodbus')
mb = luamodbus.tcp()
mb:setresponsetimeout(5)
mb:open('10.36.0.25', 502)
res, err = mb:connect()
if res then
buffer = {}
mb:setdebug(function(msg)
buffer[ #buffer + 1 ] = msg
end)
else
log('modbus connect failed ' .. tostring(err))
mb:close()
mb = nil
end
end
if mb then
mb:flush()
reg10240, reg10241, reg10242, reg10243, reg10244, reg10245, reg10246, reg10247 = mb:readregisters(10240, 8)
if reg10240 then
mains_l1_voltage = reg10240 / 10
mains_l2_voltage = reg10242 / 10
mains_l3_voltage = reg10244 / 10
genset_l1_voltage = reg10246 / 10
log('voltage values', mains_l1_voltage, mains_l2_voltage, mains_l3_voltage, genset_l1_voltage)
else
log('modbus read failed ' .. tostring(reg10241))
mb:close()
mb = nil
end
log(table.concat(buffer))
buffer = {}
end