mirror of
https://github.com/MikaylaFischler/cc-mek-scada.git
synced 2024-08-30 18:22:34 +00:00
339 lines
12 KiB
Lua
339 lines
12 KiB
Lua
-- #REQUIRES comms.lua
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-- modbus function codes
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local MODBUS_FCODE = {
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READ_COILS = 0x01,
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READ_DISCRETE_INPUTS = 0x02,
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READ_MUL_HOLD_REGS = 0x03,
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READ_INPUT_REGS = 0x04,
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WRITE_SINGLE_COIL = 0x05,
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WRITE_SINGLE_HOLD_REG = 0x06,
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WRITE_MUL_COILS = 0x0F,
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WRITE_MUL_HOLD_REGS = 0x10,
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ERROR_FLAG = 0x80
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}
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-- modbus exception codes
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local MODBUS_EXCODE = {
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ILLEGAL_FUNCTION = 0x01,
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ILLEGAL_DATA_ADDR = 0x02,
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ILLEGAL_DATA_VALUE = 0x03,
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SERVER_DEVICE_FAIL = 0x04,
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ACKNOWLEDGE = 0x05,
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SERVER_DEVICE_BUSY = 0x06,
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NEG_ACKNOWLEDGE = 0x07,
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MEMORY_PARITY_ERROR = 0x08,
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GATEWAY_PATH_UNAVAILABLE = 0x0A,
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GATEWAY_TARGET_TIMEOUT = 0x0B
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}
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-- new modbus comms handler object
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function new(rtu_dev)
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local self = {
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rtu = rtu_dev
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}
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local _1_read_coils = function (c_addr_start, count)
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local readings = {}
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local access_fault = false
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local _, coils, _, _ = self.rtu.io_count()
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local return_ok = (c_addr_start + count) <= coils
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if return_ok then
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for i = 0, (count - 1) do
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readings[i], access_fault = self.rtu.read_coil(c_addr_start + i)
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if access_fault then
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return_ok = false
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readings = MODBUS_EXCODE.SERVER_DEVICE_FAIL
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break
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end
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end
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else
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readings = MODBUS_EXCODE.ILLEGAL_DATA_ADDR
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end
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return return_ok, readings
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end
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local _2_read_discrete_inputs = function (di_addr_start, count)
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local readings = {}
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local access_fault = false
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local discrete_inputs, _, _, _ = self.rtu.io_count()
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local return_ok = (di_addr_start + count) <= discrete_inputs
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if return_ok then
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for i = 0, (count - 1) do
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readings[i], access_fault = self.rtu.read_di(di_addr_start + i)
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if access_fault then
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return_ok = false
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readings = MODBUS_EXCODE.SERVER_DEVICE_FAIL
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break
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end
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end
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else
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readings = MODBUS_EXCODE.ILLEGAL_DATA_ADDR
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end
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return return_ok, readings
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end
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local _3_read_multiple_holding_registers = function (hr_addr_start, count)
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local readings = {}
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local access_fault = false
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local _, _, _, hold_regs = self.rtu.io_count()
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local return_ok = (hr_addr_start + count) <= hold_regs
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if return_ok then
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for i = 0, (count - 1) do
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readings[i], access_fault = self.rtu.read_holding_reg(hr_addr_start + i)
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if access_fault then
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return_ok = false
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readings = MODBUS_EXCODE.SERVER_DEVICE_FAIL
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break
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end
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end
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else
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readings = MODBUS_EXCODE.ILLEGAL_DATA_ADDR
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end
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return return_ok, readings
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end
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local _4_read_input_registers = function (ir_addr_start, count)
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local readings = {}
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local access_fault = false
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local _, _, input_regs, _ = self.rtu.io_count()
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local return_ok = (ir_addr_start + count) <= input_regs
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if return_ok then
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for i = 0, (count - 1) do
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readings[i], access_fault = self.rtu.read_input_reg(ir_addr_start + i)
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if access_fault then
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return_ok = false
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readings = MODBUS_EXCODE.SERVER_DEVICE_FAIL
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break
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end
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end
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else
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readings = MODBUS_EXCODE.ILLEGAL_DATA_ADDR
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end
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return return_ok, readings
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end
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local _5_write_single_coil = function (c_addr, value)
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local response = nil
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local _, coils, _, _ = self.rtu.io_count()
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local return_ok = c_addr <= coils
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if return_ok then
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local access_fault = self.rtu.write_coil(c_addr, value)
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if access_fault then
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return_ok = false
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readings = MODBUS_EXCODE.SERVER_DEVICE_FAIL
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end
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else
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response = MODBUS_EXCODE.ILLEGAL_DATA_ADDR
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end
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return return_ok, response
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end
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local _6_write_single_holding_register = function (hr_addr, value)
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local response = nil
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local _, _, _, hold_regs = self.rtu.io_count()
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local return_ok = hr_addr <= hold_regs
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if return_ok then
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local access_fault = self.rtu.write_holding_reg(hr_addr, value)
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if access_fault then
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return_ok = false
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readings = MODBUS_EXCODE.SERVER_DEVICE_FAIL
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end
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end
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return return_ok
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end
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local _15_write_multiple_coils = function (c_addr_start, values)
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local response = nil
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local _, coils, _, _ = self.rtu.io_count()
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local count = #values
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local return_ok = (c_addr_start + count) <= coils
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if return_ok then
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for i = 0, (count - 1) do
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local access_fault = self.rtu.write_coil(c_addr_start + i, values[i + 1])
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if access_fault then
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return_ok = false
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readings = MODBUS_EXCODE.SERVER_DEVICE_FAIL
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break
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end
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end
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end
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return return_ok, response
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end
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local _16_write_multiple_holding_registers = function (hr_addr_start, values)
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local response = nil
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local _, _, _, hold_regs = self.rtu.io_count()
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local count = #values
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local return_ok = (hr_addr_start + count) <= hold_regs
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if return_ok then
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for i = 0, (count - 1) do
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local access_fault = self.rtu.write_coil(hr_addr_start + i, values[i + 1])
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if access_fault then
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return_ok = false
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readings = MODBUS_EXCODE.SERVER_DEVICE_FAIL
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break
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end
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end
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end
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return return_ok, response
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end
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-- validate a request without actually executing it
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local check_request = function (packet)
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local return_code = true
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local response = { MODBUS_EXCODE.ACKNOWLEDGE }
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if #packet.data == 2 then
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-- handle by function code
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if packet.func_code == MODBUS_FCODE.READ_COILS then
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elseif packet.func_code == MODBUS_FCODE.READ_DISCRETE_INPUTS then
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elseif packet.func_code == MODBUS_FCODE.READ_MUL_HOLD_REGS then
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elseif packet.func_code == MODBUS_FCODE.READ_INPUT_REGISTERS then
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elseif packet.func_code == MODBUS_FCODE.WRITE_SINGLE_COIL then
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elseif packet.func_code == MODBUS_FCODE.WRITE_SINGLE_HOLD_REG then
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elseif packet.func_code == MODBUS_FCODE.WRITE_MUL_COILS then
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elseif packet.func_code == MODBUS_FCODE.WRITE_MUL_HOLD_REGS then
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else
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-- unknown function
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return_code = false
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response = { MODBUS_EXCODE.ILLEGAL_FUNCTION }
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end
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else
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-- invalid length
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return_code = false
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response = { MODBUS_EXCODE.NEG_ACKNOWLEDGE }
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end
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-- default is to echo back
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local func_code = packet.func_code
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if not return_code then
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-- echo back with error flag
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func_code = bit.bor(packet.func_code, MODBUS_FCODE.ERROR_FLAG)
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end
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-- create reply
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local reply = comms.modbus_packet()
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reply.make(packet.txn_id, packet.unit_id, func_code, response)
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return return_code, reply
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end
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-- handle a MODBUS TCP packet and generate a reply
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local handle_packet = function (packet)
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local return_code = true
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local response = nil
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if #packet.data == 2 then
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-- handle by function code
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if packet.func_code == MODBUS_FCODE.READ_COILS then
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return_code, response = _1_read_coils(packet.data[1], packet.data[2])
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elseif packet.func_code == MODBUS_FCODE.READ_DISCRETE_INPUTS then
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return_code, response = _2_read_discrete_inputs(packet.data[1], packet.data[2])
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elseif packet.func_code == MODBUS_FCODE.READ_MUL_HOLD_REGS then
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return_code, response = _3_read_multiple_holding_registers(packet.data[1], packet.data[2])
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elseif packet.func_code == MODBUS_FCODE.READ_INPUT_REGISTERS then
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return_code, response = _4_read_input_registers(packet.data[1], packet.data[2])
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elseif packet.func_code == MODBUS_FCODE.WRITE_SINGLE_COIL then
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return_code, response = _5_write_single_coil(packet.data[1], packet.data[2])
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elseif packet.func_code == MODBUS_FCODE.WRITE_SINGLE_HOLD_REG then
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return_code, response = _6_write_single_holding_register(packet.data[1], packet.data[2])
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elseif packet.func_code == MODBUS_FCODE.WRITE_MUL_COILS then
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return_code, response = _15_write_multiple_coils(packet.data[1], packet.data[2])
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elseif packet.func_code == MODBUS_FCODE.WRITE_MUL_HOLD_REGS then
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return_code, response = _16_write_multiple_holding_registers(packet.data[1], packet.data[2])
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else
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-- unknown function
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return_code = false
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response = MODBUS_EXCODE.ILLEGAL_FUNCTION
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end
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else
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-- invalid length
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return_code = false
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end
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-- default is to echo back
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local func_code = packet.func_code
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if not return_code then
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-- echo back with error flag
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func_code = bit.bor(packet.func_code, MODBUS_FCODE.ERROR_FLAG)
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if type(response) == "nil" then
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response = { }
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elseif type(response) == "number" then
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response = { response }
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elseif type(response) == "table" then
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response = response
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end
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end
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-- create reply
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local reply = comms.modbus_packet()
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reply.make(packet.txn_id, packet.unit_id, func_code, response)
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return return_code, reply
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end
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-- return a SERVER_DEVICE_BUSY error reply
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local reply__srv_device_busy = function (packet)
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-- reply back with error flag and exception code
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local reply = comms.modbus_packet()
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local fcode = bit.bor(packet.func_code, MODBUS_FCODE.ERROR_FLAG)
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local data = { MODBUS_EXCODE.SERVER_DEVICE_BUSY }
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reply.make(packet.txn_id, packet.unit_id, fcode, data)
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return reply
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end
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-- return a NEG_ACKNOWLEDGE error reply
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local reply__neg_ack = function (packet)
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-- reply back with error flag and exception code
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local reply = comms.modbus_packet()
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local fcode = bit.bor(packet.func_code, MODBUS_FCODE.ERROR_FLAG)
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local data = { MODBUS_EXCODE.NEG_ACKNOWLEDGE }
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reply.make(packet.txn_id, packet.unit_id, fcode, data)
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return reply
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end
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-- return a GATEWAY_PATH_UNAVAILABLE error reply
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local reply__gw_unavailable = function (packet)
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-- reply back with error flag and exception code
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local reply = comms.modbus_packet()
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local fcode = bit.bor(packet.func_code, MODBUS_FCODE.ERROR_FLAG)
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local data = { MODBUS_EXCODE.GATEWAY_PATH_UNAVAILABLE }
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reply.make(packet.txn_id, packet.unit_id, fcode, data)
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return reply
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end
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return {
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check_request = check_request,
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handle_packet = handle_packet,
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reply__srv_device_busy = reply__srv_device_busy,
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reply__neg_ack = reply__neg_ack,
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reply__gw_unavailable = reply__gw_unavailable
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}
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end
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