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- In the function determineNextEvent () the last target time will be the Period length added to calculate the next execution time. If the connection was interrupted for a long time, however, they accumulate many versions of the then with a shorter period length (tv_earliest_next_trigger_time) are processed. If the cycle times anyway are already tightly laid out, this can lead to an overload. Must be changed. The next execution time must be the current time plus Be cycle time.
| Modbus_Master_Status | ||
|---|---|---|
| 16 | 0x10 | Initialization is failed |
| 17 | 0x11 | This device is not readable(false IP, Cabel?) |
| Modbus_Action_Status | ||
|---|---|---|
| 1 | ILLEGAL FUNCTION | The applied function code is not allowed. Check whether the right function code is used. |
| 2 | ILLEGAL DATA ADDRESS | The applied address is not valid. The register is either read-only or not existed. Please check the address. |
| 3 | ILLEGAL DATA VALUE | At least one part of the applied data is invalid. It is possible that the count of register is exceed. Please check the value. |
| 13 | INVALID DATA | The Slave answered with an unknown package to me. This can occur, for example, after the connection has been interrupted. Please check your wiring. |
| 104 | CONNECTION RESET BY PEER |
This is a TCP problem. It can occur if the addressed host has no instance of the modbus slave running. |
| 110 | CONNECTION TIMED OUT | The slave didn't respond in time or not at all. Please check your configuration and cabling. |
| Modbus_Master_Status | ||
|---|---|---|
| 16 | 0x10 | Initialization is failed |
| 17 | 0x11 | Serial connection can't be opened (wrong device name, invalid configuration) |
| Modbus_Action_Status | ||
|---|---|---|
| 1 | ILLEGAL FUNCTION | The applied function code is not allowed. Check whether the right function code is used. |
| 2 | ILLEGAL DATA ADDRESS | The applied address is not valid. The register is either read-only or not existed. Please check the address. |
| 3 | ILLEGAL DATA VALUE | At least one part of the applied data is invalid. It is possible that the count of register is exceed. Please check the value. |
| 11 | FAILED TO RESPOND | Resource temporarily unavailable. Usually means that the device is not present on the network. |
| 12 | INVALID CRC | A disturbed packet was received from the slave. This can occur, for example, after the connection has been interrupted. Please check your wiring. |
| 13 | INVALID DATA | An incomplete packet was received from the slave. This can occur, for example, after the connection has been interrupted. Please check your wiring. |
| 110 | CONNECTION TIMED OUT | The slave didn't respond in time or not at all. Please check your configuration and cabling. |
| ID | |
|---|---|
| 1 | Illegal function |
| 2 | Illegal data address |
| 3 | Illegal data value |
| 4 | Slave device or server failure |
| 5 | Acknowledge |
| 6 | Slave device or server is busy |
| 7 | Negative acknowledge |
| 8 | Memory parity error |
| 10 | Gateway path unavailable |
| 11 | Target device failed to respond |
| 12 | Invalid CRC |
| 13 | Invalid data |
| 14 | Invalid exception code |
| 15 | Too many data |
Further information in document about configuration and I/O
{
"config": {
"modbusActions": [
{
"SlaveAddress" : 1,
# Address of the Modbus slave which is addressed by the
# command
"FunctionCode" : 2,
# Modbus function code see below
"RegisterAddress" : 1,
# Modbus register address (start address) of the slave
"QuantityOfRegisters" : 8,
# Number of Modbus registers that are written / read
"ActionInterval" : 100000,
# Time interval in which the command is sent from the
# master in µsec. For the user, information in 1 ms
# steps is sufficient
"ProcessImageStartByte" : 2,
# The offset in the Pi process image for the Modbus data
"Action ID" : 1
# Ascending ID for the command for information in the
# event of an error
},
{
"SlaveAddress" : 1,
"FunctionCode" : 3,
"RegisterAddress" : 1200,
"QuantityOfRegisters" : 8,
"ActionInterval" : 200000,
"ProcessImageStartByte" : 18,
"Action ID" : 2
},
{
"SlaveAddress" : 2,
"FunctionCode" : 16,
"RegisterAddress" : 1024,
"QuantityOfRegisters" : 8,
"ActionInterval" : 500000,
"ProcessImageStartByte" : 2,
"Action ID" : 3
}
]
}
}Important function codes are marked with '*'.The other function codes may not need to be supported.
| Code | ID | |
|---|---|---|
| * | eREAD_COILS | 0x01 |
| * | eREAD_DISCRETE_INPUTS | 0x02 |
| * | eREAD_HOLDING_REGISTERS | 0x03 |
| * | eREAD_INPUT_REGISTERS | 0x04 |
| * | eWRITE_SINGLE_COIL | 0x05 |
| * | eWRITE_SINGLE_REGISTER | 0x06 |
| eREAD_EXCEPTION_STATUS | 0x07 | |
| * | eWRITE_MULTIPLE_COILS | 0x0F |
| * | eWRITE_MULTIPLE_REGISTERS | 0x10 |
| eREPORT_SLAVE_ID | 0x11 | |
| eWRITE_MASK_REGISTER | 0x16 | |
| eWRITE_AND_READ_REGISTERS | 0x17 |
Coils and Discrete Inputs are one bit in size. In the process image, however, one byte should be reserved for each bit.Holding registers and input registers have a size of 2 bytes.
For each Modbus command, an additional byte must be reserved in the Pi process image for error messages.
For the virtual device, a byte must also be reserved in the Pi process image for error messages.
For each Modbus command and the virtual device, a bit must be reserved to reset the error byte in the Pi process image