User Defined Protocol
User Defined Protocol
If the device does not support MODBUS standard, and the protocol is not list in PIStudio, then user can define the protocol by following instruction to realize simply communication functions like sending and receiving commands.
HMI Settings
| Items | Settings | Note |
| Protocol | User defined protocol | |
| Connection | RS485/RS232 | |
| Baud rate | 2400~187500 | |
| Stop bits | 1/ 2 | |
| Data bits | 7/ 8 | |
| Parity | None/ Even/ ODD |
Operating Procedures
Select [User defined protocol];
Click [User defined protocol] button to open setting window as below;
Configure user defined command;
| No | Item | Description |
| 1 | Instruction edit | The required command. |
| 2 | Mode | Write to address or read from the address. |
| 3 | Format | Encode format: HEX or ASCII. |
| 4 | Other | No receiving: HMI does not respond to the receiving command. Send after receiving: HMI responds to the receiving command. |
| 5 | Manually send | Respond once after trigger the address. Address: set the trigger address. |
| 6 | Add | Save this setting. |
| 7 | Cancel | Cancel current settings. |
| 8 | Add | Add a new command. |
| Edit | Edit the selected command. | |
| Delete | Delete the selected command. | |
| Clear | Clear all the commands. | |
| 9 | Instruction list | Display all current commands. |
| 10 | Address List | Display all the addresses added. |
| 11 | Import | Import the command files to the instruction list. |
| Export | Export current command settings to local storage. | |
| Browse | Browse local command files. | |
| Advanced | Combine two commands. | |
| Exit | Complete editing and exit setting. |
Operating Procedures
Click [Add] to create a new command, as below shows;
Select mode, [Read] or [Write], and then select Format, there are two options [Hex] and [ASCII]. As below shows;
Other settings: [No receiving] means HMI only sends command, and it would not process the reply command which from device. [Send after receiving] means HMI will be receiving the command which from device firstly, and then sending the command to device. From example, when HMI receiving [00 FF 00] firstly and then send command, as below shows
Check [Manually send], and then please set the address for trigging, the setting range is 1~10, and please put Bit switch in project screen for it, and [OneCtrlBit] register is for [Manually send].
Instruction edit, when the data format is HEX, please use two numbers to represent one 16-bit number. ASCII format using characters to input;
Check settings;
| No | Items | Description |
| 1 | Add checking | Add checking command when receiving the data. |
| 2 | Back checking | Add control character in ASCII format. |
| Differ with send check | Set return checking. | |
| 3 | Add control character | Start position: select the start position of the data which need to check. |
| Length: The data length need to be checked. |
Object settings;
| No | Items | Description |
| 1 | Object settings | Object type: bit or word address; |
| Address: the triggering address; | ||
| Note: description to object; | ||
| 2 | Byte order | The numerical display order; |
Data length settings;
| No | Item | Description |
| 1 | Return data | Position: the start position of the return data. |
| Length: the return data length. | ||
| 2 | Write data | Position: the start position of the write data. |
| Length: the write data length. |
Instruction length settings
| No | Item | Description |
| 1 | Send length | The instruction data will only send designated data length. |
| 2 | Return length | The responds data length. |
| 3 | End code | Instruction will not be terminated until receiving [End code]; |
Cable Wiring
- RS485
- RS232
Example
This example use 2 HMI to simulate the communication of HMI and MCU.Showing you the meesages and the configuration to give you a better understanding of the User Defined protocol.