MODBUS RTU Quad2000 communication protocol
Supported device types and versions
Communication line configuration
Communication station configuration
I/O tag configuration
Literature
Changes and modifications
Document revisions
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- Communication line category: Serial, SerialOverUDP Device Redundant.
- Transmission parameters according to Quad 2000 (baud rate 300 up to 19200 Baud, 8 data bits, no parity, 1 stop bit).
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- Communication protocol: MODBUS RTU Quad2000.
- Address is MODBUS address that is set in Quad 2000.
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Configuration dialog box - tab "Protocol parameters".
They influence some optional parameters of protocol. You can define the following parameters:
Table 1
| Key word | Full name | Description | Unit | Default value | ||||||
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| Retry Count | Number of retry calls when an error in communication occurs. | - | 2 | ||||||
| Retry Timeout | Delay between retry calls if an error in communication occurs. | ms | 100 millisec. | ||||||
| Wait First Timeout | First waiting on the response after sending a call. | ms | 100 millisec. | ||||||
| Wait Timeout | Delay between the readings of a response until it is completed. | ms | 100 millisec. | ||||||
| Max Wait Retry | Number of retry response reading until it is completed. | - | 20 |
String with protocol parameters is written according to this rule:
Key_word=value;Key_word=value; ...Example:
WT=100;MWR=20;
If a key word with valid value has not been found in the initial string, default value is used according to Table 1.
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I/O tags: Ai, Ao, Ci, Co, Di, Do
For relation between D2000 Value Type and Modbus Data Type Pre is applied this table:
| Modbus Data Type | D2000 Value Type |
|---|---|
| Coil Status - 0x references | Do |
| Input Status - 1x references | Di |
| Input Registers - 3x references | Ai, Ci |
| Holding Registers - 4x references | Ao, Co |
The address is Modbus register number in the range of 0 to 65535.
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