LXM32M | 3 Basics |
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3.4.6Examples
3.4.6.1 Example of "Function Code" 3
Reading an error memory entry. Since the Modbus addresses of the parameters of an error memory entry are contiguous (ascending order), a single Modbus request is sufficient.
Parameters _ERR_number (15362), _ERR_class (15364), _ERR_time (15366) and _ERR_qual (15368).
Modbus request Structure of the Modbus request:
Field | Bytes | Value | Meaning |
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Function Code | 1 | 3 | Read Multiple Registers |
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Starting Address | 2 | 15362 (3C02h) | Address of the first parameter to be read |
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Quantity Of Regis- | 2 | 8 | Number of the 16 bit values to be read = 8 |
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Modbus response Structure of the positive Modbus response:
Field | Bytes | Value | Meaning |
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Function Code | 1 | 3 | Read Multiple Registers | |
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Byte Count | 1 | 16 | Number of bytes: 8 bytes of data | |
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Registers Value | 16 | 32 bit value | _ERR_number, 15362 (error number) | |
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| 32 bit value | _ERR_class, 15364 (error class) | |
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| 32 bit value | _ERR_time, 15366 | (error time) |
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| 32 bit value | _ERR_qual, 15368 | (error qualifier) |
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3.4.6.2 Example of "Function Code" 16
Writing of the software limit switches. Since these parameters also have consecutive addresses, a single Modbus request is sufficient:
Parameters MON_swLimP (1544) and MON_swLimN (1546).
Modbus request Structure of the Modbus request:
Field | Bytes | Value | Meaning |
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Function Code | 1 | 16 | Write Multiple Registers |
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Starting Address | 2 | 1544 (608h) | Address of the first parameter to be written |
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Quantity Of Regis- | 2 | 4 | Number of parameters = 4 (8 bytes of data) |
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Byte Count | 1 | 8 | Number of bytes: 8 bytes of data |
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Registers Value | 8 | 32 bit value | MON_swLimP, 1544 |
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| 32 bit value | MON_swLimN, 1546 |
Modbus response Structure of the positive Modbus response:
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Field | Bytes | Value | Meaning | ||
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V1.01, | Function Code | 1 | 16 | Write Multiple Registers | |
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Starting Address | 2 | 1544 (608h) | Address of the parameter | ||
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0198441113843, | Quantity Of Regis- | 2 | 4 | Number of parameters = 4 (8 bytes of data) | |
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