Modbus Protocol Specification
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- Điều hướng trang này:
- 2.2.6 06 Preset Single Register
| 2.2.5 05 Force Single Coil
Forces a single coil (0x reference) to either ON or OFF. When broadcast, the function forces the same coil reference in all attached slaves. The maximum parameters supported by various controller models are listed on page . Note: The function will override the controller's memory protect state and the coil's disable state. The forced state will remain valid until the controller's logic next solves the coil. The coil will remain forced if it is not programmed in the controller's logic. Query The query message specifies the coil reference to be forced. Coils are addressed starting at zero-coil 1 is addressed as 0. The reguested ON / OFF state is specified by a constant in the query data field. A value of FF 00 hex requests the coil to be ON. A value of 00 00 requests it to be OFF. All other values are illegal and will not affect the coil. Here is an example of a request to force coil 173 ON in slave device 17: http://www.modicon.com/techpubs/dcon7.html (10 of 36) [1/11/2000 10:41:04 PM] Response The normal response is an echo of the query, returned after the coil state has been forced. Here is an example of a response to the query: 2.2.6 06 Preset Single Register Presets a value into a single holding register (4x reference). When broadcast, the function presets the same register reference in all attached slaves. The maximum parameters supported by various controller models are listed on page . Note: The function will override the controller's memory protect state. The preset value will remain valid in the register until the controller's logic next solves the register contents. The register's value will remain if it is not programmed in the controller's logic. Query The query message specifies the register reference to be preset. Registers are addressed starting at zero-register 1 is addressed as 0. The reguested preset value is specified in the query data field. M84 and 484 controllers use a 10-bit binary value, with the six high order bits set to zeros. All other controllers use 16-bit values. Here is an example of a request to preset register 40002 to 00 03 hex in slave device 17: http://www.modicon.com/techpubs/dcon7.html (11 of 36) [1/11/2000 10:41:04 PM] Response The normal response is an echo of the query, returned after the register contents have been preset. Here is an example of a response to the query: tải về 0.61 Mb. Chia sẻ với bạn bè của bạn:
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