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1wire [2019/01/09 14:32] (current)
emozolyak created
Line 1: Line 1:
 +====== 1-Wire ======
 +
 +Since WebHMI version 1.11.0.3453 1-Wire protocol support were added.
 +
 +At the current moment, it is possible to poll the DS18x20 family of sensors. To work with the 1-Wire bus you need a special USB adapter. E.g. like this one:
 +
 +{{::​usb-1-wire.jpg?​direct&​200|}}
 +
 +When creating a connection, you must select:
 +  *PLC model: 1-Wire
 +  *Protocol: DS18x20 or DS2480 depending on the adapter you use
 +
 +{{::​1wire_select_adapter.png?​direct&​500|}}
 +
 +Device: corresponding USB UART adapter.
 +
 +{{::​1wire_select_bus.png?​direct&​800|}}
 +
 +When creating a register for thermometers,​ it is necessary to specify such register address format: "​T"​ + thermometer address in hexadecimal. For example, **T28FFC85115150131**.
 +
 +For more convenient use of the system, under the address line of the register address, a link appears //Select 1-Wire device...//:​
 +{{::​one_wire_search.png?​direct&​600|}}
 +
 +If you click on it, the system will search for all devices on the 1-Wire bus and a new window will pop up where all these devices will be listed. For thermometers DS18x20 in the corresponding line will be a link with the correct register address for this thermometer. If you click on this address, the window will automatically close and the selected address will be inserted in the address field of the register: ​
 +{{::​select_1w_sensor.png?​direct&​600|}}
 +
 +  P.S. The speed of reading 1-wire values ​​depends strongly on the selected UART-converter. So, the adapters on the 
 +  FTDI chip will make big delays due to LatencyTimer'​s timeout. Reading one temperature reading on this adapter ​
 +  takes about 100ms.
  

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