Added Example ModbusRTUTemperatureSensor #4
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Added ModbusRTUTemperatureSensor example to the library ArduinoModbus
| - Z \/\/ Y set to OFF | ||
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| created 16 July 2018 | ||
| by Sandeep Mistry |
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I don't think I made this sketch :)
Please update the date and name accordingly.
| /* | ||
| Modbus RTU Temeperature Sensor | ||
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| This sketch show how to use the modbus library, in in order to sent a request to a slave RTU sensor |
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Suggestion: This sketch shows you how to interact with a Modbus RTU temperature and humidity sensor. It reads the temperature and humidity values every 5 seconds and outputs them to the serial monitor.
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| Circuit: | ||
| - MKR board | ||
| - TModbus RS485 Temperature |
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There is extra "T" at the start, we should add the product URL to I think
| - Z connected to B/Z of the Modbus RTU sensor | ||
| - Jumper positions | ||
| - FULL set to OFF | ||
| - Z \/\/ Y set to OFF |
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I think the termination should be set to ON
| - Jumper positions | ||
| - FULL set to OFF | ||
| - Z \/\/ Y set to OFF | ||
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You didn't mention the VCC connection for the sensor.
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| #include <ArduinoModbus.h> | ||
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| float temperature, humidity; |
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let's put the variables on one line each please.
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| void loop() { | ||
| //send a reading request to the RTU slave with id=1, type=HOLDING_REGISTERS address=0, number of values to read, nb=2 |
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change to:
// send a Holding registers read request to (slave) id 1, for 2 registers
also make sure if a comment is too long to split it to multiple lines.
| Serial.println(ModbusRTUClient.lastError()); | ||
| } else { | ||
| //if the request goes fine read the value with the read() function | ||
| short rawtemperature = ModbusRTUClient.read(); |
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we need an explanation of what the sensor returns and why we need to divide by 10.0.
added some comments to the ModbusRTUTemperatureSensor example
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Added a comment on the example ModbusRTUTemperatureSensor.ino
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| Serial.println(ModbusRTUClient.lastError()); | ||
| } else { | ||
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| // If the request goes fine, the sensor sent the readings as bytes packet, |
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holding registers are actually 16-bits in size.
| } else { | ||
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| // If the request goes fine, the sensor sent the readings as bytes packet, | ||
| // through the read() function is possible read the measurments. |
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| // If the request goes fine, the sensor sent the readings as bytes packet, | ||
| // through the read() function is possible read the measurments. | ||
| // the readings is parsed as a short integer from the packets |
| short rawtemperature = ModbusRTUClient.read(); | ||
| short rawhumidity = ModbusRTUClient.read(); | ||
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| // Is required divide by 10.0 the value readed, because the sensor sent the |
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readed -> read, sent -> sends
| short rawhumidity = ModbusRTUClient.read(); | ||
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| // Is required divide by 10.0 the value readed, because the sensor sent the | ||
| // readings as an integer obtained multipling the float value readed by 10 |
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it's a divide not multiply :)
the raw values need to be divided by 10 to get the temperature in Celsius and the humidity reading as a percentage.
Changed comment in ModbusRTUTemperatureSensor example.
| - MKR board | ||
| - Winners® Modbus RS485 Temperature and Humidity: | ||
| https://www.banggood.com/Modbus-RS485-Temperature-and-Humidity-Transmitter-Sensor-High-Precision-Monitoring-p-1159961.html?cur_warehouse=CN | ||
| - External power Supply |
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What voltage and current is needed?
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@Rocketct from the product page "Working voltage: 9-36V"
| Serial.println(ModbusRTUClient.lastError()); | ||
| } else { | ||
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| // If the request goes fine, the sensor sends the readings, this are |
| } else { | ||
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| // If the request goes fine, the sensor sends the readings, this are | ||
| // stored in the holding register and through the read() function is |
| short rawtemperature = ModbusRTUClient.read(); | ||
| short rawhumidity = ModbusRTUClient.read(); | ||
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| // Is required divide by 10.0 the raw value to get the temperature in Celsius |
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Let's change the order here:
To get the temperature in Celsius and the humidity reading as a percentage, divide the raw value by 10.0.
Changed comments in the example ModbusRTUTemperatureSensor.ino
Added a comment on the example ModbusRTUTemperatureSensor.ino
| - Power supply V+ connected to V+ sensor | ||
| - The Working voltage range of the sensor, from product page, is 9-36 V | ||
| - Set the Power supply's voltage to a value between 9 - 36 V | ||
| - Set the Power supply's current limit to 1 A |
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why doesn't the current need to be limited? Could someone use a fixed 9v 5A supply?
Added ModbusRTUTemperatureSensor example to the library ArduinoModbus