@redplc/node-red-rpi-ds18b20

2.0.4 • Public • Published

@redplc/node-red-rpi-ds18b20

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Node-RED node for ds18b20 temperature sensor using with redPlc nodes

ds18b20 digital temperature sensor

  • 9..12bit resolution.
  • Conversion time 93.75..750ms.
  • Measure range -55°C .. +125°C.
  • On range -10°C .. +85°C is accuracy ±0,5°C.
  • 1-Wire connection.
  • Power supply 3..5.5V external or over bus (parasite power).
  • Each sensor has a 64-Bit ID.

Usage

  • Install redPlc nodes.
  • Use redPlc s-inject node for trigger update.
  • Connect to first output on s-inject node.
  • For logical operations use redPlc nodes.
  • Data is exchanged with global context variable arrays.
  • Array index depends on the order of the sensors.
  • If you add/remove sensors, array index can be change.
  • This node works on Raspberry Pi with 32bit or 64bit OS.
  • The temperature values are in °C or °F.
  • To prevents locks only one node is allowed.
  • Enable 1-wire with raspi-config.
  • Default 1-wire pin on Raspberry pi is GPIO4.

Delay with reading multiple ds18b20 digital temperature sensor

The ds18b20 digital temperature sensor needs to read temperature:
9-bit resolution -> 93.75ms.
10-bit resolution -> 187.5ms.
11-bit resolution -> 375ms.
12-bit resolution -> 750ms. (default factory set)
Because the accuracy is ±0.5°C in the range from -10°C to +85°C,
I recommend operating the sensor with 9-bit resolution.
Please note that the times apply to one sensor.
This means 10x750ms (7.5s) for 10 sensors with 12bit resolution.
There is a way to read multiple sensors more quickly.
The 1-Wire drivers from RPi Linux are not used for this,
but the sensors are addressed with their 1-Wire protocol.
In the further version I will implement this 1-Wire protocol.

Set Sensor Resolution

You can change the sensor resolution with tool in subfolder setSensor.
File readme.txt describes how the tool is used.

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Install

npm i @redplc/node-red-rpi-ds18b20

Weekly Downloads

20

Version

2.0.4

License

Apache-2.0

Unpacked Size

226 kB

Total Files

16

Last publish

Collaborators

  • redplc