node-red-contrib-redplc-rpi-ads1x15 v1.0.11

node-red-contrib-redplc-rpi-ads1x15

Node-Red node for ads1015/ads1115 analog to digital converter

Node Features

• Supports ads1015/ads1115 analog to digital converter
• Each input can be selected Single-Ended, Differential or Disabled
• ads1015 12bit conversion time 1ms/channel
• ads1115 16bit conversion time 10ms/channel
• Four selectable I2C addresses
• Output value is in mV
• Input range +/- 6.144V, 4.096V, 2.048V, 1.024V, 0.512V or 0.256V
• Scaling with factor and offset

Install

For using with Ladder-Logic install redPlc nodes

For using with other nodes, install module nodes

Install with Node-Red Palette Manager or npm command:

cd ~/.node-red
npm install node-red-contrib-redplc-rpi-ads1x15

Usage

This node writes to Node-Red global variables Update is triggered by redPlc cpu node or module-update node This node works only on Raspberry Pi with Raspberry Pi OS Enable I2C with raspi-config Consult datasheet for absolute maximum ratings

Analog Input (Variable IA):

Single-Ended Mode: |Input|Array-Index |:----|:---:| |IA0-GND|0| |IA1-GND|1| |IA2-GND|2| |IA3-GND|3|

Two Differential Inputs Mode: |Input|Array-Index |:---|:---:| |AI0-AI1|0| |AI1-AI3|1| |AI2-AI3|2| |AI0-AI3|3|

Scaling with Factor and Offset:

Formula:

Factor = (OH - OL) / (IH - IL)
Offset = OL - (IL * Factor)

Output = Input * Factor + Offset

Where:

IL = Input Low (mV), IH = Input High (mV) 
OL = Output Low, OH = Output High

Example:

Input: 0mV .. 10000mV, IL = 0, IH = 10000 Output: -20°C .. 60°C, OL = -20, OH = 60 Factor = (60 - (-20)) / (10000 - 0) = 0.008 Offset = (-20) - (0 * 0.008) = -20

Input = 4000mV Output = 4000 * 0.008 + (-20) = 12°C

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