node-red-contrib-ifm-vvb001

Node-RED nodes that handles data transfers from IFM VVB sensors.

It includes the following nodes to retrieve monitoring data and transfer a raw acceleration BLOB*:

• get data: Gets the monitoring data from a VVB sensorO (V rms, A rms, A peak, Temperature and Crest).
• stream blob: Start a BLOB generation, extract it and convert it to m/s^2 unit.
• blob status: Return the status of the BLOB (ex: transmission is in progress or idle)
• abort blob : Run the abort BLOB transfer command. If the data transfer must be stopped before the end of the transfer, the transfer must be aborted. If not, a new Start command for reading the BLOB can't be raised with success.

*A BLOB is a record of raw acceleration at a high frequency (4 seconds at a frequency of 25 KHz which represents a time serie of 100K values)

Installation

In Node-RED (preferred)

• Via Manage Palette -> Search for "node-red-contrib-ifm-vvb001"

In a shell

Basic installation:

• go to the Node-RED "userDir" folder, typically ~/.node-red
• run npm install node-red-contrib-ifm-vvb001

Usage

Usage of get data

The easiest usage of the node get data is the following:

This node will return a modified msg with the following payload:

{
  "data": {
    "v_Rms": 0.0001,
    "a_Peak": 0.2,
    "a_Rms": 0,
    "Temperature": 33,
    "Crest": 4.2,
    "status": "OK"
  },
  "ts": "2022-07-07T21:32:22.133Z"
}

where:

• v_Rms is the speed root mean square in m/s
• a_Peak is the acceleration peak in m/s^2
• a_Rms is the acceleration root mean square in m/s^2
• Temperature is the temperature is celsius degrees
• Crest
• Status is the device status
• ts is the timestamp of this event

Usage of stream blob

The easiest usage of the node stream blob is the following:

The blob status node check if there is an ongoing blob acquisition. If it is the case, you cannot run stream blob until the actual blob transfer is finished or aborted using abort blob.

The stream blob node will return a modified msg with the following payload:

{
  "ts": "2022-07-07T21:43:34.542Z",
  "length": 200000,
  "acceleration": [
    1.010053825378418,
    1.0848726272583007,
    1.1035773277282714,
    "..."
  ],
  "crc": "4076F8421C"
}

where:

• length is the BLOB length in bytes (200K)
• acceleration is the raw acceleration recorded on 4 seconds using 25 KHz acquisition (vector of 100K values)
• crc is the CRC signature of the BLOB
• ts is the start timestamp of this recording