Behavior of RevPi DIO input nodes at turn on in a Node-Red setting

[Daniele.tampieri]

The title says all: I'd like to know if a message is generated at turn on to make a Node-Red system aware of the status of DIO inputs. I see that when an input changes, the associated payload property assumes a string value "1": however the other properties have an integer 0 or 1 value, thus I'd like to know if a message is generated even there's no input variation.

[crismancich]

Hi Daniele,

use a start-up-trigger node with a RevPi get pin. Make sure you add some delay so that the pi is already botted up completely.
https://flows.nodered.org/node/node-red ... up-trigger

[Daniele.tampieri]

HI crismancich,
Thank you for the flow you suggested: do this implies that it is not possible to "take a picture" of all inputs jointly, for example by using some initial state of the node revpi-multiple-input? I mean, if I need to know the state of all inputs at a given time, possibly in the form of a JSON object

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{ "I_1" :  x1, ... "I_14" : x14 }

, should I acquire it by doing some kind of (triggered) ladder flow by using the

Code: Select all

revpi-getpin

node as you did?

Hi Daniele,

use a start-up-trigger node with a RevPi get pin. Make sure you add some delay so that the pi is already botted up completely.
https://flows.nodered.org/node/node-red ... up-trigger

[Daniele.tampieri]

Hi crismancich,
I solved the problem by using your suggestion in a ladder structure, precisely the one shown in the picture below:

Schermata 2021-12-18 alle 18.25.57.png (498.37 KiB) Viewed 4403 times

The input of this submodule is activated at start-up: the shown subflow then takes a screenshot of the input status and send it as a payload object wit the same structure as the `revpi-multiple-input` node payload, so I can use the same processing node downstream.