PI-SPI-DIN-SDAFE not supported in Node Red

[PankGrundfos]

Hallo

I am hoping it is acceptable to post here for your Node Red package, as it is linked to this library

we have build a demo using your PI-SPI-DIN modules but we now realized that for the vpe-2701c overlay, the SDAFE AI reading is not available as an option in node red

I tried the longshot of using the SDAFE node from the vpe-3011b and vpe-2901a options, but these did not work which was not so surprising

is there anything we can do so we can read the value from the SDAFE board as we already have received everything and made the demo ?

The SDAFE carrier card is currently not supported by this library or the Node-RED library. It requires a slightly different command than the one used on the VPE-3011B and VPE-2901A.

One possible workaround is to use this code in a Python script and modify it so that it works with an exec node:

import spidev

from time import sleep

spi = spidev.SpiDev()
spi.open(0, 3)

i = 0
err = 0
while True:
    data = [0x00, i, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
    spi.xfer(data, 100000)
    i = (i + 1) % 4

    value = data[4] * 256 + data[5]
    print(value / 1000)

    if data[2] != 0x55 or data[11] != 0x55:
        err += 1
        print("Errors:", err)

    sleep(0.4)

i represents which SDAFE to read, starting from 0.

[PankGrundfos]

Would this workaround still work OK with the rests of the flows which are a combination of your Widgetlord 4AO nodes and Modbus RTU reader and writer

also my setup was the prototype so it uses a VPE-3011b, but the other demos are build using the SPI-DIN (vpe-2701c). Would I be able to test and modify the scrip on my VPE-3011b or does it have to be done on the vpe-2701c ?

Would this workaround still work OK with the rests of the flows which are a combination of your Widgetlord 4AO nodes and Modbus RTU reader and writer

It should work with that setup.

also my setup was the prototype so it uses a VPE-3011b, but the other demos are build using the SPI-DIN (vpe-2701c). Would I be able to test and modify the scrip on my VPE-3011b or does it have to be done on the vpe-2701c ?

The script will need to be modified to work with the VPE-3011B due to differences in the command that I mentioned previously. The main differences are that on the VPE-3011B each SDAFE has its own spidev device and the command string is two bytes shorter since the first two bytes are used for instructing the carrier module on which SDAFE to select.