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ISO1212: ISO1212

Part Number: ISO1212

We are using ISO1212 component for 24V digital output to 5V digital output level translation.

For this application we would be using EJ2889 module. EJ2889 is a 16-channel digital output (24 V DC, 0.5 A output) module from Beckhoff and it is a ground switching module, which means when the Digital Output channel (DO_x) is "ON" it sinks the FGND. So the Channel state would be "LOW".

when the Digital Output channel (DO_x) is "OFF", the corresponding channel would be connected with +24V supply. So the Channel state would be "HIGH".

For your reference, I have attached the Schematics.

We have a technical Query on ISO1212:

  • When the Digital output is "HIGH" (Connected with +24V pull up resistor), will there be any impact on the Output side (OUT_1 & OUT_2) due to the leakage current from the Digital output module.

Note: EJ2889 module has an Internal pull up resistor connected with +24V supply in all the output channels.

  • Hi Nafisa,

    Hi Lakshmi,

    Thanks for reaching out.

    From the explanation you have provided, I understand that DO_x will be either connected to GND or left floating (but internal pull-up will make it go +24V). When DO_x is connected to GND, the corresponding output of ISO1212 will go HIGH. When DO_x is left floating then the corresponding output in ISO1212 will go LOW. I assuming this is how you wanted the output of ISO1212 to be.

    When the Digital output is "HIGH" (Connected with +24V pull up resistor), will there be any impact on the Output side (OUT_1 & OUT_2) due to the leakage current from the Digital output module.

    This internal pull-up will make the effective voltage across ISO1212 inputs to be close to 0V. Thus, there shouldn't be any leakage current going through the device and even if there is a leakage current, it doesn't affect the logic state outputs of ISO1212. Additionally, ISO1212 inputs have an internal reverse protection diode and hence, the leakage current will be negligible.

    I hope that answers your question, thanks.


    Regards,
    Koteshwar Rao