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kikesala May 30, 2019 04:24 AM

Good Morning. I am working with an SDM-IO16 to which I am going to connect sensors all / nothing that I configure with the following function:
SDMIO16 (ENTRY (), IO16_STAT1,1,90,2222,2222,2222,2222,1.0,0).
My problem comes when once all the inputs are set they are automatically set high and to cause change in the input I have to apply 0v. I do not have anything connected to the inputs.

I only configure and make the following voltage measurements:
between mass and input: 5v
between mass and mass: 0v
between input and 5v: 0v.

Are the entries in this module negative logic?
How can I reverse the logic?
Thanks greetings.

kikesala Jun 4, 2019 01:07 AM


aps Jun 5, 2019 05:57 AM

The inputs are not negative logic, but to allow easy use with volt-free contacts, the input is biased to 5V via a 100K resistor.  Please see figure 2 in the manual which shows you the input circuit.

The 5V bias should not affect most active logic level systems.

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