PCI-6514 Digital I/O voltage levels

[ninevoltz]

Is there a way to modify the PCI-6514 board so that it can detect sourcing voltages below 6V? Like, 5V perhaps? I see we have a bank of FODM2705 bi-directional opto-isolators with a resistor network. I assume this is the input bank. Which resistors could I change on the board to achieve a 5V source detection threshold? In what way will that change affect the maximum input voltage range?

Thanks!

[ninevoltz]

Here are photos of the board.

[alcava.cr]

Hi there, I don't recommend to tamper with the board. It might get damage during or after the modifications. The information from the User Manual states that the device can sense DC signals of at least 11 V. Instead of modifying the card you can add external circuitry that sends valid high logic levels to the card every time receives 5 volts (ex. transistor, relay, etc), that way you can be sure that the integrity of the card won't be compromised.