Is home flag input configurable for either sinking or sourcing for PCI-7344?

[william J]

Please advise if the home flag input can be configured for either sinking or sourcing?  The circuit diagram on page 33 of 67 in the National Instruments 7340 User Manual shows a sourcing type input.  Please if this can be reconfigured to a sinking input?

Thank you.

Bill Rabe

Automation & Process Controls

bill@apc-inc.com

PHONE 952-898-1430

FAX       952-898-3696 

[Buechsenschuetz]

I have never heard or read anything about possibilities to change the hardware configuration of this input.

But what is your problem with this input? The pull-up resistor to +5V is 3.3kOhms so any circuit able to sink 1.5mA will be able to drive this input.

[s_a_s]

Hello Bill,

It is not possible to change the configuration of the home flag input directly.  As a sourcing signal, it will require a sinking connection for it to work properly.  You could however use external circuitry to change either the logic of the home flag, or the logic for your input.

Best Regards,

Arves

[Buechsenschuetz]

There is just one application which comes to my mind where such a feature might be needed: some opto switches come with a pnp transistor output which is not able to sink any current. With one more transistor added, such an output could be converted into a npn transistor output which will sink current and thus be able to drive the home switch input.