This might be a bit off topic, but here goes:

My client would like to use a "control gear" type of switch to control this new device. The heart of the machine is T89C51 micro, with its portpins protected by 74hc243 buffers. On the buffer output there is a series resistor and after that a pull up resistor.

The switch is a Legrand "Signis" type, rated at 690 volts and 16A! They dont publish any low level data, and it shurely isn't the most obvius choice for the aplication in hand, but as you know the client is always right.

I gues that it will work okay for the first six to twelve months; by then the contacts are so dirty that my 5V and a few mA's can't get through.

I thought about increasing both voltage and current
by simply adding a (schottky)diode in series with the input, and a new pull-up resistor, connected to +24 V.

Is this a kosher way to do it, or..........

Any comments aprecheated

Ha' en god weekend

Per Guldmann