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ICOM-manual
Opto inputs
The ICOM-241 has eight optocoupler inputs suited for an input voltage range
of 5...12 VDC. To use higher input voltages, as 24V for example, an additional
serial resistor in the input line is used. The resistor value is selected in
accordance to 4...50mA input current needed for the logical “1” level.
The internal resistance is 680 Ohm / 0,25 W. If now another input voltage is
needed, the totally required resistance can be calculated with the following
formula:
3
R
ges
= (U
E
-1,3V)/I
D
U
E
= Input voltage
I
D
= Current into the optocoupler
R
ges
= Total resistance
Example:
Is e.g. an input voltage of 24 V with a current of 10 mA wanted, you get from
the above formula Rges = 2270 Ohm. This means either the internal 680 Ohm
resistor has be replaced with a 2200 Ohm resistor (rounded to norm value), or
a resistor of 1590 Ohm has to be connected in series.
Attention:
When calculating the protective resistance the maximum dissipation of the
resistor has to be considered!
Tiny-Tiger
®
Port Optokoppler DB-25 socket
P80 Opto In0 1
P81 Opto In1 14
P82 Opto In2 2
P83 Opto In3 15
- Opto GND 3
The following program reads the status of the optocoupler inputs into a
variable and sends it out through serial port 0.
3-4
Wilke Technology GmbH • 0241 / 918 900 • http://www.wilke.de/ • support@wilke.de