Crystal Instruments Spider - Page 78

Spider DSA User’s Manual
78
Pin name
Pin number
Pin Description
OUT1 - OUT8
1, 2, 3, 4, 5, 6, 7, 8
8 output signal pins. Connect these pins
to the input signal pins of the external
device.
IN1 - IN8
9, 14, 15, 16, 17, 18, 19, 20
8 input signal pins. Connect output
signals from the external device to these
pins.
+3.3V
13, 25
+3.3V power supply (for internal use
only)
+12V
10
+12V power supply
GND
11, 23
Digital ground
EX_GND
12, 24
External ground for isolated external
devices
EX_PWR
21, 22
External power, usually +12 V,
reference ground is EX_GND.
Table 1: Spider-81 DIO Port Pin Description
The digital inputs are opto-isolated and take a 12 V signal. The output device must
supply the voltage. The circuit is shown in the figure below.
VCC
EX_GND
EX_PWR
Input pin
Spider81
Switch
Switch
External power
supply 12VDC
Input pin
External device
Optocoupler
Optocoupler
Logic input
Logic input
VCC
Figure 29. Input Circuit
The figure below shows an example of connecting a push-button switch to an
input. When the switch is ON, the corresponding input bit is 0, and when the
switch is OFF, the input bit is 1. Momentarily depressing the switch will trigger an
input event in the channel. RL should not be greater than 6 kΩ.