Measurement Computing USB-2408 Series - Manual (Page 10)

10
Chapter 3
Functional Details
External components
USB-2408 Series devices have the following external components:
 USB connector
 LEDs
 Screw terminals
Figure 2 shows the location of each component.
1 Screw terminal pins 23 to 44 4 USB Connector
2 Status LED 5 Screw terminal pins 1 to 22
3 Activity LED
Figure 2. USB-2408 Series components
USB connector
The USB connector provides 5 V power and communication. No external power supply is required.
LEDs
USB-2408 Series devices have two LEDs – STATUS and ACTIVITY .
 The
Status LED is lit when the device is detected and installed on the computer.
 The
Activity LED indicates the communication status of a device. This LED blinks when data is
transferred, and is off when the device is not communicating.
Screw terminals
USB-2408 Series devices have two banks of screw terminals. Screw terminal functions for DIFF and SE modes
are identified in Figure 4 and Figure 3.
The USB-2408 Series device screw terminals provide the following connections:
 16 SE (
CH0 to CH15 – see Figure 3) or eight DIFF ( CH0H/CH0L to CH7H/CH7L ) analog input connections
 Eight digital I/O connections (
DI00 to DI07 )
 Two analog output connections (
AOUT0 , AOUT1 ) – USB-2408-2AO only
 Two counter inputs (
CTR0 , CTR1 )
 One power output (
+5V )
 10 analog grounds (
AGND ), four digital grounds (D GND ), and one chassis ground ( CHAS )