Measurement Computing USB-1208HS-4AO - Manual (Page 15)

USB-1208HS-4AO User's Guide Functional Details
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Both the period and time delay ranges are 50 ns to 107.4 seconds.
Figure 11. USB-1208HS-4AO PWM timer channel
Trigger input
The TRIG connection is an external digital trigger input. The trigger mode is software selectable for:
 Level-sensitive or edge-sensitive
 Rising or falling edge
 High or low level
The default setting at power up is edge sensitive, rising edge.
Retrigger
The acquisition uses the trigger settings for positive edge/negative edge and level-sensitive/edge-sensitive, but
automatically re-arms the trigger after it is activated
Power output
You can use the two +5V connections to supply power to external devices or circuitry. These terminals can
output up to 285 mA. Refer to Figure 4 and Figure 3 on page 10 for the location of this pin.
Caution! The
+5V terminals are outputs. Do not connect to an external power supply or you may damage
the USB-1208HS-4AO and possibly the computer.
Ground
The analog ground ( AGND ) connections provide a common ground for all analog I/O channels. The ground
( GND ) connections provide a common ground for the digital I/O, timer/counter I/O, timer, clock I/O, and the
+5 V terminals.