User Manual

USB-204 User's Guide Functional Details
11
Figure 6 shows the jumper configured for pull-down.
Figure 6. Pull-down jumper
Configure the jumper for pull-up to pull the digital inputs high (+5V).
Proper LED alignment
When placing the circuit board within the housing, align the board LEDs with the top of the housing before
attaching the housing bottom.
Trigger input
The TRIG terminal is an external digital trigger input. The trigger mode is software-selectable for edge- or
level-sensitive. The trigger is automatically re-armed after it is activated.
Counter input
The CTR terminal is a 32-bit event counter that can accept frequency inputs up to 1 MHz. The internal counter
increments when the TTL levels transition from low to high.
Voltage output
The user voltage output (+VO) terminal can output up to 100 mA maximum at approximately +5V. You can use
this terminal to supply power to external devices or circuitry.
Caution! The +VO terminal is an output. Do not connect to an external power supply or you may damage
the device and possibly the computer.
Ground
The analog ground (AGND) terminals provide a common ground for all analog channels. The digital ground
(GND) terminals provide a common ground for the digital, counter, pacer I/O, and power terminal.
For more information about signal connections
For more information about analog and digital signal connections, refer to the Guide to DAQ Signal
Connections at www.mccdaq.com/pdfs/DAQ-Signal-Connections.pdf.