Measurement Computing USB-2020 - Manual (Page 16)

USB-2020 User's Guide Functional Details
Pull-up default configuration (factory default)
Pull-down configuration
Figure 6. Pull-up and pull-down jumper configurations (J10)
An external pull-up resistor can be used to pull the DIO bit up to a voltage that exceeds the internal 5 V pull-up
voltage (15 V maximum). Be aware that this would place the 47k internal pull up resistor in a parallel
resistance configuration that could offset the logic high voltage level.
Figure 7. Digital I/O external resistor configuration
Trigger input
Both the
TRIG IN
BNC connector and the
TRIG IN
IDC pin are external digital trigger/gate inputs that you can
configure through software.
An analog scan can have a trigger or a gate, but not both. For example, you cannot use an analog trigger and use
the
TRIG IN
BNC connector to gate at the same time.
A trigger or gate can be digital or analog.

Digital triggers can be configured for rising or falling edge, or for high or low level.
 Analog triggers can be configured for software-selectable high or low level, or for rising or falling edge
with software-selectable hysteresis.
 Digital gates can be configured for high or low level.
 Analog gates can be configured for software-selectable high or low level, or for in or out of software-
selectable window.
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