Digital I/O; Internal Pull-Up/Pull-Down Capability - Measurement Computing USB-2416 User Manual

USB-2416 User's Guide

Digital I/O

The USB-2416 provides up to eight digital I/O lines with read/write rates of 500 port reads or single bit reads
per second.
Digital input voltage ranges of 0 V to 15 V are permitted, with thresholds of 0.6 V (low) and 2.6 V (high). Each
DIO channel is an open-drain, which, when used as an output, is capable of sinking up to 150 mA for direct
drive applications. The maximum sink current is 150 mA per eight-channel bank, or if all eight channels are
used, 18 mA (maximum) per channel.
Figure 13 is an example of a typical DIO connection. The figure represents connections for one channel. The
other seven channels are connected in the same manner.

Internal pull-up/pull-down capability

Each of the eight DIO bits on the USB-2416 has a 47 kΩ pull-up/pull-down resistor. To configure these bits for
the 0 V pull-down option, you must open the USB-2416 case to access the three-pin jumper labeled JP1.
To open the case and set the JP1 jumper, do the following.
1. Turn over the USB-2416 and rest it on its top on a flat, stable surface.
2. Remove the five screws shown in Figure 14 from the bottom of the module.
3. Holding both the top and bottom sections of the module, turn it over, rest it on the surface, and carefully
remove the top portion of the case.
Figure 13. Digital output connection example
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Functional Details