Flexible
I/O
as digital input, digital
output, or analog input. In addition, up to 2 of these lines can be
configured as timers, and up to 2 of these lines can be configured as
counters. On the U3-HV, the first 4 flexible I/O are replaced with
dedicated high-voltage analog inputs.
The first 8 flexible I/O
lines (FIO0-FIO7) appear on built-in screw terminals. The other 8 flexible
I/O lines (EIO0-EIO7) are available on the DB15 connector.
Analog
Inputs
The LabJack U3 has up to
16 analog inputs available on the
flexible I/O lines. Single-ended measurements can be taken of any line
compared to ground, or differential measurements can be taken of any line
to any other line.
Analog input resolution is
12-bits. The range of single-ended low-voltage analog inputs on the U3-LV
is typically 0-2.4 volts or 0-3.6 volts, and the range of differential
analog inputs is typically ±2.4 volts (pseudobipolar only). For valid
measurements, the voltage on every analog input pin, with respect to
ground, must be within -0.3 to +3.6 volts.
On the U3-HV, the first 4
flexible I/O are replaced with dedicated high-voltage analog inputs. The
input range of these channels is ±10 volts or -10/+20 volts. The
remaining 12 flexible I/O are still available as described above, so the
U3-HV has 4 high-voltage analog inputs and up to 12 low-voltage analog
inputs.
Command/response (software
timed) analog input reads typically take 0.6-4.0 ms depending on number of
channels and communication configuration. Hardware timed input streaming
has a maximum rate that varies with resolution from 2.5 ksamples/s at
12-bits to 50 ksamples/s at about 10-bits.
Analog
Outputs
The LabJack U3 has 2 analog
outputs (DAC0 and DAC1) that are available on the screw terminals.
Each analog output can be set to a voltage between 0 and 5 volts with
10-bits of resolution.
The analog outputs are
updated in command/response mode, with a typical update time of 0.6-4.0 ms
depending on communication configuration. The analog outputs have filters
with a 3 dB cutoff around 16 Hz, limiting the frequency of output
waveforms to less than that.
Digital
I/O
The LabJack U3 has up to
20 digital I/O channels. 16 are
available from the flexible I/O lines, and 4 dedicated digital I/O
(CIO0-CIO3) are available on the DB15 connector. Each digital line can be
individually configured as input, output-high, or output-low. The digital
I/O use 3.3 volt logic and are 5 volt tolerant.
Command/response (software
timed) reads/writes typically take 0.6-4.0 ms depending on communication
configuration. The first 16 digital inputs can also be read in a hardware
timed input stream where all 16 inputs count as a single stream channel.
Timers
Up
to 2 flexible I/O lines can be configured as timers. The timers are very
flexible, providing options such as PWM output, pulse timing, pulse
counting, and quadrature input.
Counters
Up
to 2 flexible I/O lines can be configured as 32-bit counters.
I/O
Protection
All
I/O lines on the U3 are protected against minor overvoltages. The FIO
lines can withstand continuous voltages of up to +/- 10 volts, while the
EIO/CIO lines withstand continuous voltages of up to +/- 6 volts.
High
Channel Count Applications
By
using USB hubs, many LabJacks can be interfaced to a single PC, providing
an inexpensive solution for high channel count applications.
OEM
Version
The U3-LV-OEM or U3-HV-OEM
includes the board only without the enclosure and without most
through-hole components. See Section 2.12 of the U3 User's Guide for more
information and here are links to order the U3-LV-OEM or order the
U3-HV-OEM. Note that DAQFactory Express is not included with the OEM
versions.
Optional
Accessories
The
Labjack U3 has a number of optional accessories including terminal breakouts
isolation and signal conditioning modules.
|
