LabJack UE9 User manual

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UE9 User's Guide
This is the complete user's guide for the UE9, including documentation for the LabJackUD driver.
Includes specifications in Appendix A.
To make a PDF of the whole manual, click "Export all" towards the upper-right of this page. Doing so
converts these pages to a PDF on-the-fly, using the latest content, and can take 20-30 seconds.
Make sure you have a current browser (we mostly test in Firefox and Chrome) and the current version
of Acrobat Reader. If it is not working for you, rather than a normal click of "Export all" do a right-click
and select "Save link as" or similar. Then wait 20-30 seconds and a dialog box will pop up asking
you where to save the PDF. Then you can open it in the real Acrobat Reader, not embedded in a
browser. If you still have problems, try the "Print all" option instead. In addition, an export is attached
below, but will not always be the latest version.
If you are looking at a PDF or hardcopy, realize that the original is an online document at http://labjack.com/support/ue9/users-
guide.
Rather than using a PDF, though, we encourage you to use this web-based documentation. Some advantages:
We can quickly change or update content.
The site search includes the user's guide, forum, and all other resources at labjack.com. When you are looking for
something try using the site search.
For support, try going to the applicable user's guide page and post a comment. When appropriate we can then immediately
add/change content on that page to address the question.
One other trick worth mentioning, is to browse the table of contents to the left. Rather than clicking on all the links to browse, you
can click on the small black triangles to expand without reloading the whole page.
User's Guide
File attachment:
UE9_UG_Export_04282011.pdf
Preface
For the latest version of this and other documents, go to www.labjack.com.
Copyright 2012, LabJack Corporation
Package Contents:
The normal retail packaged UE9 or UE9-Pro consists of:
UE9 (-Pro) unit itself in red enclosure
USB cable (6 ft / 1.8 m)
Ethernet cable (6 ft / 1.8 m)
Power supply
Screwdriver
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Warranty:
The LabJack UE9 is covered by a 1 year limited warranty from LabJack Corporation, covering this product and parts against
defects in material or workmanship. The LabJack can be damaged by misconnection (such as connecting 120 VAC to any of the
screw terminals), and this warranty does not cover damage obviously caused by the customer. If you have a problem, contact
[e-mail] for return authorization. In the case of warranty repairs, the customer is responsible for shipping to LabJack
Corporation, and LabJack Corporation will pay for the return shipping.
Limitation of Liability:
LabJack designs and manufactures measurement and automation peripherals that enable the connection of a PC to the real-
world. Although LabJacks have various redundant protection mechanisms, it is possible, in the case of improper and/or
unreasonable use, to damage the LabJack and even the PC to which it is connected. LabJack Corporation will not be liable for
any such damage.
Except as specified herein, LabJack Corporation makes no warranties, express or implied, including but not limited to any implied
warranty or merchantability or fitness for a particular purpose. LabJack Corporation shall not be liable for any special, indirect,
incidental or consequential damages or losses, including loss of data, arising from any cause or theory.
LabJacks and associated products are not designed to be a critical component in life support or systems where malfunction can
reasonably be expected to result in personal injury. Customers using these products in such applications do so at their own risk
and agree to fully indemnify LabJack Corporation for any damages resulting from such applications.
LabJack assumes no liability for applications assistance or customer product design. Customers are responsible for their
applications using LabJack products. To minimize the risks associated with customer applications, customers should provide
adequate design and operating safeguards.
Reproduction of products or written or electronic information from LabJack Corporation is prohibited without permission.
Reproduction of any of these with alteration is an unfair and deceptive business practice.
Conformity Information (FCC, CE, RoHS):
See the Conformity Page and the text below:
FCC PART 15 STATEMENTS:
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC
Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in
a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used
in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment
in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his
own expense. The end user of this product should be aware that any changes or modifications made to this equipment without the
approval of the manufacturer could result in the product not meeting the Class B limits, in which case the FCC could void the user's
authority to operate the equipment.
Declaration of Conformity:
Manufacturers Name: LabJack Corporation
Manufacturers Address: 3232 S Vance St STE 100, Lakewood, CO 80227, USA
Declares that the product
Product Name: LabJack UE9 (-Pro)
Model Number: LJUE9 (-Pro)
conforms to the following Product Specifications:
EN 55011 Class B
EN 61326-1: 2002 General Requirements
and is marked with CE
RoHS:
The UE9 (-Pro) is RoHS compliant per the requirements of Directive 2002/95/EC.
1 - Installation on Windows
The LJUD driver requires a PC running Windows. For other operating systems, go to labjack.com for available support. Software
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will be installed to the LabJack directory which defaults to c:\Program Files\LabJack\.
Install the software first: Go to labjack.com/support/ue9.
Connect the USB cable: (See Section 2.2 for Ethernet installation tips) The USB cable provides data and power. After the UD
software installation is complete, connect the hardware and Windows should prompt with “Found New Hardware” and shortly after
the Found New Hardware Wizard will open. When the Wizard appears allow Windows to install automatically by accepting all
defaults.
Run LJControlPanel: From the Windows Start Menu, go to the LabJack group and run LJControlPanel. Click the “Find Devices”
button, and an entry should appear for the connected UE9 showing the serial number. Click on the “USB – 1” entry below the serial
number to bring up the UE9 configuration panel. Click on “Test” in the configuration panel to bring up the test panel where you can
view and control the various I/O on the UE9.
If LJControlPanel does not find the UE9, check Windows Device Manager to see if the UE9 installed correctly. One way to get to
the Device Manager is:
Start => Control Panel => System => Hardware => Device Manager
The entry for the UE9 should appear as in the following figure. If it has a yellow caution symbol or exclamation point symbol, right-
click and select “Uninstall” or “Remove”. Then disconnect and reconnect the UE9 and repeat the Found New Hardware Wizard as
described above.
1.1 - Control Panel Application (LJControlPanel)
The LabJack Control Panel application (LJCP.exe) handles configuration and testing of the UE9. Click on the “Find LabJacks”
button to search for connected devices.
Figure 1-1. LJControlPanel Main Window
Figure 1-1 shows the results from a typical search. The application found one UE9 connected by USB and Ethernet. It also found a
second UE9 that is accessible only by Ethernet. The USB connection has been selected in Figure 1-1, bringing up the
configuration window on the right side.
Refresh: Reload the window using values read from the device.
Write to Device: Write the values from the window to the device. Depending on the values that have been changed, the
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application might prompt for a device reset.
Reset: Click to reset the selected device.
Test: Opens the window shown in Figure 1-2. This window continuously writes to and reads from the selected LabJack.
Figure 1-2. LJControlPanel Test Window
Selecting Options=>Settings from the main LJControlPanel menu brings up the window shown in Figure 1-3. This window allows
some features to of the LJControlPanel application to be customized.
Figure 1-3. LJControlPanel Settings Window
Search for USB devices: If selected, LJControlPanel will include USB when searching for devices.
Search for Ethernet devices using UDP broadcast packet: Normally, Ethernet connected devices are found using a
broadcast of the DiscoveryUDP command documented in Section 5.2.3. On some networks, however, it might not be
desirable to broadcast these UDP packets. There are also situations where a network might have proper TCP
communication between the PC and LabJack, but the broadcast UDP packet does not work.
Search for Ethernet devices using specified IP addresses. When this option is selected, LJControlPanel will specifically
search over TCP using each address in the list. On some networks this might be preferred over the UDP broadcast search.
1.2 - Self-Upgrade Application (LJSelfUpgrade)
Both processors in the UE9 have field upgradeable flash memory. The self-upgrade application shown in Figure 1-4 programs the
latest firmware onto either processor.
First, put valid values in the “Connect by” box. If USB, select first found or specify a local ID. If Ethernet, specify the IP Address.
These values will be used for programming and everything else.
Click on “Get Version Numbers”, to find out the current firmware versions on the device. Then use the provided Internet link to go to
labjack.com and check for more recent firmware. Download firmware files to the …\LabJack\LJSelfUpgrade\upgradefiles\
directory.
Click the Browse button and select the upgrade file to program. Based on the file name, the application will determine whether the
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Comm or Control processor is to be programmed.
Click the Program button to begin the self-upgrade process.
Figure 1-4. Self-Upgrade Application
If problems are encountered during programming, try the following:
1. Unplug the UE9, wait 5 seconds then reconnect the UE9. Click OK then press program again.
2. If step 1 does not fix the problem unplug the UE9 and watch the Control and Control LEDs while plugging the UE9 back in.
Follow the following steps based on the Comm and Control LEDs' activity.
1. If the Comm LED blinks several times and the Control LED is blinking rapidly (flash mode), connect a jumper
between FIO0 and SCL, then unplug the UE9, wait 5 seconds and plug the UE9 back in. Try programming again
(disconnect the jumper before programming).
2. If the Comm LED blinks several times and the Control LED has no activity, connect a jumper between FIO1 and
SCL, then unplug the UE9, wait 5 seconds and plug the UE9 back in. Try programming again (disconnect the jumper
before programming).
3. If the Comm LED has no activity, the UE9's Comm processor is not starting properly. Please restart your computer
and try programming again.
3. If there is no activity from the UE9's LEDs after following the above steps, please contact support.
2 - Hardware Description
The UE9 has 3 different I/O areas:
Communication Edge,
Screw Terminal Edge,
DB Edge.
The communication edge has a USB type B connector (with
black cable connected in Figure 2-1), a 10Base-T Ethernet
connector (with yellow cable connected in Figure 2-1), and two
entry points for external power (screw-terminals or power jack).
The screw terminal edge has convenient connections for 4
analog inputs, both analog outputs, and 4 flexible digital I/O
(FIO). The screw terminals are arranged in blocks of 4, with each
block consisting of Vs, GND, and two I/O. Also on this edge are
two LEDs associated with the two processors in the UE9.
The DB Edge has 2 D-sub type connectors: a DB37 and DB15.
The DB37 has some digital I/O and all the analog I/O. The DB15
has 12 additional digital I/O.
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Figure 2-1. LabJack UE9
2.1 - USB
For information about USB installation, see Section 1.
The UE9 has a full-speed USB connection compatible with USB version 1.1 or 2.0. This connection can provide communication
and power (Vusb), but it is possible that some USB ports will not be able to provide enough power to run the UE9 at all speeds.
Certain low power USB ports can be limited to 100 milliamps, and some power modes of the UE9 use more than 100 milliamps.
A USB hub with a power supply (self-powered) will always provide 500 milliamps for each port.
USB ground is connected to the UE9 ground, and USB ground is generally the same as the ground of the PC chassis and AC
mains. In this case, the UE9 is not electrically isolated when the USB cable is connected.
The details of the UE9 USB interface are handled by the high level drivers (Windows LabJackUD DLL), so the following
information is really only needed when developing low-level drivers.
The LabJack vendor ID is 0×0CD5. The product ID for the U3 is 0×0009.
The USB interface consists of the normal bidirectional control endpoint 0 and two bidirectional bulk endpoints: Endpoint 1 and
Endpoint 2. Endpoint 1 consists of a 16 byte OUT endpoint (address = 0x01) and a 16 byte IN endpoint (address 0x81). Endpoint
2 consists of a 64 byte OUT endpoint (address = 0x02) and a 64 byte IN endpoint (address = 0x82).
Commands can be sent on either endpoint, and the response will be sent on the same endpoint, except that stream data is always
transferred on IN Endpoint 2, regardless of whether the stream start command was sent on OUT Endpoint 1 or 2.
Commands can be sent on both endpoints at the same time, but as with any connection on the UE9, do not send a second
command on an endpoint until after receiving the response to the first command.
Except for reading stream data, always write and read the actual number of bytes in the command and response. If the size is not
an even multiple of the endpoint size a short packet will be transferred. In general, small transfers will be faster on Endpoint 1 and
large transfers will be faster on Endpoint 2, but the time differences are small if any, and it is normal to do all communication
besides reading stream data on Endpoint 1. The main reason for the different endpoints is to simplify calling command/response
functions while a stream is in progress.
USB stream data is a special case where each 46-byte data packet is padded with 2 zeros on the end (not part of the protocol),
and then 4 of these 48-byte blocks are grouped together and sent in 3 transfers over the 64-byte endpoint. The host will generally
read stream data over USB in multiples of 192 bytes (64 samples). This means that at low scan rates there could be a long time
between reads and latency will be high, but this can be improved by oversampling.
The USB transceiver on the UE9 has a 128 byte hardware buffer on Endpoint 2. If the UE9 stream data buffer has one or more
StreamData packets available, they are moved to the USB buffer to await a read by the host. Once placed in this USB buffer, the
data cannot be removed (e.g. by a FlushBuffer command). To avoid confusion on future communication on Endpoint 2, this buffer
should always be emptied after streaming.
One way to empty this buffer is to continue reading data after StreamStop, until there is no more (the read times out). This should
not require a long timeout as the data is not being acquired, but simply waiting to be retrieved from the UE9 FIFO buffer.
Another option is to follow the StreamStop command with a FlushBuffer command. Then just try to read the last 128 bytes that
could still be in the USB buffer.
A third option is to do a StreamStop (and a FlushBuffer if desired), and then do not attempt to empty the USB buffer, but always
discard the first two StreamData packets after StreamStart.
2.2 - Ethernet
The UE9 has a 10Base-T Ethernet connection. This connection only provides communication, so power must be provided by an
external power supply or USB connection.
UE9 commands (Section 5) can all be sent using TCP, except for DiscoveryUDP. All commands, except stream related
commands, can also be sent using UDP.
The Ethernet connection on the UE9 has 1500 volts of galvanic isolation. As long as the USB cable is not connected, the overall
isolation level of the UE9 will be determined by the power supply. All power supplies shipped by LabJack Corporation with the
UE9 have at least 500 volts of isolation.
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See a note about power-over-Ethernet (POE) in Section 2.3.
The UE9 has a 10Base-T Ethernet connection. This connection only provides communication, so power must be provided by an
external power supply or USB connection. The UE9 ships with an Ethernet patch cable that would normally be used to connect to a
hub or switch. A direct connection from the UE9 to a computer might require a crossover cable (not included), but often the
network interface card (NIC) on modern computers is capable of automatically detecting the signal orientation and will work with
either cable type (patch or crossover).
The LEDs on a switch/hub/NIC can be used to determine if you have an electrically valid connection. An orange LED is often used
to indicate a good 10Base-T connection, but consult the manual for the switch/nub/NIC to be sure. In the case of a direct
connection between PC and UE9, if Windows says “A network cable is unplugged” or similar, it suggests that the UE9 is not
powered or the wrong type of cable is connected.
Complex networks might require the assistance of your network administrator to use the UE9, but the following information is often
sufficient for basic networks.
One basic requirement for TCP communication is that the UE9’s IP address must be part of the subnet and not already used.
Open a command prompt window and type “ipconfig” to see a listing of the IP address and subnet mask for a particular PC. If the
PC shows a subnet mask of 255.255.255.0, that means it can only talk to devices with the same first 3 bytes of the IP address.
The default IP address of the UE9 is 192.168.1.209, which will generally work on a network using the 192.168.1.* subnet (unless
another device is already using the .209 address). If the IP address of the UE9 needs to be changed, the easiest way is via USB
with the LJControlPanel application.
LJControlPanel and Ping (open a command prompt window and type “ping 192.168.1.209”) are useful utilities for testing basic
Ethernet communication. It is a good idea to attempt to Ping the desired IP address before connecting the UE9, to see if anything
is already using that address. A more extensive Ethernet troubleshooting utility called UE9ethertest is available. See the file
readme.txt in the UE9ethertest.zip archive for more information.
2.3 - Vext (Screw Terminals and Power Jack)
There are two connections for an external power supply (Vext): a two-pole screw terminal or a 2.1 mm center-positive power jack.
These connections are electrically the same, so generally only one is used at a time.
The nominal power supply voltage for the UE9 is 5 volts. Power can be provided from the USB connection (Vusb) or an external
power supply (Vext). The UE9 has an internal semiconductor switch that automatically selects between Vusb and Vext. Both power
sources can be connected at the same time, and either can be connected/disconnected at any time. As long as one supply
remains valid, the UE9 will operate normally. If both Vusb and Vext are connected and valid, the internal switch will select Vext.
The UE9 power supply requirement is nominally 5 volts at <200 mA (see Appendix A). This is generally provided by a wall-wart or
wall-transformer type of supply. A supply capable of 500 mA is recommended. The power jack connector is 2.1 × 5.5 mm, center
positive. A linear (regulated) or switching supply is acceptable. Switching supplies are generally noisier than linears, but the UE9
is not particularly sensitive to power supply noise, and most users will not notice any difference. One option is the CUI
EMSA050120K-P5P-SZ available from Digikey, for which you will also need a clip: EMS-AU (Australia), EMS-CC (China), EMS-
EU (Europe), EMS-UK (United Kingdom), or EMS-US (United States).
Another interesting option is a power-over-Ethernet (POE) adapter. The UE9 does not support POE itself, but there are POE
adapters that split out the data and power in such a manner that is acceptable for the UE9. These adapters consist of an injector
and splitter, and a single Ethernet cable carries data and power between the two. LabJack Corporation has done testing with the
WAPPOE unit from Linksys, which is an off-the-shelf POE adapter with the proper connections for a UE9.
2.4 - Comm and Control LEDs
There is a yellow LED associated with the Comm (communication) processor, and a green LED associated with the Control
processor.
The Comm LED flashes on reset and USB enumeration, and then only turns on when there is communication (USB/Ethernet)
traffic. This LED then turns off if there is no communication for about 200 ms.
The Control LED normally blinks continuously at about 2.5 Hz. In flash programming mode it blinks at about 8 Hz. If the LED is
blinking at about 0.5 Hz, that signifies the deprecated (no longer supported) low power mode. Those blink rates apply when the
UE9 is idle, as this LED also flashes on Control processor activity.
Normal Power-Up LED Behavior: When the USB cable is connected to the UE9 (no other connections at all and no software
running), both LEDs will start blinking. The Comm LED will blink a few times and then turn off. The Control LED will continue to
blink continuously.
2.5 - GND and SGND
The GND connections available at the screw-terminals and DB connectors provide a common ground for all LabJack functions. All
GND terminals are the same and connect to the same ground plane. This ground is the same as the ground line on the USB
connection, which is often the same as ground on the PC chassis and therefore AC mains ground. This ground is also the same
as the ground on either Vext connections (wall-wart power jack or minus screw terminals), but if an isolated supply is used, such as
the one included with the UE9, there is no common connection to AC mains ground.
SGND is located near the upper-left of the device. This terminal has a self-resetting thermal fuse in series with GND. This is often
a good terminal to use when connecting the ground from another separately powered system that could unknowingly already share
a common ground with the UE9.
The UE9 has separate ground planes on the PCB for analog and digital, but the planes are shorted together so the user only has
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to consider one common ground (GND).
See the AIN, DAC, and Digital I/O Sections for more information about grounding.
2.6 - Vs
The Vs terminals are designed as outputs for the internal supply voltage (nominally 5 volts). This will be the voltage provided from
the USB connection (Vusb) or an external power supply (Vext) as described in Section 2.3. The Vs connections are outputs, not
inputs. Do not connect a power source to Vs. All Vs terminals are the same.
2.7 - AIN
The LabJack UE9 has 14 user accessible analog inputs built-in. All the analog inputs are available on the DB37 connector, and
the first 4 are also available on the built-in screw terminals.
The analog inputs have variable resolution, where the time required per sample increases with increasing resolution. The value
passed for resolution is from 0-17, where 0-12 all correspond to 12-bit resolution, and 17 still results in 16-bit resolution but with
minimum noise. The UE9-Pro has an additional resolution setting of 18 that causes acquisitions to use the alternate high-
resolution converter (24-bit sigma-delta). Resolution is configured on a device basis, not for each channel.
The analog inputs are connected to a high impedance input buffer. The inputs are not pulled to 0.0 volts, as that would reduce the
input impedance, so readings obtained from floating channels will generally not be 0.0 volts. The readings from floating channels
depend on adjacent channels and sample rate. See Section 2.7.3.8.
When scanning multiple channels, the nominal channel-to-channel delay is specified in Appendix A, and includes enough settling
time to meet the specified performance. Some signal sources could benefit from increased settling, so a settling time parameter
is available that adds extra delay between configuring the multiplexers and acquiring a sample. The passed settling time value is
multiplied by 5 microseconds to get the approximate extra delay. This extra delay will impact the maximum possible data rates.
2.7.1 - Channel Numbers
The LabJack UE9 has 16 total built-in analog inputs. Two of these are connected internally (AIN14/AIN15), leaving 14 user
accessible analog inputs (AIN0-AIN13). The first 4 analog inputs, AIN0-AIN3, appear both on the screw terminals and on the DB37
connector. These connections are electrically the same, and the user must exercise caution only to use one connection or the
other, and not create a short circuit.
Following is a table showing the channel number to pass to acquire different readings from the internal channels (AIN14/15).
Channel#
14
Vref (~2.43 V)
128
Vref (~2.43 V)
132
Vsupply
133
Temp Sensor
15
GND
136
GND
140
Vsupply
141
Temp Sensor
Table 2.7.1-1. Internal Channels
GND and Vref connect 0.0 volts and about 2.43 volts to the internal channels. These signals come through the same input path as
channels 0-13, and thus can be used to test various things.
Vsupply connects the 5 volt supply voltage (Vs) directly to the analog to digital converter through a voltage divider that attenuates it
by 40%. The attenuation of this voltage divider is not measured during the UE9 factory calibration, but the accuracy should typically
be within 0.2%. Note that a reading from this channel returns Vs during the execution of the command, and Vs might dip slightly
while increasing a command due to the increased current draw of the UE9, thus this reading might be slightly lower than a
comparative reading from an external DMM which averages over a longer time.
The channels with the same names are identical. For instance, channel 133 or 141 both read the same internal temperature
sensor. See Section 2.7.4 for information about the internal temperature sensor.
The Mux80 accessory uses multiplexer ICs to easily expand the total number of analog inputs available from 14 to 84, or you can
connect multiplexer chips yourself.
The DB37 connector has 3 MIO lines designed to address expansion multiplexer ICs (integrated circuits), allowing for up to 112
total external analog inputs. The MAX4051A (maxim-ic.com) is a recommended multiplexer, and a convenient ±5.8 volt power
supply is available so the multiplexers can pass bipolar signals (see Vm+/Vm- discussion in Section 2.12). Note that the EB37
experiment board accessory is a convenient way to connect up to 7 MAX4051A multiplexer chips, but the UE9s ±5.8 volt supply
should still be used to power the chips as the ±10 volt supply on the EB37 is beyond the rating of the MAX4051A. Figure 2-2
shows the typical connections for a pair of multiplexers.
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Figure 2-2. Typical External Multiplexer Connections
To make use of external multiplexers, the user must be comfortable reading a simple schematic (such as Figure 2-2) and making
basic connections on a solderless breadboard (such as the EB37 Experiment Board). Initially, it is recommended to test the basic
operation of the multiplexers without the MIO lines connected. Simply connect different voltages to NO0 and NO1, connect
ADDA/ADDB/ADDC to GND, and the NO0 voltage should appear on COM. Then connect ADDA to VS and the NO1 voltage
should appear on COM.
If any of the AIN channel numbers passed to a UE9 function are in the range 16-127 (extended channels), the MIO lines will
automatically be set to output and the correct state while sampling that channel. For instance, a channel number of 28 will cause
the MIO to be set to b100 and the ADC will sample AIN1. Channel number besides 16-127 will have no affect on the MIO. The
extended channel number mapping is shown in Table 2-2.
In command/response mode, after sampling an extended channel the MIO lines remain in that same condition until commanded
differently by another extended channel or another function. When streaming with any extended channels, the MIO lines are all set
to output-low for any non extended analog channels. For special channels (digital/timers/counters), the MIO are driven to
unspecified states. Note that the StopStream can occur during any sample within a scan, so the MIO lines will wind up configured
for any of the extended channels in the scan. If a stream does not have any extended channels, the MIO lines are not affected.
UE9
MIO Multiplexed
Channel
Channels
0
16-23
1
24-31
2
32-39
3
40-47
4
48-55
5
56-63
6
64-71
7
72-79
8
80-87
9
88-95
10
96-103
11
104-111
12
112-119
13
120-127
14
128-135
15
136-143
Table 2.7.2-1. Expanded Channel Mapping
2.7.2 - Converting Binary Readings to Voltages
This information is only needed when using low-level functions and other ways of getting binary readings. Readings in volts already
have the calibration constants applied. The UD driver, for example, normally returns voltage readings unless binary readings are
specifically requested.
Following are the nominal input voltage ranges for the analog inputs.
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Gain
Max V
Min V
Unipolar
1
5.07
-0.01
Unipolar
2
2.53
-0.01
Unipolar
4
1.26
-0.01
Unipolar
8
0.62
-0.01
Bipolar
1
5.07
-5.18
Table 2.7.2-1. Nominal Analog Input Voltage Ranges
The high-resolution converter on the UE9-Pro only supports the 0-5 and +/-5 volt ranges.
The readings returned by the analog inputs are raw binary values (low level functions). An approximate voltage conversion can be
performed as:
Volts(uncalibrated) = (Bits/65536)*Span
Where span is the maximum voltage minus the minimum voltage from the table above. For a proper voltage conversion, though,
use the calibration values (Slope and Offset) stored in the internal flash on the Control processor.
Volts = (Slope * Bits) + Offset
In both cases, “Bits” is always aligned to 16-bits, so if the raw binary value is 24-bit data it must be divided by 256 before
converting to voltage. Binary readings are always unsigned integers.
Since the UE9 uses multiplexers, all channels (except 129-135 and 137-143) have the same calibration for a given input range.
See Section 5.6 for details about the location of the UE9 calibration constants
2.7.3 - Typical Analog Input Connections
A common question is “can this sensor/signal be measured with the UE9”. Unless the signal has a voltage (referred to UE9
ground) beyond the limits in Appendix A, it can be connected without damaging the UE9, but more thought is required to
determine what is necessary to make useful measurements with the UE9 or any measurement device.
Voltage (versus ground): The analog inputs on the UE9 measure a voltage with respect to UE9 ground. When measuring
parameters other than voltage, or voltages too big or too small for the UE9, some sort of sensor or transducer is required to
produce the proper voltage signal. Examples are a temperature sensor, amplifier, resistive voltage divider, or perhaps a
combination of such things.
Impedance: When connecting the UE9, or any measuring device, to a signal source, it must be considered what impact the
measuring device will have on the signal. The main consideration is whether the currents going into or out of the UE9 analog input
will cause noticeable voltage errors due to the impedance of the source. See Appendix A for the recommended maximum source
impedance.
Resolution (and Accuracy): Based on the selected input range and resolution of the UE9, the resolution can be determined in
terms of voltage or engineering units. For example, assume some temperature sensor provides a 0-10 mV signal, corresponding
to 0-100 degrees C. Samples are then acquired with the UE9 using the 0-5 volt input range and 16-bit resolution, resulting in a
voltage resolution of about 5/65536 = 76 µV. That means there will be about 131 discrete steps across the 10 mV span of the
signal, and the overall resolution is 0.76 degrees C. If this experiment required a resolution of 0.1 degrees C, this configuration
would not be sufficient. Accuracy will also need to be considered. Appendix A places some boundaries on expected accuracy, but
an in-system calibration can generally be done to provide absolute accuracy down to the INL limits of the UE9.
Speed: How fast does the signal need to be sampled? For instance, if the signal is a waveform, what information is needed: peak,
average, RMS, shape, frequency, … ? Answers to these questions will help decide how many points are needed per waveform
cycle, and thus what sampling rate is required. In the case of multiple channels, the scan rate is also considered. See Sections 3.1
and 3.2.
2.7.3.1 - Signal from the LabJack
Each analog input on the UE9 measures the difference in voltage between that input and ground (GND). Since all I/O on the UE9
share a common ground, the voltage on a digital output or analog output can be measured by simply connecting a single wire from
that terminal to an AINx terminal.
2.7.3.2 - Unpowered Isolated Signal
An example of an unpowered isolated signal would be a thermocouple or photocell where the sensor leads are not shorted to any
external voltages. Such a sensor typically has two leads. The positive lead connects to an AINx terminal and the negative lead
connects to a GND terminal.
An exception might be a thermocouple housed in a metal probe where the negative lead of the thermocouple is shorted to the
metal probe housing. If this probe is put in contact with something (engine block, pipe, …) that is connected to ground or some
other external voltage, care needs to be taken to insure valid measurements and prevent damage.
2.7.3.3 - Signal Powered by the LabJack
A typical example of this type of signal is a 3-wire temperature sensor. The sensor has a power and ground wire that connect to Vs
and GND on the LabJack, and then has a signal wire that simply connects to an AINx terminal.
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