USB-1208LS
Analog and Digital I/O

User's Guide

January 2019. Rev 5© Measurement Computing Corporation

Trademark and Copyright Information

Measurement Computing Corporation, InstaCal, Universal Library, and the Measurement Computing logo areeither trademarks or registered trademarks of Measurement Computing Corporation. Refer to the Copyrights &Trademarks section on mccdaq.com/legal for more information about Measurement Computing trademarks.
Other product and company names mentioned herein are trademarks or trade names of their respective
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© 2019 Measurement Computing Corporation. All rights reserved. No part of this publication may be
reproduced, stored in a retrieval system, or transmitted, in any form by any means, electronic, mechanical, by
photocopying, recording, or otherwise without the prior written permission of Measurement Computing
Corporation.
NoticeMeasurement Computing Corporation does not authorize any Measurement Computing Corporation product for
use in life support systems and/or devices without prior written consent from Measurement Computing
Corporation. Life support devices/systems are devices or systems that, a) are intended for surgical implantation
into the body, or b) support or sustain life and whose failure to perform can be reasonably expected to result ininjury. Measurement Computing Corporation products are not designed with the components required, and are
not subject to the testing required to ensure a level of reliability suitable for the treatment and diagnosis ofpeople.

HM USB-1208LS

2

Table of Contents
Preface

About this User's Guide ....................................................................................................................... 5
Conventions in this user's guide ......................................................................................................................... 5
Where to find more information ......................................................................................................................... 5
Chapter 1

Introducing the USB-1208LS................................................................................................................ 6
Functional block diagram ................................................................................................................................... 6
Chapter 2

Installing the USB-1208LS.................................................................................................................... 7
Unpacking........................................................................................................................................................... 7
Installing the software ........................................................................................................................................ 7
Installing the hardware ....................................................................................................................................... 7
Calibrating the hardware..................................................................................................................................... 7
Field calibration ................................................................................................................................................................ 7
Factory calibration ............................................................................................................................................................ 7

Chapter 2

Functional Details ................................................................................................................................. 8
Analog input acquisition modes ......................................................................................................................... 8
Software paced mode ........................................................................................................................................................ 8
Hardware paced mode....................................................................................................................................................... 8
BURSTIO mode ............................................................................................................................................................... 8External components .......................................................................................................................................... 8
USB connector .................................................................................................................................................................. 9
LED .................................................................................................................................................................................. 9Screw terminal wiring ....................................................................................................................................................... 9Signal connections ............................................................................................................................................ 10
Analog inputs ...................................................................................................................................................................10
Digital I/O ........................................................................................................................................................................12
Trigger input ....................................................................................................................................................................13
Counter input ...................................................................................................................................................................13
Calibration output ............................................................................................................................................................13
Power output ....................................................................................................................................................................13
Ground terminals .............................................................................................................................................................13

Accuracy ........................................................................................................................................................... 14
Mechanical drawings ........................................................................................................................................ 17
Chapter 3

Specifications ...................................................................................................................................... 18
Analog input ..................................................................................................................................................... 18
Analog output ................................................................................................................................................... 19
Digital input/output........................................................................................................................................... 20
External trigger ................................................................................................................................................. 20Counter ............................................................................................................................................................. 20
Non-volatile memory ........................................................................................................................................ 21
Power ................................................................................................................................................................ 21
General ............................................................................................................................................................. 21
Environmental .................................................................................................................................................. 21
Mechanical ....................................................................................................................................................... 22
Signal connector ............................................................................................................................................... 223

USB-1208LS User's Guide

EU Declaration of Conformity ............................................................................................................ 24

4

Preface

About this User's Guide
This user's guide describes the Measurement Computing USB-1208LS data acquisition device and lists device
specifications.

Conventions in this user's guide
For more information
Text presented in a box signifies additional information related to the subject matter.
Caution! Shaded caution statements present information to help you avoid injuring yourself and others,
damaging your hardware, or losing your data.
bold text

Bold text is used for the names of objects on a screen, such as buttons, text boxes, and check boxes.

italic text

Italic text is used for the names of manuals and help topic titles, and to emphasize a word or phrase.

Where to find more information
Additional information about USB-1208LS hardware is available on our website at www.mccdaq.com. You canalso contact Measurement Computing Corporation with specific questions.


Knowledgebase: kb.mccdaq.com
Tech support form: www.mccdaq.com/support/support_form.aspx
Email: techsupport@mccdaq.com
Phone: 508-946-5100 and follow the instructions for reaching Tech Support

For international customers, contact your local distributor. Refer to the International Distributors section on our
website at www.mccdaq.com/International.

5Chapter 1

Introducing the USB-1208LS
The USB-1208LS features eight analog inputs, two 10-bit analog outputs, 16 digital I/O connections, and one
32-bit external event counter.
The analog inputs are software configurable for either eight 11-bit single-ended inputs, or four 12-bit
differential inputs. An on-board industry standard 82C55 programmable peripheral interface chip provides the
16 digital I/O lines in two 8-bit ports. You can configure each port independently for either input or output.
The USB-1208LS is powered by the +5 volt USB supply from your computer; no external power is required.
I/O connections are made to the device screw terminals.
The USB-1208LS device is compatible with both USB 1.1 and USB 2.0 ports. The speed of the device may belimited when using a USB 1.1 port due to the difference in transfer rates on the USB 1.1 versions of the
protocol (low-speed and full-speed).

Functional block diagram
USB-1208LS functions are illustrated in the block diagram shown here.

Figure 1. Functional block diagram

6

Chapter 2

Installing the USB-1208LS
UnpackingAs with any electronic device, you should take care while handling to avoid damage from static
electricity. Before removing the device from its packaging, ground yourself using a wrist strap or by simply
touching the computer chassis or other grounded object to eliminate any stored static charge.
Contact us immediately if any components are missing or damaged.

Installing the software
Refer to the MCC DAQ Quick Start and the USB-1208LS product page on our website for information about
the software supported by the USB-1208LS.
Install the software before you install your device
The driver needed to run the USB-2416 is installed with the software. Therefore, you need to install thesoftware package you plan to use before you install the hardware.

Installing the hardware
Be sure you are using the latest system software
Before installing the device, run Windows Update to update your system with the latest HID and USB drivers.
To connect the USB-1208LS to your system, turn your computer on, and connect the USB cable to a USB port
on your computer or to an external USB hub that is connected to your computer. The USB cable provides powerand communication to the device. When you connect the USB-1208LS for the first time, a Found New
Hardware dialog opens when the operating system detects the device. Another dialog identifies theUSB-1208LS as a USB Human Interface Device. When this dialog closes the installation is complete. The
device LED should blink and then remain on, to indicate that communication is established between the device
and your computer.
If the LED turns off
If the LED is on but then turns off, the computer has lost communication with the USB-1208LS. To restore
communication, disconnect the USB cable from the computer, and then reconnect it. This should restore
communication, and the LED should turn back on.

Calibrating the hardware
Field calibration
The USB-1208LS supports field calibration. Calibrate the device using InstaCal whenever the ambient
temperature changes by more than ±10 °C from the last calibration.

Factory calibration
The Measurement Computing Manufacturing Test department performs the initial factory calibration. Contact
Measurement Computing for details about how to return your device and have it calibrated to the factory
specifications.

7

Chapter 2

Functional Details
Analog input acquisition modes
The USB-1208LS can acquire analog input data in three different modes – software paced, hardware paced, and
BURSTIO.

Software paced mode
You acquire one analog sample at a time in software paced mode. You initiate the A/D conversion by calling asoftware command. The analog value is converted to digital and returned to the computer. You can repeat thisprocedure until you have the total number of samples that you want from one channel.
Software pacing is limited by the 20 mS round-trip requirement of a USB interrupt-type endpoint operation.
The maximum throughput sample rate in software paced mode is 50 S/s.

Hardware paced mode
You acquire data from up to eight channels in continuous scan mode. The analog data is continuously acquired,converted to digital values, and written to an on-board FIFO buffer until you stop the scan. The FIFO buffer isserviced in blocks as the data is transferred from the USB-1208LS to the memory buffer on your computer.
The maximum continuous scan rate of 1.2 kS/s is an aggregate rate. The total acquisition rate for all channels
cannot exceed 1.2 kS/s. You can acquire data from one channel at 1.2 kS/s, two channels at 600 S/s and fourchannels at 300 S/s. You can start a continuous scan with either a software command or with an external
hardware trigger event.

BURSTIO mode
In BURSTIO mode, you acquire data using the full capacity of the USB-1208LS 4 k sample FIFO. You caninitiate a single acquisition sequence of up to 4096 samples channels by either a software command or an
external hardware trigger. Captured data is read from the FIFO and transferred to a user buffer in the host PC.
BURSTIO scans are limited to the depth of the on-board memory, as the data is acquired at a rate faster than it
can be transferred to the computer. The maximum sampling rate is an aggregate rate. The maximum rates thatyou can acquire data using burst scan mode is 8 kS/s divided by the number of channels in the scan.

External components
The USB-1208LS external components are shown in Figure 2.

1
2

Screw terminal pins 21 to 40
LED

3
4

Screw terminal pins 1 to 20
USB connector

Figure 2. USB-1208LS external components

8USB-1208LS User's Guide

Functional Details

USB connector
The USB connector is on the right side of the USB-1208LS housing. This connector provides +5V power andcommunication. The voltage supplied through the USB connector is system-dependent, and may be less than
5V. No external power supply is required.

LED
The LED on the front of the housing indicates the communication status of the USB-1208LS. It uses up to
5 mA of current and cannot be disabled. The table below defines the function of the LED.
LED illumination
LED state

Indication

On – steady green
Blinks continuously
Blinks three times
Blinks at a slow rate

The USB-1208LS is connected to a computer or external USB hub.
Data is being transferred.
Initial communication is established between the USB-1208LS and the computer.
The analog input is configured for external trigger. The LED stops blinking and lights
steady green when the trigger is received.

Screw terminal wiring
The screw terminals provide the following connections:









Eight analog inputs (CH0 IN to CH7 IN)
Two analog outputs (D/A OUT 0 to D/A OUT 1)
16 digital I/O connections (PortA0 to Port A7, and Port B0 to Port B7)External trigger input (TRIG_IN)
External event counter input (CTR)
Power output (PC+5 V)
Calibration output (CAL)
Ground connections (GND)

Use 16 AWG to 30 AWG wire when making connections to the screw terminals. The differential mode pinout
is shown in Figure 3.

Figure 3. Differential mode pinout

9USB-1208LS User's Guide

Functional Details

The single-ended mode pinout is shown in Figure 4.

Figure 4. Single-ended mode pinout

Signal connections
Analog inputs
You can connect up to eight analog input connections to the screw terminal containing pins 1 to 20 (CH0 IN
through CH7 IN).
You can configure the analog input channels as eight single-ended channels or four differential channels. Whenconfigured for differential mode, each analog input has 12-bit resolution. When configured for single-endedmode, each analog input has 11-bit resolution, due to restrictions imposed by the A/D converter.
Single-ended configuration
When configured for single-ended input mode, eight analog channels are available. The input signal isreferenced to signal ground (GND), and delivered through two wires:

Connect the wire carrying the signal to be measured to CH# IN.
Connect the second wire to GND.

The input range for single-ended mode is ±10V.
To perform a single-ended measurement using differential channels, connect the signal to the "CH# IN HI"
input, and ground the associated "CH# IN LO" input.
Differential configuration
When configured for differential input mode, four analog channels are available. In differential mode, the input
signal is measured with respect to the low input, and delivered through three wires:Connect the wire carrying the signal to be measured to CH# IN HI.
Connect the wire carrying the reference signal to CH# IN LO.
Connect the third wire to GND.

A low-noise precision programmable gain amplifier (PGA) is available on differential channels to provide gains
of up to 20 and a dynamic range of up to 12-bits. Differential mode input voltage ranges are ±20 V, ±10 V,±5 V, ±4 V, ±2.5 V, ±2.0 V, 1.25 V, and ±1.0 V.
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USB-1208LS User's Guide

Functional Details

In differential mode, the following two requirements must be met for linear operation:

Any analog input must remain in the −10V to +20V range with respect to ground at all times.
The maximum differential voltage on any given analog input pair must remain within the selected voltage
range.

The input [common-mode voltage + signal] of the differential channel must be in the −10 V to +20 V range inorder to yield a useful result. For example, you input a 4 V pp sine wave to CHHI, and apply the same sine
wave 180° out of phase to CHLO. The common mode voltage is 0 V. The differential input voltage swings from
4 V – (–4 V) = 8 V to –4 V – 4 V = –8V. Both inputs satisfy the –10 V to +20 V input range requirement, andthe differential voltage is suited for the ±10 V input range (see Figure 5).

Figure 5. Differential voltage example: common mode voltage of 0 V

If you increase the common mode voltage to 11 V, the differential remains at ±8 V. Although the [commonmode voltage + signal] on each input now has a range of +7 V to +15 V, both inputs still satisfy the –10 V to
+20 V input requirement (see Figure 6).

Figure 6. Differential voltage example: common mode voltage of 11V

If you decrease the common-mode voltage to –7 V, the differential stays at ±8 V. However, the solution now
violates the input range condition of -10 V to +20 V. The voltage on each analog input now swings from –3V to–11V. Voltages between –10 V and –3 V are resolved, but those below –10 V are clipped (see Figure 7).

Figure 7. Differential voltage example: common mode voltage of –7 V

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USB-1208LS User's Guide

Functional Details

Since the analog inputs are restricted to a −10 V to +20 V signal swing with respect to ground, all ranges except±20V can realize a linear output for any differential signal with zero common mode voltage and full scale signal
inputs. The ±20 V range is the exception. You cannot put −20 V on CHHI and 0 V on CHLO since this violates
the input range criteria.
The table below shows some possible inputs and the expected results.
Sample inputs and differential results
CHHI

CHLO

Result

–20 V
–15 V
–10 V
–10 V
0V
0V
+10 V
+10 V
+15 V
+20 V

0V
+5 V
0V
+10 V
+10 V
+20 V
–10 V
0V
–5 V
0

Invalid
Invalid
–10 V
–20 V
–10 V
–20 V
+20 V
+10 V
+20 V
+20 V

Information about analog signal connections
For more information about single-ended and differential inputs, refer to the Guide to DAQ Signal Connections
on our website at www.mccdaq.com/support/DAQ-Signal-Connections.aspx.)
Channel-Gain queue
The channel-gain queue feature allows you to set up a scan sequence with a unique per-channel gain setting andchannel sequence. The gain settings are stored in a channel-gain queue list that is written to local memory on
the device.
The channel-gain queue list can contain up to 8 elements in any order. An example of a four-element list is
shown in the table below.
Sample channel-gain queue list
Element

Channel

Range

0
1
2
3

CH0
CH0
CH3
CH2

BIP10V
BIP5V
BIP10V
BIP1V

When a scan begins with the gain queue enabled, the USB-1208LS reads the first element, sets the appropriate
channel number and range, and then acquires a sample. The properties of the next element are then retrieved,
and another sample is acquired. This sequence continues until all elements in the gain queue have been selected.
When the end of the channel list is detected, the sequence returns to the first element in the list. This sequence
repeats until the specified number of samples is acquired.
Carefully match the gain to the expected voltage range on the associated channel or an over range condition
may occur. Although this condition does not damage the device, it does produce a useless full-scale reading,and can introduce a long recovery time due to saturation of the input channel.

Digital I/O
You can connect up to 16 digital I/O lines to the screw terminal containing pins 21 to 40 (Port A0 to Port A7,and Port B0 to Port B7.) You can configure each digital port for either input or output.
When you configure the digital bits for input, you can use the digital I/O terminals to detect the state of any
TTL level input.
12USB-1208LS User's Guide

Functional Details

Refer to the schematic shown in Figure 8. If the switch is set to the +5 V input, Port A0 reads TRUE (1). If you
move the switch to GND, Port A0 reads FALSE.

Figure 8. Schematic showing switch detection by digital channel Port A0

Information about digital signal connections
For more information about digital signal connections and digital I/O techniques, refer to the Guide to DAQ
Signal Connections on our website at www.mccdaq.com/support/DAQ-Signal-Connections.aspx).

Trigger input
The TRIG_IN terminal is an external digital input that you can configure for either TTL level high or low.

Counter input
The CTR terminal is a 32-bit event counter that can accept frequency inputs up to 1 MHz. The internal counterincrements when the TTL levels transition from low to high.

Calibration output
The CAL terminal is an output used only to calibrate the device. Calibration is software-controlled via InstaCal.

Power output
The PC +5V terminal is a 5 volt output that is supplied by the computer. You can use this terminal to supply
power to external devices or circuitry.
Caution! The PC +5V terminal is an output. Do not connect to an external power supply or you may damage
the USB-1208LS and possibly the computer.
The maximum total output current that can be drawn from all USB-1208LS connections (power, analog anddigital outputs) is 500 mA. This maximum applies to most personal computers and self-powered USB hubs.
Bus-powered hubs and notebook computers may limit the maximum available output current to 100 mA.
Just connecting the USB-1208LS to your computer draws 20 mA of current from the USB +5 V supply. Onceyou start running applications, each DIO bit can draw up to 2.5 mA, and each analog output can draw 30 mA.
The maximum amount of +5 V current available for experimental use, over and above that required by thedevice, is the difference between the total current requirement of the USB device (based on the application),and the allowed current draw of the PC platform (500 mA for desktop PCs and self-powered hubs, or 100 mA
for bus-powered hubs and notebook computers).
With all outputs at their maximum output current, the total current requirement of the USB +5 V is:(USB-1208LS @ 20 mA) + (16 DIO @ 2.5 mA ea) + (2 AO @ 30 mA ea ) = 120 mA

For an application running on a PC or powered hub, the maximum available excess current is 500 mA−120 mA= 380 mA. This number is the total maximum available current at the PC+5V screw terminals. Cole-Parmer
highly recommends that you figure in a safety factor of 20% below this maximum current loading for yourapplications. A conservative, safe user maximum in this case would be in the 300-320 mA range.
Since laptop computers typically allow up to 100 mA, the USB-1208LS in a fully-loaded configuration may be
above that allowed by the computer. In this case, you must determine the per-pin loading in the application toensure that the maximum loading criteria is met. The per-pin loading is calculated by simply dividing the +5 V
by the load impedance of the pin in question.

Ground terminals
The GND connections are identical and provide a common ground for all device functions.
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USB-1208LS User's Guide

Functional Details

Accuracy
The overall accuracy of any instrument is limited by the error components within the system. Quite often,
resolution is incorrectly used to quantify the performance of a measurement product. While "12-bits" or "1 partin 4096" does indicate what can be resolved, it provides little insight into the quality of an absolutemeasurement. Accuracy specifications describe the actual results that can be realized with a measurement
device.
There are three types of errors which affect the accuracy of a measurement system:

offsetgain
nonlinearity.

The primary error sources in the USB-1208LS are offset and gain. Nonlinearity is small in the USB-1208LS,
and is not significant as an error source with respect to offset and gain.
Figure 9 shows an ideal, error-free, USB-1208LS transfer function. The typical calibrated accuracy of the USB1208LS is range-dependent, as explained in the Specifications chapter. We use a ±10 V range here as an
example of what you can expect when performing a measurement in this range.

Figure 9. Ideal ADC transfer function

The USB-1208LS offset error is measured at mid-scale. Ideally, a zero volt input should produce an output codeof 2048. Any deviation from this is an offset error. Figure 10 shows the USB-1208LS transfer function with anoffset error. The typical offset error specification on the ±10 V range is ±9.77 mV. Offset error affects all codes
equally by shifting the entire transfer function up or down along the input voltage axis.

14USB-1208LS User's Guide

Functional Details

The accuracy plots in Figure 10 are drawn for clarity and are not drawn to scale.

Figure 10. ADC transfer function with offset error

Gain error is a change in the slope of the transfer function from the ideal, and is typically expressed as apercentage of full-scale. Figure 11 shows the USB-1208LS transfer function with gain error. Gain error is easily
converted to voltage by multiplying the full-scale (FS) input by the error.
The accuracy plots in Figure 11 are drawn for clarity and are not drawn to scale.

Figure 11. ADC Transfer function with gain error

For example, the USB-1208LS exhibits a typical calibrated gain error of ±0.2% on all ranges. For the ±10 V
range, this would yield 10 V × ±0.002 = ±20 mV. This means that at full scale, neglecting the effect of offset forthe moment, the measurement would be within 20 mV of the actual value. Note that gain error is expressed as aratio. Values near ±FS are more affected from an absolute voltage standpoint than are values near mid-scale,
which see little or no voltage error.

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USB-1208LS User's Guide

Functional Details

Combining these two error sources in Figure 12, we have a plot of the error band of the USB-1208LS for the±10 V range. This is a graphical version of the typical accuracy specification of the product.
The accuracy plots in Figure 12 are drawn for clarity and are not drawn to scale.

Figure 12. Error band plot16

USB-1208LS User's Guide

Functional Details

Mechanical drawings

Figure 13. Circuit board (top) and enclosure dimensions

17

Chapter 3

Specifications
All specifications are subject to change without notice.
Typical for 25°C unless otherwise specified.
Specifications in italic text are guaranteed by design.

Analog input
Table 1. Analog input specifications
Parameter
A/D converter type
Input voltage range for linear operation,
single-ended mode
Input common-mode voltage range forlinear operation, differential mode
Absolute maximum input voltage
Input current (Note 1)

Conditions

Specification

CHx to GND

Successive approximation type
±10 V max

CHx to GND–10 V min, +20 V max

CHx to GND
Vin = +10 V
Vin = 0V
Vin = –10 V±40V max
70 µA typ–12 µA typ–94 µA typ
122 kΩ
8 single ended / 4 differential,
software-selectable±10V, G=2
±20V, G=1
±10V, G=2
±5V, G=4±4V, G=5±2.5V, G=8±2.0V, G=10
±1.25V, G=16
±1.0V, G=20
Software-selectable
50 S/s
1.2 kS/s
8 kS/sSoftware configurable channel, range, andgain.
12 bits, no missing codes
11 bits±0.05% typ, ±0.25% max±1 LSB typ±0.5 LSB typ±1 LSB typ
5 mA max
20 µA min, 200 nA typExternal digital: TRIG_IN

Input impedance
Number of channels
Input ranges

Single-ended mode
Differential mode

Throughput

Software paced
Hardware paced
BURSTIO to 4 K sample FIFO
Up to 8 elements

Channel gain queue
Resolution (Note 2)
CAL accuracy
Integral linearity error
Differential linearity error
Repeatability
CAL current
Trigger Source
Note 1:
Note 2:Differential
Single ended
CAL = 2.5V

SourceSink
Software-selectable

Input current is a function of applied voltage on the analog input channels. For a given input voltage, Vin, theinput leakage is approximately equal to (8.181* Vin – 12) µA.
The AD7870 converter only returns 11-bits (0 to 2,047 codes) in single-ended mode.

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USB-1208LS User's Guide

Specifications

Table 2. Accuracy, differential mode
Range

Accuracy (LSB)

±20 V
±10 V
±5 V
±4 V
±2.5 V±2 V±1.25 V
±1 V

5.1
6.1
8.1
9.1
12.1
14.1
20.1
24.1
Table 3. Accuracy, single-ended mode

Range

Accuracy (LSB)

±10 V

4.0
Table 4. Accuracy components, differential mode – all values are (±)

Range% of Reading

Gain Error at FS(mV)

Offset (mV)

Accuracy at FS (mV)

±20 V
±10 V
±5 V
±4 V
±2.5 V±2 V±1.25 V
±1 V

0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2

40
20
10
8
5
4
2.5
2

9.766
9.766
9.766
9.766
9.766
9.766
9.766
9.766

49.76629.76619.76617.76614.76613.766
12.26611.766

Table 5. Accuracy components, single-ended mode – all values are (±)
Range% of Reading

Gain Error at FS(mV)

Offset (mV)

Accuracy at FS (mV)

±10 V

0.2

20

19.53139.531

Analog output
Table 6. Analog output specifications
Parameter
D/A converter type
Resolution
Maximum output range
Number of channels
Throughput
Power on and reset voltage
Maximum voltage (Note 3)

Output current drive
Slew rate

Conditions

Specification

Software paced

No load
1 mA load
5 mA load
Each D/A OUT

PWM
10-bits, 1 in 1024
0 V to 5 V
2100 S/s single-channel mode
50 S/s dual-channel mode
Initializes to 000h codeVs
0.99 * Vs
0.98 * Vs
30 mA
0.14 V/ms typ

Note 3: Vs is the USB bus +5V power. The maximum analog output voltage is equal to Vs at no-load. V is systemdependent and may be less than 5 volts.

19USB-1208LS User's Guide

Specifications

Digital input/output
Table 7. DIO specifications
Parameter

Specification

Digital type
Number of I/O
Configuration
Pull up/pull-down configuration
Input high voltage
Input low voltage
Output high voltage (IOH = –2.5 mA)
Output low voltage (IOL = 2.5 mA)

82C55
16 – Port A0 through A7, Port B0 through B7
2 banks of 8
All pins pulled up to Vs through 47 kΩ resistors (default).
2.0 V min, 5.5 V absolute max
0.8 V max, –0.5 V absolute min
3.0 V min
0.4 V maxExternal trigger
Table 8. Trigger input specifications
Parameter

Conditions

Specification

Trigger source (Note 4)
Trigger mode

External digital
Software-selectable

Trigger latency
Trigger pulse width
Input high voltage
Input low voltage
Input leakage current

Burst
Burst

TRIG_IN
Level sensitive: user configurable for TTL levelhigh or low input.
25 µs min, 50 µs max
40 µs min
3.0 V min, 15.0 V absolute max
0.8 V max
±1.0 µA

Note 4:

TRIG_IN is protected with a 1.5 kΩ series resistor.

CounterTable 9. Counter specifications
Parameter

Specification

Counter type
Number of channels
Input source
Input type
Resolution
Schmidt trigger hysteresis
Input leakage current
Maximum input frequency
High pulse width
Low pulse width
Input low voltage
Input high voltage

Event counter1
CTR screw terminal
TTL, rising-edge triggered
32 bits
20 mV to 100 mV
±1 µA
1 MHz
500 ns min
500 ns min
0 V min, 1.0 V max
4.0 V min, 15.0 V max

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USB-1208LS User's Guide

Specifications

Non-volatile memory
Table 10. Memory specifications
Parameter

Specification

Memory size
Memory configuration

8192 bytes
Address Range

AccessDescription

0x0000 – 0x17FF
0x1800 – 0x1EFF
0x1F00 – 0x1FEF
0x1FF0 – 0x1FFF

Read/write
Read/write
Read/write
Read/write

A/D data (4K samples)
User data area
Calibration data
System data

Power
Table 11. Power specifications
Parameter
Supply current (Note 5)+5V USB power available(Note 6)
Output current (Note 7)
Note 5:Note 6:Note 7:

Conditions

Specification

Connected to self-powered hub
Connected to bus-powered hub
Connected to bus-powered hub
Connected to bus-powered hub

20 mA
4.5 V min, 5.25 V max
4.1 V min, 5.25 V max
450 mA min, 500 mA max
50 mA min, 100 mA max

This is the total current requirement for the USB-1208LS which includes up to 5 mA for the status LED.
Self-powered refers to USB hubs and hosts with a power supply. Bus-powered refers to USB hubs and hosts
without their own power supply.
This refers to the total amount of current that can be sourced from the USB +5V, analog outputs, and digital
outputs.

GeneralTable 12. General specifications
Parameter

Conditions

Specification

USB controller clock error

25 °C
0 °C to 70 °C±30 ppm max±50 ppm max
USB 1.1 low-speed
USB 1.1, USB 2.0

Device type
Device compatibility

Environmental
Table 13. Environmental specifications
Parameter

Specification

Operating temperature range
Storage temperature range
Humidity–0 °C to 70 °C–40 °C to 70 °C
0% to 90% non-condensing

21

USB-1208LS User's Guide

Specifications

Mechanical
Table 14. Mechanical specifications
Parameter

Specification

Dimensions (L × W × H)
USB cable length
User connection length

79 × 82 × 27 mm (3.10 × 3.20 × 1.05 in.)3 m (9.84 ft) max
3 m (9.84 ft) max

Signal connector
Parameter

Specification

Connector type
Wire gauge range

Screw terminal
16 AWG to 30 AWG
4-channel differential mode pinout

Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

Signal Name
CH0 IN HI
CH0 IN LO
GND
CH1 IN HI
CH1 IN LO
GND
CH2 IN HI
CH2 IN LO
GND
CH3 IN HI
CH3 IN LO
GND
D/A OUT 0
D/A OUT 1
GND
CAL
GND
TRIG_IN
GND
CTR

Pin
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40

22

Signal NamePort A0
Port A1
Port A2
Port A3
Port A4
Port A5Port A6
Port A7
GND
PC+5V
GND
Port B0
Port B1
Port B2
Port B3
Port B4
Port B5
Port B6
Port B7
GND

USB-1208LS User's Guide

Specifications

8-channel single-ended mode
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

Signal Name
CH0 IN
CH1 INGND
CH2 IN
CH3 INGND
CH4 IN
CH5 INGND
CH6 IN
CH7 INGND
D/A OUT 0
D/A OUT 1
GND
CAL
GND
TRIG_IN
GND
CTR

Pin
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40

23

Signal NamePort A0
Port A1
Port A2
Port A3
Port A4
Port A5Port A6
Port A7
GND
PC+5V
GND
Port B0
Port B1
Port B2
Port B3
Port B4
Port B5
Port B6
Port B7GND

EU Declaration of Conformity
According to ISO/IEC 17050-1:2010
Manufacturer:
Address:

Product Category:
Date and Place of Issue:
Test Report Number:

Measurement Computing Corporation
10 Commerce Way
Norton, MA 02766
USAElectrical equipment for measurement, control and laboratory use.
July 22, 2016, Norton, Massachusetts USA
EMI3733.04 / EMI5215B.08

Measurement Computing Corporation declares under sole responsibility that the productUSB-1208LS
is in conformity with the relevant Union Harmonization Legislation and complies with the essential
requirements of the following applicable European Directives:
Electromagnetic Compatibility (EMC) Directive 2014/30/EU
Low Voltage Directive 2014/35/EU
RoHS Directive 2011/65/EU
Conformity is assessed in accordance to the following standards:
EMC:
Emissions: EN 61326-1:2013 (IEC 61326-1:2012), Class A
 EN 55011: 2009 + A1:2010 (IEC CISPR 11:2009 + A1:2010), Group 1, Class A
Immunity: EN 61326-1:2013 (IEC 61326-1:2012), Controlled EM Environments EN 61000-4-2:2008 (IEC 61000-4-2:2008)
 EN 61000-4-3 :2010 (IEC61000-4-3:2010)
Safety: EN 61010-1:2010 (IEC 61010-1:2010)
Environmental Affairs:
Articles manufactured on or after the Date of Issue of this Declaration of Conformity do not contain any of therestricted substances in concentrations/applications not permitted by the RoHS Directive.

Carl Haapaoja, Director of Quality Assurance

Measurement Computing Corporation
10 Commerce Way
Norton, Massachusetts 02766(508) 946-5100
Fax: (508) 946-9500
E-mail: info@mccdaq.com
www.mccdaq.com

NI Hungary Kft
H-4031 Debrecen, Hátar út 1/A, Hungary
Phone: +36 (52) 515400
Fax: +36 (52) 515414
http://hungary.ni.com/debrecen