Measurement Computing us-1208fs User manual

USB-1208FS
Analog and Digital I/O
Document Revision 10A
July 2014
©Copyright 2014
User's Guide

HM USB-1208FS.docx
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Notice
Measurement 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 in
injury. 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 of
people.

3
Table of Contents
Preface
About this User's Guide .......................................................................................................................5
What you will learn from this user's guide .........................................................................................................5
Conventions in this user's guide .........................................................................................................................5
Where to find more information.........................................................................................................................5
Chapter 1
Introducing the USB-1208FS................................................................................................................6
USB-1208FS block diagram...............................................................................................................................6
Chapter 2
Installing the USB-1208FS....................................................................................................................7
What comes with your shipment?.......................................................................................................................7
Hardware .......................................................................................................................................................................... 7
Software............................................................................................................................................................................ 7
Documentation.................................................................................................................................................................. 7
Unpacking...........................................................................................................................................................7
Installing the software ........................................................................................................................................7
Installing the hardware .......................................................................................................................................7
Chapter 3
Functional Details .................................................................................................................................9
Analog input acquisition modes .........................................................................................................................9
Software paced.................................................................................................................................................................. 9
Hardware paced ................................................................................................................................................................ 9
External components ........................................................................................................................................10
USB connector.................................................................................................................................................................10
LED .................................................................................................................................................................................10
Screw terminals................................................................................................................................................................10
Signal connections............................................................................................................................................11
Analog input....................................................................................................................................................................11
Analog output ..................................................................................................................................................................14
Digital I/O........................................................................................................................................................................14
Counter input...................................................................................................................................................................15
Trigger input....................................................................................................................................................................15
SYNC I/O ........................................................................................................................................................................15
Calibration output............................................................................................................................................................16
Ground.............................................................................................................................................................................16
Power output....................................................................................................................................................................16
Accuracy...........................................................................................................................................................16
Synchronized operations...................................................................................................................................18
Mechanical drawings........................................................................................................................................19
Chapter 4
Specifications......................................................................................................................................20
Analog input.....................................................................................................................................................20
Analog output ...................................................................................................................................................22
Digital I/O.........................................................................................................................................................22
External trigger.................................................................................................................................................23
External clock input/output...............................................................................................................................23
Counter.............................................................................................................................................................24
Non-volatile memory........................................................................................................................................24
Microcontroller.................................................................................................................................................24

USB-1208FS User's Guide
4
Power................................................................................................................................................................25
General .............................................................................................................................................................25
Environmental ..................................................................................................................................................25
Mechanical .......................................................................................................................................................25
Screw terminal connector.................................................................................................................................26
Differential mode pinout..................................................................................................................................................26
Single-ended mode pinout ...............................................................................................................................................27
Declaration of Conformity..................................................................................................................28

5
Preface
About this User's Guide
What you will learn from this user's guide
This user's guide describes the Measurement Computing USB-1208FS data acquisition device and lists device
specifications.
Conventions in this user's guide
For more information
Text presented in a box signifies additional information and helpful hints related to the subject matter you are
reading.
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 the USB-1208FS is available on our website at www.mccdaq.com. You can also
contact Measurement Computing Corporation by phone, fax, or email with specific questions.
Knowledgebase: kb.mccdaq.com
Phone: [phone] and follow the instructions for reaching Tech Support
Fax: [phone] to the attention of Tech Support
Email: [e-mail]

6
Chapter 1
Introducing the USB-1208FS
The USB-1208FS-Plus is an analog input and digital I/O data acquisition device that provides the following
features:
Eight analog input channels that are software-selectable for either eight 11-bit single-ended inputs or four
12-bit differential inputs
Two 12-bit analog output channels
16 digital I/O channels that are independently-selectable as input or output in two 8-bit ports
32-bit event counter input for counting TTL pulses
External digital trigger input
Bidirectional terminal for external clocking or multi-unit synchronization
Screw terminals for field wiring connections
The USB-1208FS is powered by the 5 volt USB supply from your computer. No external power is required.
All I/O connections are made to the device screw terminals.
USB-1208FS block diagram
USB-1208FS functions are illustrated in the block diagram shown here.
Figure 1. USB-1208FS functional block diagram

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Chapter 2
Installing the USB-1208FS
What comes with your shipment?
The following items are shipped with the USB-1208FS.
Hardware
USB-1208FS
USB cable
Software
MCC DAQ Software CD
Documentation
MCC DAQ Quick Start Guide
The Quick Start Guide booklet provides an overview of the MCC DAQ software you received with the device,
and includes information about installing the software. Please read this booklet completely before installing any
software or hardware.
Unpacking
As with any electronic device, take care while handling to avoid damage from static electricity. Before
removing the USB-1208FS from its packaging, ground yourself using a wrist strap or touch either the computer
chassis or other grounded object to eliminate any stored static charge. If the device is damaged, notify
Measurement Computing Corporation immediately by phone, fax, or email.
Knowledgebase: kb.mccdaq.com
Phone: [phone] and follow the instructions for reaching Tech Support
Fax: [phone] to the attention of Tech Support
Email: [e-mail]
For international customers, contact your local distributor. Refer to the International Distributors section on our
web site at www.mccdaq.com/International.
Installing the software
Refer to the Quick Start Guide for instructions on installing the software on the MCC DAQ CD. This booklet is
available in PDF at www.mccdaq.com/PDFmanuals/DAQ-Software-Quick-Start.pdf.
Installing the hardware
Be sure you are using the latest system software
Before installing the device, run Windows Update to update your operating system with the latest HID and USB
drivers.
To connect the USB-1208FS to your system, 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-1208FS installs as a composite device with separate devices attached. When you connect the
USB-1208FS for the first time, a Found New Hardware dialog opens as each device interface is detected. This
is normal. After the device is installed its LED blinks and then remains on. This indicates that communication is
established between the USB-1208FS and your computer.

USB-1208FS User's Guide Installing the USB-1208FS
8
If the LED turns off
If communication is lost between the device and the computer, the LED turns off. To restore communication,
disconnect the USB cable from the computer and then reconnect it. This should restore communication, and the
LED should turn on.

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Chapter 3
Functional Details
Analog input acquisition modes
The USB-1208FS can acquire analog input data in either software paced or hardware paced mode.
Software paced
The USB-1208FS acquires data one analog sample at a time using software-paced mode. You initiate the A/D
conversion by calling a software command. The analog value is converted to digital and returned to the
computer. You can repeat this procedure until you have the total number of samples that you want.
The maximum sample rate in software paced mode is system-dependent.
Hardware paced
The USB-1208FS can acquire data from up to eight channels using hardware-paced mode. The analog data is
acquired and converted to digital values until you stop the scan. Data is transferred in blocks of 31 samples from
the USB-1208FS to the memory buffer on your computer.
The A/D converter is paced by either an internal or external clock source.
The maximum sample rate is an aggregate rate. The total sample rate for all channels cannot exceed 50 kS/s.
The following table lists the sample rate when scanning from one to eight channels.
Maximum per channel sample rate
# channels scanned Sample rate (kS/s)
1 50
2 25
3 16.70
4 12.50
5 10
6 8.30
7 7.14
8 6.25
You can start a hardware-paced scan with a software command. Optionally, hardware-paced scans can be
delayed by an external hardware trigger event.

USB-1208FS User's Guide Functional Details
10
External components
The external components – screw terminal banks, LED, and USB connector –are shown in Figure 2.
1 Screw terminal pins 21 to 40 3 Screw terminal pins 1 to 20
2 LED 4 USB connector
Figure 2. External components
USB connector
The USB connector provides +5V power and communication. No external power supply is required.
LED
The LED indicates the communication status; it cannot be disabled. LED states are listed in the table below.
LED behavior
LED Illumination Indication
Steady green The USB-1208FS is connected to a computer or external USB hub.
Blinks continuously Data is being transferred.
Screw terminals
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)
One external trigger input (TRIG_IN)
One external event counter input (CTR)
One SYNC I/O for external clocking and multi-unit synchronization (SYNC)
One calibration output (CAL)
One power output (PC +5 V)
Five analog ground connections (AGND) and four digital ground connections (GND)
One ground connection (GND)
Use 16 AWG to 30 AWG wire when making connections to the screw terminals. The single-ended mode pinout
is shown in Figure 3.