Measurement Computing USB-1208HS-4AO User manual

USB-1208HS-4AO
High-Speed Analog Input and Digital I/O
Document Revision 4
July 2014
© Copyright 2014
User's Guide

2
HM USB-1208HS-4AO.docx
Your new Measurement Computing product comes with a fantastic extra —
Management committed to your satisfaction!
Thank you for choosing a Measurement Computing product—and congratulations! You own the finest, and you can now enjoy
the protection of the most comprehensive warranties and unmatched phone tech support. It’s the embodiment of our mission:
To provide data acquisition hardware and software that will save time and save money.
Simple installations minimize the time between setting up your system and actually making measurements. We offer quick and
simple access to outstanding live FREE technical support to help integrate MCC products into a DAQ system.
Limited Lifetime Warranty: Most MCC products are covered by a limited lifetime warranty against defects in materials or
workmanship for the life of the product, to the original purchaser, unless otherwise noted. Any products found to be defective in
material or workmanship will be repaired, replaced with same or similar device, or refunded at MCC’s discretion. For specific
information, please refer to the terms and conditions of sale.
Harsh Environment Program: Any Measurement Computing product that is damaged due to misuse, or any reason, may be
eligible for replacement with the same or similar device for 50% of the current list price. I/O boards face some harsh
environments, some harsher than the boards are designed to withstand. Contact MCC to determine your product’s eligibility for
this program.
30 Day Money-Back Guarantee: Any Measurement Computing Corporation product may be returned within 30 days of
purchase for a full refund of the price paid for the product being returned. If you are not satisfied, or chose the wrong product by
mistake, you do not have to keep it.
These warranties are in lieu of all other warranties, expressed or implied, including any implied warranty of merchantability or
fitness for a particular application. The remedies provided herein are the buyer’s sole and exclusive remedies. Neither
Measurement Computing Corporation, nor its employees shall be liable for any direct or indirect, special, incidental or
consequential damage arising from the use of its products, even if Measurement Computing Corporation has been notified in
advance of the possibility of such damages.
Trademark and Copyright Information
Measurement Computing Corporation, InstaCal, Universal Library, and the Measurement Computing logo are either 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 companies.
© 2014 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.
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 Manual.................................................................................................................................5
Conventions........................................................................................................................................................5
Where to find more information.........................................................................................................................5
Chapter 1
Introducing the USB-1208HS-4AO ......................................................................................................6
Functional block diagram...................................................................................................................................6
Chapter 2
Installing the USB-1208HS-4AO ..........................................................................................................7
What comes with your shipment?.......................................................................................................................7
Hardware .......................................................................................................................................................................... 7
Software............................................................................................................................................................................ 7
Documentation.................................................................................................................................................................. 7
Unpacking...........................................................................................................................................................7
Installing the software ........................................................................................................................................7
Installing the hardware .......................................................................................................................................7
Calibrating the USB-1208HS-4AO ....................................................................................................................8
Chapter 3
Functional Details .................................................................................................................................9
Analog input acquisition modes .........................................................................................................................9
Software paced mode........................................................................................................................................................ 9
Hardware paced mode....................................................................................................................................................... 9
External components ..........................................................................................................................................9
Screw terminals................................................................................................................................................................10
USB connector.................................................................................................................................................................11
Activity LED ...................................................................................................................................................................11
Status LED.......................................................................................................................................................................11
Signal connections............................................................................................................................................11
Analog input....................................................................................................................................................................11
Analog output ..................................................................................................................................................................12
External clock I/O............................................................................................................................................................12
Digital I/O........................................................................................................................................................................13
Counter input...................................................................................................................................................................14
Timer output....................................................................................................................................................................14
Trigger input....................................................................................................................................................................15
Power output....................................................................................................................................................................15
Ground.............................................................................................................................................................................15
Chapter 4
Specifications......................................................................................................................................16
Analog input.....................................................................................................................................................16
Analog output ...................................................................................................................................................18
Digital input/output...........................................................................................................................................18
External trigger.................................................................................................................................................19
External clock input/output...............................................................................................................................19
Counters............................................................................................................................................................20
Timer ................................................................................................................................................................20
Memory ............................................................................................................................................................20
Power................................................................................................................................................................21
USB specifications ...........................................................................................................................................21

USB-1208HS-4AO User's Guide
4
Environmental ..................................................................................................................................................21
Mechanical .......................................................................................................................................................22
Screw terminal connector and pinout ...............................................................................................................22
Declaration of Conformity..................................................................................................................24

5
Preface
About this Manual
This document describes the USB-1208HS-4AO data acquisition device and lists device specifications.
Conventions
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-1208HS-4AO hardware 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-1208HS-4AO
The USB-1208HS-4AO is a high-speed analog input and digital I/O data acquisition device providing the
following features:
Eight 13-bit single-ended (SE) or four differential (DIFF) analog inputs
Four 12-bit analog outputs
One external clock input and one external output for analog inputs
One external clock input and one external output for analog outputs
One digital trigger input
16 individually configurable digital I/O channels
Two 32-bit counter inputs
One 32-bit timer output
Screw terminals for field wiring connections
The device is powered by the +5 volt USB supply from your computer, and requires no external power.
The USB-1208HS-4AO is a USB 2.0 high-speed device supported under popular Microsoft®Windows®
operating systems. The USB-1208HS-4AO is compatible with both USB 1.1 and USB 2.0 ports (although the
speed of the module maybe limited when using USB 1.1 ports).
Functional block diagram
USB-1208HS-4AO functions are illustrated in Figure 1.
Figure 1. USB-1208HS-4AO functional block diagram

7
Chapter 2
Installing the USB-1208HS-4AO
What comes with your shipment?
The following items are shipped with the USB-1208HS-4AO:
Hardware
USB-1208HS-4AO
USB cable
Software
MCC DAQ CD
Documentation
In addition to this hardware user's guide, you should also receive the Quick Start Guide. This 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-1208HS-4AO 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 you install the device, run Windows Update to update your operating system with the latest USB drivers.
Install the MCC DAQ software before you install your board
The driver needed to run your board is installed with the MCC DAQ software. Therefore, you need to install the
software before you install your board. Refer to the Quick Start Guide for instructions.
To connect the USB-1208HS-4AO 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 connected to your computer. The USB cable provides power
and communication to the USB-1208HS-4AO.
When you connect the USB-1208HS-4AO for the first time, a Found New Hardware dialog opens when the
operating system detects the device. The Status LED turns on; this indicates that communication is established
between the device and the computer. Refer to Figure 2 on page 9 for the location of the Status LED. When the
dialog closes, the installation is complete.

USB-1208HS-4AO User's Guide Installing the USB-1208HS-4AO
8
Caution! Do not disconnect any device from the USB bus while the computer is communicating with the
device, or you may lose data and/or your ability to communicate with the USB-1208HS-4AO..
If the Status LED turns off
The Status LED turns off if communication is lost between the device and the computer. To restore
communication, disconnect the USB cable from the computer and reconnect it. The Status LED should turn on.
Calibrating the USB-1208HS-4AO
The USB-1208HS-4AO is shipped fully calibrated. Calibration coefficients are stored in EEPROM.
Return the device to Measurement Computing Corporation when calibration is required. The normal calibration
interval is once per year.

9
Chapter 3
Functional Details
Analog input acquisition modes
The USB-1208HS-4AO can acquire analog input data in two basic modes – software paced and hardware
paced.
Software paced mode
You can acquire one analog sample at a time in software paced mode. You initiate the A/D conversion by
calling a software command. The analog value is converted to digital data and returned to the computer. You
can repeat this procedure until you have the total number of samples that you want.
The throughput sample rate in software paced mode is system-dependent, and can range from 33 S/s to
4000 S/s.
Hardware paced mode
You can acquire data from up to eight channels in hardware-paced mode. The analog data is continuously
acquired, converted to digital values, and written to an onboard FIFO buffer on the device until you stop the
scan. The FIFO buffer is serviced in blocks as the data is transferred from the USB-1208HS-4AO FIFO buffer
to the memory buffer on your computer.
The maximum sampling rate is 1 MS/s aggregate over one-to-eight channels. You can start a continuous scan
with either a software command or with an external hardware trigger event.
External components
The USB-1208HS-4AO has the following external components, as shown in Figure 2.
Screw terminal banks
LED indicators
USB connector
1 Screw terminal pins 1 to 28 4 Activity LED
2 Screw terminal pins 29 to 56 5 USB connector
3 Status LED
Figure 2. External components

USB-1208HS-4AO User's Guide Functional Details
10
Screw terminals
The differential mode pinout is shown in Figure 3.
Figure 3. Differential mode pinout
The single-ended mode pinout is shown in Figure 4.
Figure 4. Single-ended mode pinout
Use 16 AWG to 30 AWG for signal connections.

USB-1208HS-4AO User's Guide Functional Details
11
USB connector
The USB connector provides +5 V power and communication. No external power supply is required.
Activity LED
The Activity LED indicates the communication status of the USB-1208HS-4AO. It blinks when data is
transferred, and is off when the device is not communicating. This LED uses up to 10 mA of current and cannot
be disabled.
Status LED
The Status LED turns on when the device is detected and installed on the computer.
Signal connections
Analog input
You can connect up to eight analog input connections to the screw terminals labeled AIN0 through AIN7.
Analog signals are referenced to analog ground (AGND).
Single-ended mode requires two wires:
The wire carrying the signal to be measured connects to AINx.
The second wire connects to AGND.
Differential mode requires two wires plus a ground reference:
The wire carrying the positive portion of the differential signal to be measured connects to AINx.
The wire carrying the negative portion of the differential signal to be measured connects to AIN(x+1).
The analog ground reference wire connects to AGND.
The terminal configurations for single-ended and differential modes are shown in the table below.
Channel # 8 single-ended channels configuration 0 4 differential channels configuration
Vin+ Vin– Vin+ Vin–
0 AIN0 AGND AIN0 AIN1
1 AIN1 AGND AIN2 AIN3
2 AIN2 AGND AIN4 AIN5
3 AIN3 AGND AIN6 AIN7
4 AIN4 AGND - -
5 AIN5 AGND - -
6 AIN6 AGND - -
7 AIN7 AGND - -
In single-ended mode, the input voltage ranges are ±10 V, ±5 V, ±2.5 V, 0 to 10 V. In differential mode, the
input voltage ranges are ±20 V, ±10 V, and ±5 V. The voltage level on each AINx input is limited to ±14 V

USB-1208HS-4AO User's Guide Functional Details
12
Figure 5 depicts a voltage source connected to a USB-1208HS-4AO configured for SE mode.
Figure 5. Single-ended measurement connection
Figure 6 depicts a Wheatstone bridge signal source connected to a USB-1208HS-4AO configured for DIFF
mode.
Figure 6. Differential measurement connection
For more information on analog signal connections
For more information on single-ended inputs, refer to the Guide to DAQ Signal Connections (this document is
available on our web site at www.mccdaq.com/signals/signals.pdf).
Analog output
You can connect up to four analog output connections to screw terminals AOUT0 to AOUT3. Refer to Figure 4
and Figure 3 on page 10 for the location of these pins.
Each channel can be software-paced at rates up to 5,000 updates per second (system-dependent), or hardware-
paced at rates up to 1 MS/s.
Each analog output on the USB-1208HS-4AO has a fixed ±10 V output range. The outputs default to 0 V at
power up.
External clock I/O
The USB-1208HS-4AO device provides one external clock input (AICKI) and one external clock output
(AICKO) for analog inputs, and one external clock input (AOCKI) and one external clock output (AOCKO) for
analog outputs.

USB-1208HS-4AO User's Guide Functional Details
13
You can connect an external clock signal to AICKI and/or AOCKI.
When using an external clock, AICKO outputs the pulse generated from AOCKI , and AOCKO outputs the
pulse generated from AOCKI
When using the internal clock, AICKO outputs the ADC scan clock, and AOCKO outputs the DAC scan
clock.
Digital I/O
You can connect up to 16 digital I/O lines to screw terminals DIO0 through DIO15. The terminals have 47 kΩ
resistors that you can configure for pull-up or down using an internal jumper. The default configuration is
pull-down.
You can use the digital I/O terminals to detect the state of any TTL-level input. Refer to the schematic in Figure
7. If you set the switch to the +5 V input, DIO0 reads TRUE (1). If you move the switch to GND, DIO0 reads
FALSE (0).
Figure 7. Schematic showing switch detection by digital channel DIO0
Pull-up/down configuration
Each of the 16 DIO bits on the USB-1208HS-4AO has a 47 kΩ pull-up/pull-down resistor. To configure these
bits for either a +5 V pull-up or a 0 V pull-down option, you must open the USB-1208HS-4AO case to access
the three-pin jumper labeled W34.
The pull-up/pull-down voltage is common to all of the internal 47 kΩ resistors.
To open the case and set the W34 jumper, do the following.
1. Turn over the USB-1208HS-4AO and rest it on its top on a flat, stable surface.
2. Peel off the four rubber feet on the bottom of the module to access the screws.
3. Remove the four screws shown in Figure 8 from the bottom of the device.
Figure 8. Location of screws connecting bottom and top sections of case
4. Holding both the top and bottom sections of the module, turn it back over, rest it on the surface, and
carefully remove the top section of the case.
5. Set the jumper to either pull-up or pull-down (see Figure 9 and Figure 10).

USB-1208HS-4AO User's Guide Functional Details
14
Figure 9. Location of W34 jumper (default pull-down setting shown)
Figure 10. Pull-down and pull-up configurations
1. Replace the top section of the case, and then fasten it to the bottom section with the four screws.
For more information on digital signal connections
For general information regarding digital signal connections and digital I/O techniques, refer to the Guide to
DAQ Signal Connections (available on our web site at www.mccdaq.com/signals/signals.pdf).
Counter input
CTR0 and CTR1 provide connections to each 32-bit counter input channel. Each counter can count frequencies
of up to 20 MHz.
Timer output
Use the TMR terminal to connect to the pulse width modulation (PWM) timer output. You can set the following
timer output parameters through software:
pulse frequency
duty cycle (pulse width divided by the pulse period)
number of pulses to generate
time delay before starting the timer output after it's enabled
resting state of the output (idle high or idle low)
The timer can generate a pulse output with a programmable frequency range of 0.00931 Hz up to 20 MHz.

USB-1208HS-4AO User's Guide Functional Details
15
Both the period and time delay ranges are 50 ns to 107.4 seconds.
Figure 11. USB-1208HS-4AO PWM timer channel
Trigger input
The TRIG connection is an external digital trigger input. The trigger mode is software selectable for:
Level-sensitive or edge-sensitive
Rising or falling edge
High or low level
The default setting at power up is edge sensitive, rising edge.
Retrigger
The acquisition uses the trigger settings for positive edge/negative edge and level-sensitive/edge-sensitive, but
automatically re-arms the trigger after it is activated
Power output
You can use the two +5V connections to supply power to external devices or circuitry. These terminals can
output up to 285 mA. Refer to Figure 4 and Figure 3 on page 10 for the location of this pin.
Caution! The +5V terminals are outputs. Do not connect to an external power supply or you may damage
the USB-1208HS-4AO and possibly the computer.
Ground
The analog ground (AGND) connections provide a common ground for all analog I/O channels. The ground
(GND) connections provide a common ground for the digital I/O, timer/counter I/O, timer, clock I/O, and the
+5 V terminals.

16
Chapter 4
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 Condition Specification
A/D converter Analog Devices AD7329
13-bit successive approximation type
Input ranges Software-selectable
per channel
Differential: ±20 V, ±10 V, ±5 V (The voltage level on
each individual AIN input is limited to ±14 V.)
SE: ±10 V, ±5 V, ±2.5 V, 0 V to 10 V
Number of channels 4 differential, 8 single-ended
Software-selectable
Input configuration Multiplexed
Channel gain queue 8 unique consecutive elements Software-selectable range for each channel
Absolute maximum input
voltage
CHx IN to GND
±25 V max (power on)
±12 V max (power off)
Input impedance 35 MΩ min
Input bandwidth (–3 dB) All input ranges 2 MHz typ
Input leakage current ±250 nA typ
Input capacitance 32 pf typ
Offset error drift 5 ppm/°C typ
Gain error drift 25 ppm/°C typ
Maximum working voltage
(signal + common mode) ±20 V ±14 V
±10 V ±11 V
±5 V ±5.5 V
Sample rate 1 S/s to 1 MS/s, software programmable
Sample clock source Internal A/D clock or AICKI
Burst mode Software-selectable, burst rate = 1µs
Throughput Software paced 33 S/s to 4000 S/s typ, system dependent
Scan to PC memory 1 MS/s max
Resolution 13 bits
A/D no missing codes
(uncalibrated)
Differential mode
13 bits
Single-ended mode 12 bits
CMRR 60hz 74 dB typ
Crosstalk SE mode, all ranges, 250 kHz
input signal –62 dB typ
Differential mode, all ranges,
250 kHz input signal –78 dB typ

USB-1208HS-4AO User's Guide Specifications
17
Table 2. Calibrated absolute accuracy
Range Accuracy (mV)
±20 V (DIFF mode) ±9.55 typ, ±13.18 max
±10 V (DIFF mode) ±4.59 typ, ±6.23 max
±5 V (DIFF mode) ±2.25 typ, ±2.75 max
±10 V (SE mode) ±5.10 typ, ±8.06 max
±5 V (SE mode) ±2.63 typ, ±4.03 max
±2.5 V (SE mode) ±1.59 typ, ±2.70 max
0 – 10 V (SE mode) ±3.29 typ, ±5.13 max
Table 3 summarizes the noise performance for the USB-1208HS-4AO. Noise distribution is determined by
gathering 50 kS with inputs tied to ground at the user connector. Samples are gathered at the maximum
specified sample rate of 1 MS/s.
Table 3. Noise performance
Range Typical counts LSBrms
±20 V (DIFF mode) 3 0.45
±10 V (DIFF mode) 3 0.45
±5 V (DIFF mode) 3 0.45
±10 V (SE mode) 5 0.91
±5 V (SE mode) 5 0.91
±2.5 V (SE mode) 5 0.91
0 – 10 V (SE mode) 5 0.91
Table 4. Input settling time in µs, typical
Condition Range ±1 LSB ±4 LSB ±8 LSB
+ full-scale to –full-scale
channel switch, same range
to same range
±10 V 1.5 1.1 1.0
±5 V 2.1 1.1 1.0
±2.5 V 2.2 1.1 1.0
0 V to 10 V 2.6 1.1 1.0

USB-1208HS-4AO User's Guide Specifications
18
Analog output
Table 5. Analog output specifications
Parameter Condition Specification
D/A converter Texas Instruments DAC7553
Number of channels 4 independent
Resolution 12 bits
Output range Calibrated ±10 V
Uncalibrated ±10.2 V
Output transient Host PC is reset, powered on, suspended, or
a reset command is issued to device. Duration: 3 ms typ
Amplitude: 6 V p-p typ
D/A update rate Software paced 33 to 5000 S/s typ, system dependent
Hardware paced 1 MHz max (per channel)
Sample clock source Internal D/A clock or AOCKI
Monotonicity 12 bits
Output current ±3 mA max per channel
Output short-circuit
protection Output connect to GND Unlimited duration (10 mA typ)
Output coupling DC
Power up and reset state 0 V
Output noise 0.53 mV rms
Settling time (to 0.05%) 20 V output step, (RL=5 kΩ, CL=200 pf) 5 µS max
Absolute accuracy ±0.1%
Slew rate 6.7 V/µs typ
Offset error drift 10 ppm/°C typ
Gain error drift 65 ppm/°C typ
Digital input/output
Table 6. Digital I/O specifications
Parameter Specification
Digital type CMOS
Number of I/O 16
Configuration Each bit may be configured as input (power on default) or output
Pull-up configuration The port has 47 kΩ resistors configurable as pull-up or pull-down with an internal
jumper. The default setting is pull-down.
Digital I/O transfer rate
(system-paced) 33 to 8000 port reads/writes or single bit reads/writes per second typ, system dependent.
Input high voltage 2.0 V min
5.5 V absolute max
Input low voltage 0.8 V max
–0.5 V absolute min
0 V recommended min
Output high voltage 4.4 V min (IOH = –50 µA)
3.76 V min (IOH = –24 mA)
Output low voltage 0.1 V max (IOL = 50 µA)
0.44 V max (IOL = 24 mA)
Output current ±24 mA max per terminal (refer to Power section for additional information)

USB-1208HS-4AO User's Guide Specifications
19
External trigger
Table 7. External trigger specifications
Parameter Specification
Trigger source TRIG input
Trigger mode Software-selectable for edge or level sensitive, rising or falling edge, high or low level.
Power on default is edge sensitive, rising edge.
Trigger latency 1 µs + 1 clock cycle max
Trigger pulse width 100 ns min
Input type Schmitt trigger, 33 Ω series resistor and 47 kΩ pull-down to ground
Schmitt trigger hysteresis 0.4 V to 1.2 V
Input high voltage 2.2 V min
5.5 V absolute max
Input low voltage 1.5 V max
–0.5 V absolute min
0 V recommended min
External clock input/output
Table 8. External clock I/O specifications
Parameter Specification
Terminal names AICKI, AICKO, AOCKI, AOCKO
Terminal types AxCKI: Input, active on rising edge
AxCKO: Output, power on default is 0 V, active on rising edge
Terminal descriptions AxCKI: Receives sampling clock from external source
AxCKO: Outputs the internal sampling clock (D/A or A/D clock) or pulse generated from
AxCKI when in external clock mode
Input clock rate 1 MHz max
Clock pulse width AxCKI: 400 ns min
AxCKO: 400 ns min
Input type Schmitt trigger, 33 Ω series resistor, 47 kΩ pull-down to ground
Schmitt trigger hysteresis 0.4 V to 1.2 V
Input high voltage 2.2 V min
5.5 V absolute max
Input low voltage 1.5 V max
–0.5 V absolute min
0 V recommended min
Output high voltage 4.4 V min (IOH = –50 µA)
3.76 V min (IOH = –24 mA)
Output low voltage 0.1 V max (IOL = 50 µA)
0.44 V max (IOL = 24 mA)
Output current ±24 mA max per terminal (refer to Power section for additional information)

USB-1208HS-4AO User's Guide Specifications
20
Counters
Table 9. Counter specifications
Parameter Specification
Counter terminal names CTR0, CTR1
Counter type Event counter
Number of channels 2
Input type Schmitt trigger, 33 Ω series resistor, 47 kΩ pull-down to ground
Schmitt trigger hysteresis 0.4 V to 1.2 V
Input high voltage 2.2 V min
5.5 V absolute max
Input low voltage 1.5 V max
–0.5 V absolute min
0 V recommended min
Resolution 32 bits
Maximum input frequency 20 MHz
Counter read/write rates
(software paced) 33 to 8000 reads/writes per second typ, system dependent
High pulse width 25 ns min
Low pulse width 25 ns min
Timer
Table 10. Timer specifications
Parameter Specification
Timer terminal name TMR
Timer type PWM output with count, period, delay, and pulse width registers
Output value Default state is idle low with pulses high, software-selectable output invert
Internal clock frequency 40 MHz
Register widths 32 bits
High pulse width 20 ns min
Low pulse width 20 ns min
Output high voltage 4.4 V min (IOH = –50 µA)
3.76 V min (IOH = –24 mA)
Output low voltage 0.1 V max (IOL = 50 µA)
0.44 V max (IOL = 24 mA)
Output current ±24 mA max per pin (refer to Power section for additional information)
Memory
Table 11. Memory specifications
Parameter Specification
Data FIFO 4 kS analog input/4 kS analog output
Non-volatile memory 32 KB (16 KB firmware storage, 16 KB calibration/user data)