Measurement Computing USB-DIO24 User manual

USB-DIO24/37
24-Channel Digital I/O USB Device
User's Guide
May 2019. Rev 4
© Measurement Computing Corporation

HM USB-DIO24_37.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 .......................................................................................................................4
What you will learn from this user's guide .........................................................................................................4
Conventions in this user's guide .........................................................................................................................4
Where to find more information.........................................................................................................................4
Chapter 1
Introducing the USB-DIO24/37.............................................................................................................5
Overview: USB-DIO24/37 features....................................................................................................................5
Functional block diagram ...................................................................................................................................5
Chapter 2
Installing the USB-DIO24/37.................................................................................................................6
Unpacking...........................................................................................................................................................6
Installing the software ........................................................................................................................................6
Installing the hardware .......................................................................................................................................6
Connecting the board for I/O operations ............................................................................................................6
Connectors and cables....................................................................................................................................................... 6
Field wiring, signal termination and conditioning ............................................................................................................ 7
Chapter 3
Functional Details .................................................................................................................................8
Components ........................................................................................................................................................8
37-pin I/O connector......................................................................................................................................................... 8
USB connector.................................................................................................................................................................. 9
LED .................................................................................................................................................................................. 9
Pull-up resistors ................................................................................................................................................................ 9
Power consumption ............................................................................................................................................9
Mechanical Drawings .......................................................................................................................................10
Chapter 4
Specifications......................................................................................................................................11
Digital input/output...........................................................................................................................................11
Counter .............................................................................................................................................................11
Data transfer rates.............................................................................................................................................12
Power................................................................................................................................................................12
General .............................................................................................................................................................12
Environmental ..................................................................................................................................................12
Mechanical .......................................................................................................................................................13
Main connector and pinout ...............................................................................................................................13
Declaration of Conformity ..................................................................................................................14

4
Preface
About this User's Guide
What you will learn from this user's guide
This user's guide explains how to install, configure and use the USB-DIO24/37 digital I/O board. This user's
guide also refers you to related documents available on our web site and to technical support resources.
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 the 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-201 hardware is available on our website at www.mccdaq.com. You can
also contact Measurement Computing Corporation with specific questions.
Knowledgebase: kb.mccdaq.com
Tech support form: www.mccdaq.com/support/support_form.aspx
Email: [e-mail]
Phone: [phone] 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-DIO24/37
Overview: USB-DIO24/37 features
This manual explains how to install, configure and use the USB-DIO24/37 digital I/O board. You can use this
board in a variety of digital applications to control logic devices such as switches, gauges, relays, pumps, and
sensors.
The USB-DIO24/37 is a USB 2.0 low-speed device supported under popular Microsoft®Windows®operating
systems. It is designed for USB 1.1 ports and is fully compatible with both USB 1.1 and USB 2.0 ports.
The USB-DIO24/37 features 24 bits of digital I/O and one 32-bit external event counter. The device is powered
by the +5 volt USB supply. No external power is required. All I/O connections are made to a 37-pin connector.
Digital channels are pulled up to +5V with 47 kΩresistors.
An on-board industry standard 82C55 programmable peripheral interface chip provides the 24 discrete digital
I/O lines in four ports. You configure each digital port independently for either input or output.
The USB-DIO24/37 board is completely plug-and-play, with no jumpers or switches to set. All board addresses
are set by the system's plug-and-play software.
Functional block diagram
USB-DIO24/37 functions are illustrated in the block diagram shown here.
Figure 1. USB-DIO24/37 functional block diagram

6
Chapter 2
Installing the USB-DIO24/37
Unpacking
As 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-DIO24/37 product page on our website for information about
the software supported by the USB-DIO24/37.
Install the software before you install your device
The driver needed to run the USB-DIO24/37 is installed with the software. Therefore, you need to install the
software package you plan to use before you install the hardware.
Installing the hardware
To connect the USB-DIO24/37 to the system, connect the USB cable to an available USB port on the computer
or to an external USB hub connected to the computer.
When you connect the USB-DIO24/37 for the first time, multiple Found New Hardware popup balloons open
when the operating system detects the device. When installation is complete, the USB LED should flash and
then remain on. This indicates that communication is established between the USB-DIO24/37 and your
computer.
If the USB LED turns off
If the USB LED is on but then turns off, the computer has lost communication with the USB-DIO24/37. To
restore communication, disconnect the USB cable from the computer, and then reconnect it. This should restore
communication, and the USB LED should turn back on.
Caution! Do not disconnect any device from the USB bus while the computer is communicating with the
USB-DIO24/37, or you may lose data and/or your ability to communicate with the
USB-DIO24/37.
Connecting the board for I/O operations
Connectors and cables
The table below lists the board I/O connector type and compatible cables for use with the USB-DIO24/37.
Board connectors, cables, and accessory equipment
Connector type
37-pin D-type connector
Compatible cables
C37FF-x unshielded ribbon cable. x = length in feet

USB-DIO24/37 User's Guide Installing the USB-DIO24/37
7
Figure 2. Connector pinout
Information on signal connections
General information regarding signal connection and configuration is available in the Guide to DAQ Signal
Connections (available for download from www.mccdaq.com/support/DAQ-Signal-Connections.aspx.)
Figure 3. C37FF-x cable
Field wiring, signal termination and conditioning
Refer to the product page at www.mccdaq.com/usb-data-acquisition/USB-DIO24-Series.aspx for compatible
products to use with the USB-DIO24/37.
20
1
37
19
20
1
37
19
The red stripe
identifies pin # 1

8
Chapter 3
Functional Details
Components
The USB-DIO24/37 has the following components, as shown in Figure 5.
37-pin I/O connector
USB connector
LED
Figure 4. USB-DIO24/37 components
37-pin I/O connector
The 37-pin connector provides 24 digital I/O, one counter, six ground, and two 5V power connections.
The digital I/O is configured as two 8-bit and two 4-bit ports based on the 82C55 specification. Configure
each port independently for input (default) or output.
The CTR signal is the input to the 32-bit external event counter. The internal counter increments when the
digital input level transitions from low to high and can count frequencies of up to 1 MHz.
The six ground (GND) connections are identical and provide a common ground for all device functions.
The two power connections draw power from the USB connector. The +5 pin is a +5 volt output that is
supplied by the computer.
Caution! The +5 V pin is an output. Do not connect to an external power supply or you may damage the
USB-DIO24/37 and possibly the computer

USB-DIO24/37 User's Guide Functional Details
9
USB connector
The USB connector provides +5 V power and communication. The voltage supplied through the USB connector
is system-dependent, and may be less than 5 V. No external power supply is required.
LED
The LED indicates the communication status of the USB-DIO24/37. It uses up to 5 mA of current and cannot be
disabled. The table below explains the function of the USB-DIO24/37 LED.
LED Illumination
LED status Description
Steady green
The USB-DIO24/37 is connected to a computer or external USB hub.
Blinks continuously
Data is being transferred.
Blinks three times
Initial communication is established between the USB-DIO24/37 and the computer.
Pull-up resistors
Each digital port has an internal 47 kΩpull-up resistor network. All digital pins are pulled up to +5 V (high
logic level) on power up and reset.
Power consumption
The maximum total output current that can be drawn from all USB-DIO24/37 connections (power and digital
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.
Once you start running applications with the USB-DIO24/37, each DIO bit can draw up to 2.5 mA. The
maximum amount of +5V current available for external use, over and above that required by the USB-
DIO24/37, is the difference between the total current requirement of the USB-DIO24/37 (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, you can calculate the total current requirement of the USB-
DIO24/37 +5 V as follows:
(USB-DIO24/37 @ 40 mA) + (24 DIO @ 2.5 mA ea) = 100 mA
For an application running on a PC or powered hub, this value yields a maximum user current of
500 mA−100 mA = 400 mA. This number is the total maximum available current at the +5 output pins.
Measurement Computing highly recommends that you figure in a safety factor of 20% below this maximum
current loading for your applications. A conservative, safe user maximum in this case would be 320 mA.
Since laptop computers typically allow up to 100 mA, the USB-DIO24/37 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
to ensure 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.

USB-DIO24/37 User's Guide Functional Details
10
Mechanical Drawings
Figure 5. Circuit board dimensions

11
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.
Digital input/output
Table 1. Digital I/O specifications
Parameter Specification
Digital type
82C55
Number of I/O
24 (Port A Bit 0 through Port C Bit7)
Configuration
2 banks of 8 and 2 banks of 4, or 3 banks of 8
Pull up/pull-down configuration All pins pulled up to Vs via 47 kΩresistors (default). Selection available for
pull down to ground. Hardware selectable via zero Ωresistor.
Input high voltage
2.0 V min, 5.5 V absolute max
Input low voltage
0.8 V max, –0.5 V absolute min
Output high voltage (IOH = –2.5 mA)
3.0 V min
Output low voltage (IOH = –2.5mA)
0.4V max
Power up / reset state
Input mode
Counter
Table 2. Counter specifications
Parameter Specification
Pin name (Note 1)
CTR
Counter type
Event counter
Number of channels 1
Input type
TTL, rising edge triggered
Input source
CTR screw terminal
Resolution
32 bits
Schmidt trigger hysteresis
20 mV to 100 mV
Input leakage current
±1 µA
Maximum input frequency
1 MHz
High pulse width
500 ns min
Low pulse width
500 ns min
Input low voltage
0 V min, 1.0 V max
Input high voltage 4.0 V min, 15.0 V max
Note 1: CTR is a Schmitt trigger input

USB-DIO24/37 User's Guide Specifications
12
Data transfer rates
Table 3. Data transfer rate specifications
Parameter Specification
Digital I/O transfer rates (software paced)
Digital input
62 port reads or single bit reads per second typ
Digital output
125port writes or single bit writes per second typ
Counter/timer read/write rates (software paced)
Counter read
62 port reads per second typ
Counter clear
125 port writes per second typ
Power
Table 4 . Power specifications
Parameter Conditions Specification
Supply current (Note 2) 20 mA typ, 40 mA max
+5V USB power available (Note3)
Connected to self-powered hub
4.5 V min, 5.25 V max
Connected to bus-powered hub
4.1 V min, 5.25 V max
Output current (Note 4)
Connected to self-powered hub
460 mA max
Connected to bus-powered hub
60 mA max
Note 2: This is the total current requirement for the USB-DIO24/37which includes up to 5 mA for the status LED.
Note 3: 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.
Note 4: This refers to the total amount of current that can be sourced from the USB +5V and digital outputs.
General
Table 5. General specifications
Parameter Conditions Specification
USB controller clock error
25 °C
±30 ppm max
0 to 70 °C
±50 ppm max
Device type
USB 1.1 low-speed
Device compatibility
USB 1.1, USB 2.0
Environmental
Table 6. Environmental specifications
Parameter Specification
Operating temperature range
0 to 70 °C
Storage temperature range
–40 to 85 °C
Humidity
0 to 90% non-condensing

USB-DIO24/37 User's Guide Specifications
13
Mechanical
Table 7. Mechanical specifications
Parameter Specification
Dimensions (L × W × H)
119 mm × 84 mm × 14 mm (4.69 × 3.31 × 0.55 in.)
USB cable length
3 m (9.84 ft) max
USB cable type
A-B cable, UL type AWM 2527 or equivalent. (min 24 AWG VBUS/GND, min
28 AWG D+/D-)
Main connector and pinout
Table 8. Connector specifications
Parameter Specification
Connector type
37-pin D-type
Compatible cables
C37FF-x unshielded ribbon cable. x = length in feet.
Table 9. Connector pinout
Pin
Signal Name
Pin
Signal Name
1
CTR
20
+5
2
NC
21
GND
3
Port B Bit 7
22
Port C Bit 7
4
Port B Bit 6
23
Port C Bit 6
5
Port B Bit 5
24
Port C Bit 5
6
Port B Bit 4
25
Port C Bit 4
7
Port B Bit 3
26
Port C Bit 3
8
Port B Bit 2
27
Port C Bit 2
9
Port B Bit 1
28
Port C Bit 1
10
Port B Bit 0
29
Port C Bit 0
11
GND
30
Port A Bit 7
12
NC
31
Port A Bit 6
13
GND
32
Port A Bit 5
14
NC
33
Port A Bit 4
15
GND
34
Port A Bit 3
16
NC
35
Port A Bit 2
17
GND
36
Port A Bit 1
18 +5 37 Port A Bit 0
19
GND

Declaration of Conformity
Manufacturer: Measurement Computing Corporation
Address: 10 Commerce Way
Norton, MA 02766
USA
Category: Electrical equipment for measurement, control and laboratory use.
Measurement Computing Corporation declares under sole responsibility that the product
USB-DIO24/37
to which this declaration relates is in conformity with the relevant provisions of the following standards or other
documents:
EU EMC Directive 89/336/EEC: Electromagnetic Compatibility, EN 61326 (1997) Amendment 1 (1998)
Emissions: Group 1, Class A
EN 55011 (1990)/CISPR 11: Radiated and Conducted emissions.
Immunity: EN61326, Annex A
IEC 61000-4-2 (1995): Electrostatic Discharge immunity, Criteria C.
IEC 61000-4-3 (1995): Radiated Electromagnetic Field immunity Criteria A.
IEC 61000-4-8 (1994): Power Frequency Magnetic Field immunity Criteria A.
Declaration of Conformity based on tests conducted by Chomerics Test Services, Woburn, MA 01801, USA in
February, 2006. Test records are outlined in Chomerics Test Report #EMI4445.06.
We hereby declare that the equipment specified conforms to the above Directives and Standards.
Carl Haapaoja, Director of Quality Assurance

Measurement Computing Corporation NI Hungary Kft
10 Commerce Way H-4031 Debrecen, Hátar út 1/A, Hungary
Norton, Massachusetts 02766 Phone: [phone]
[phone] Fax: [phone]
Fax: [phone] http://hungary.ni.com/debrecen
E-mail: [e-mail]
www.mccdaq.com