Table Of Contents

USB-6501 Specifications

    Last Modified: November 6, 2017


    Warranted specifications describe the performance of a model under stated operating conditions and are covered by the model warranty.

    The following characteristic specifications describe values that are relevant to the use of the model under stated operating conditions but are not covered by the model warranty.

    • Typical specifications describe the performance met by a majority of models.
    • Nominal specifications describe an attribute that is based on design, conformance testing, or supplemental testing.

    Specifications are Typical unless otherwise noted.


    Specifications are valid at 25 °C unless otherwise noted. All voltages are relative to COM unless otherwise noted.

    Digital I/O

    Number of lines







    Direction control

    Input or output, software-selectable

    Output driver type

    Active drive (push-pull) or open collector (open-drain), software selectable

    Pull-up resistor

    4.7 kΩ Vbus (nominally 5 V)

    Absolute voltage range

    -0.5 V to 5.8 V with respect to GND

    Power-on state

    Input (high impedance)

    Digital Logic Levels

    Input low voltage

    -0.3 V minimum, 0.8 V maximum

    Input high voltage

    2.0 V minimum, 5.8 V maximum

    Input leakage current

    50.0 μA maximum

    Output low voltage, open collector or active drive

    IOL = 2 mA

    0.4 V maximum

    IOL = 8.5 mA

    0.8 V maximum

    Output high voltage, active drive[1]

    IOH = -2 mA

    2.8 V minimum, 3.6 V maximum

    IOH = -8.5 mA

    2.0 V minimum, 3.5 V maximum

    Output high voltage, open collector

    IOH = -0.4 mA, nominal

    2.0 V minimum, 5.0 V maximum

    IOH = -7.5 mA, with external pull-up resistor

    2.0 V minimum


    Number of counters

    1 (P2.7 can be configured as a counter)


    32 bits

    Counter measurements

    Falling edge counting

    Maximum input frequency

    5 MHz

    Minimum high pulse width

    100 ns

    Minimum low pulse width

    100 ns

    Bus Interface

    USB specification

    USB 2.0 Full Speed (12 Mb/s)

    External Voltage

    +5 V output


    4.00 V minimum, 5.25 V maximum


    230 mA maximum

    Power Requirements


    Input voltage

    4.50 VDC to 5.25 VDC, in configured state

    Active current

    80 mA typical, 500 mA maximum

    Suspend current

    500 μA maximum, all DIO lines disconnected

    Physical Characteristics


    Without connectors

    6.35 cm × 8.51 cm × 2.31 cm (2.50 in. × 3.35 in. × 0.91 in.)

    With connectors

    8.18 cm × 8.51 cm × 2.31 cm (3.22 in. × 3.35 in. × 0.91 in.)


    84 g (3 oz)

    USB connector

    USB series B receptacle (1)

    I/O connectors


    16-position (screw terminal) plug headers (2)

    Screw terminal wiring

    16 AWG to 28 AWG copper conductor wire with 10 mm (0.39 in.) of insulation stripped from the end

    Torque for screw terminals

    0.22 N · m to 0.25 N · m (2.0 lb · in. to 2.2 lb · in.)

    Figure 1. USB-6501 Dimensions

    If you need to clean the module, wipe it with a dry towel.

    Safety Voltages

    Connect only voltages that are within these limits.

    Channel-to-COM (one channel)

    ±30 V max, Measurement Category I

    Channels-to-COM (one port, all channels)

    ±8.9 V max, Measurement Category I

    Measurement Category I is for measurements performed on circuits not directly connected to the electrical distribution system referred to as MAINS voltage. MAINS is a hazardous live electrical supply system that powers equipment. This category is for measurements of voltages from specially protected secondary circuits. Such voltage measurements include signal levels, special equipment, limited-energy parts of equipment, circuits powered by regulated low-voltage sources, and electronics


    Do not use this module for connection to signals or for measurements within Measurement Categories II, III, or IV


    Measurement Categories CAT I and CAT O (Other) are equivalent. These test and measurement circuits are not intended for direct connection to the MAINS building installations of Measurement Categories CAT II, CAT III, or CAT IV.


    Temperature (IEC 60068-2-1 and IEC 60068-2-2)


    0 °C to 55 °C


    -40 °C to 85 °C

    Humidity (IEC 60068-2-56)


    5% to 90% RH, noncondensing


    5% to 90% RH, noncondensing

    Pollution Degree (IEC 60664)


    Maximum altitude

    2,000 m

    Indoor use only.

    Hazardous Locations

    This device is not certified for use in hazardous locations.


    This product is designed to meet the requirements of the following electrical equipment safety standards for measurement, control, and laboratory use:

    • IEC 61010-1, EN 61010-1
    • UL 61010-1, CSA C22.2 No. 61010-1

    For UL and other safety certifications, refer to the product label or the Online Product Certification section.

    Electromagnetic Compatibility

    This product meets the requirements of the following EMC standards for electrical equipment for measurement, control, and laboratory use:

    • EN 61326-1 (IEC 61326-1): Class A emissions; Basic immunity
    • EN 55011 (CISPR 11): Group 1, Class A emissions
    • EN 55022 (CISPR 22): Class A emissions
    • EN 55024 (CISPR 24): Immunity
    • AS/NZS CISPR 11: Group 1, Class A emissions
    • AS/NZS CISPR 22: Class A emissions
    • FCC 47 CFR Part 15B: Class A emissions
    • ICES-001: Class A emissions

    In the United States (per FCC 47 CFR), Class A equipment is intended for use in commercial, light-industrial, and heavy-industrial locations. In Europe, Canada, Australia and New Zealand (per CISPR 11) Class A equipment is intended for use only in heavy-industrial locations.


    Group 1 equipment (per CISPR 11) is any industrial, scientific, or medical equipment that does not intentionally generate radio frequency energy for the treatment of material or inspection/analysis purposes.


    For EMC declarations and certifications, and additional information, refer to the Online Product Certification section.

    CE Compliance

    This product meets the essential requirements of applicable European Directives as follows:

    • 2006/95/EC; Low-Voltage Directive (safety)
    • 2004/108/EC; Electromagnetic Compatibility Directive (EMC)

    Online Product Certification

    Refer to the product Declaration of Conformity (DoC) for additional regulatory compliance information. To obtain product certifications and the DoC for this product, visit, search by model number or product line, and click the appropriate link in the Certification column.

    Environmental Management

    NI is committed to designing and manufacturing products in an environmentally responsible manner. NI recognizes that eliminating certain hazardous substances from our products is beneficial to the environment and to NI customers.

    For additional environmental information, refer to the Minimize Our Environmental Impact web page at This page contains the environmental regulations and directives with which NI complies, as well as other environmental information not included in this document.

    Waste Electrical and Electronic Equipment (WEEE)

    EU Customers  

    At the end of the product life cycle, all NI products must be disposed of according to local laws and regulations. For more information about how to recycle NI products in your region, visit



    National Instruments符合中国电子信息产品中限制使用某些有害物质指令(RoHS)。关于National Instruments中国RoHS合规性信息,请登录。(For information about China RoHS compliance, go to

    • 1 The total current sourced by all DO lines simultaneously should not exceed 65 mA.

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