USB-1208FS-Plus
Analog and Digital I/O

User's Guide

January 2019. Rev 6© Measurement Computing Corporation

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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-1208FS-Plus.docx

Table of Contents
Preface

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

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

Installing the USB-1208FS-Plus ........................................................................................................... 7
Unpacking........................................................................................................................................................... 7
Installing the software ........................................................................................................................................ 7
Firmware updates ............................................................................................................................................... 7
Installing the hardware ....................................................................................................................................... 7
Calibrating the hardware..................................................................................................................................... 7
Chapter 3

Functional Details ................................................................................................................................. 8
Analog input acquisition modes ......................................................................................................................... 8
Software paced .................................................................................................................................................................. 8
Hardware paced ................................................................................................................................................................ 8External components .......................................................................................................................................... 9USB connector .................................................................................................................................................................. 9
LED .................................................................................................................................................................................. 9Screw terminals................................................................................................................................................................. 9Signal connections ............................................................................................................................................ 11
Analog input ....................................................................................................................................................................11
Analog output ..................................................................................................................................................................13
Digital I/O ........................................................................................................................................................................13
Counter input ...................................................................................................................................................................15
External trigger input .......................................................................................................................................................15
SYNC I/O ........................................................................................................................................................................15
Power output ....................................................................................................................................................................15
Ground .............................................................................................................................................................................15

Accuracy ........................................................................................................................................................... 15
Synchronized operations................................................................................................................................... 18
Power ................................................................................................................................................................ 18
Mechanical drawings ........................................................................................................................................ 19
Chapter 4

Specifications ...................................................................................................................................... 20
Analog input ..................................................................................................................................................... 20
Accuracy ..........................................................................................................................................................................21
Noise performance ...........................................................................................................................................................21

Analog output ................................................................................................................................................... 22
Digital input/output........................................................................................................................................... 23
External trigger ................................................................................................................................................. 23
External clock input/output............................................................................................................................... 24
Counter ............................................................................................................................................................. 25
Memory ............................................................................................................................................................ 25
Microcontroller ................................................................................................................................................. 25
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USB-1208FS-Plus User's Guide

Power ................................................................................................................................................................ 25
General ............................................................................................................................................................. 26
Environmental .................................................................................................................................................. 26
Mechanical ....................................................................................................................................................... 26
Signal connector ............................................................................................................................................... 26
Differential mode pinout ..................................................................................................................................................27
Single-ended mode pinout ...............................................................................................................................................27

EU Declaration of Conformity ............................................................................................................ 28

4

Preface

About this User's Guide
This document describes the Measurement Computing USB-1208FS-Plus data acquisition device and lists
device specifications.

Conventions
For more information
Text presented in a box signifies additional information and helpful hints related to the subject matter you arereading.
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-1208FS-Plus 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: 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
web site at www.mccdaq.com/International.

5Chapter 1

Introducing the USB-1208FS-Plus
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 configurable for either eight 11-bit single-ended inputs orfour 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 device is powered by the +5 V USB supply from the computer. No external power is required.

Functional block diagram
Device functions are illustrated in the block diagram shown here.

Figure 1. USB-1208FS-Plus functional block diagram

6

Chapter 2

Installing the USB-1208FS-Plus
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-1208FS-Plus product page on our website for information
about the software that supports the device.
Install the software before you install your device
The driver needed to run the USB-1208FS-Plus is installed with the software. Therefore, you need to install thesoftware package you plan to use before you install the hardware.

Firmware updatesYour DAQ device contains firmware that can be updated in the field if required. Firmware is available fordownload at www.mccdaq.com/firmware.aspx.We recommend that you check this page periodically to see if an
update to your device firmware is available.

Installing the hardware
To connect the device to your system, turn on your computer and connect the USB cable to an available USB
port on the computer or to an externally powered USB hub connected to the computer. Connect the other end of
the USB cable to the USB connector on the device. No external power is required.
When connected for the first time, a Found New Hardware dialog opens when the operating system detects thedevice. When the dialog box closes, the installation is complete. The LED turns on after the device issuccessfully installed.
Caution! Do not disconnect any device from the USB bus while the computer is communicating with thedevice, or you may lose data and/or your ability to communicate with the device.
If the LED turns off
If the LED is on but then turns off, the computer has lost communication with the device. To restore
communication, disconnect the USB cable from the computer and then reconnect it. This should restore
communication, and the LED should turn on.

Calibrating the hardware
The Measurement Computing Manufacturing Test department performs the initial factory calibration. Returnthe device to Measurement Computing Corporation when calibration is required. The recommended calibrationinterval is one year.
The USB-1208FS-Plus does not support field calibration.

7

Chapter 3

Functional Details
Analog input acquisition modes
The USB-1208FS-Plus can acquire analog input data in either software paced or hardware paced mode.

Software paced
The USB-1208FS-Plus acquires data one analog sample at a time using software paced mode. You initiate theA/D conversion by calling a software command. The analog value is converted to digital and returned to thecomputer. 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-Plus can acquire data from up to eight channels using hardware-paced mode. The analog datais acquired and converted to digital values until you stop the scan. Data is transferred in blocks of 32 samples
from the device 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
scannedSample rate
(kS/s)

1
2
3
4
5
6
7
8

50
25
16.70
12.50
10
8.30
7.14
6.25

You can start a hardware-paced scan with a software command. Optionally, hardware-paced scans can bedelayed by an external hardware trigger event.

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Functional Details

External components
The external components – screw terminal banks, LED, and USB connector –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. External components

USB connector
Receives the supplied USB cable. When connected to a computer or USB hub, the cable provides power andcommunication. No external power supply is required.

LED
The following table lists the behavior of the device LED.
LED state

Indication

Steady green
Blinks continuously

The device is connected to a computer or external USB hub.
Data is being transferred.

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

Eight analog input connections (CH0 IN to CH7 IN, CH0 IN HI/LO through CH3 IN HI/LO)
Two analog output connections (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 counter input (CTR)
Bidirectional terminal for external clocking or multi-unit synchronization (SYNC)
Power output (+VO)
Analog ground (AGND) and ground (GND)

Use 16 AWG to 30 AWG wire when making connections to the screw terminals.

9USB-1208FS-Plus User's Guide

Functional Details

The single-ended mode pinout is shown in Figure 3.

Figure 3. Single-ended mode pinout

The differential mode pinout is shown in Figure 4.

Figure 4. Differential mode pinout

10USB-1208FS-Plus User's Guide

Functional Details

Signal connections
Analog input
You can connect up to eight analog input connections to the screw terminal bank containing pins 1 to 20.
You can configure the analog input channels as eight single-ended channels (CH0 IN through CH7 IN) or four
differential channels (CH0 IN HI/LO through CH3 IN HI/LO). When configured for differential mode, eachanalog input has 12-bit resolution. When configured for single-ended mode, 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, the input signal is referenced to signal ground (GND) anddelivered through two wires:

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

The input range for single-ended mode is ±10 V. The single-ended mode pinout is shown in Figure 3 on page10.
Differential configuration
When configured for differential input mode, the input signal is measured with respect to the low input anddelivered 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.

The differential mode pinout is shown in Figure 4 on page 10.
Note: To perform a single-ended measurement using differential channels, connect the signal to CH# IN HI andground the associated CH# IN LO input.

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.
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 CH# IN HI and apply the same sine wave 180° out of phase toCH# IN LO. 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, and the differential
voltage is suited for the ±10 V input range (see Figure 5).

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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 [common-mode
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 11 V

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 –3 V
to –11 V. Voltages between –10 V and –3 V are resolved, but those below -10 V are clipped, as shown in
Figure 7.

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

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 CH# IN HI and 0 V on CH# IN LO,
since this violates the input range criteria.
The table below shows some possible inputs and the expected results.

12USB-1208FS-Plus User's Guide

Functional Details

Sample inputs and differential results
CH# IN HI

CH# IN LO

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

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 settings are stored in a channel-gain queue list that is written to local memory on thedevice. The gain queue can contain up to eight elements in single-ended mode, and up to four elements indifferential mode.
The elements must be unique and listed in ascending order. An example of a three-element list is shown in thetable below.
Sample channel-gain queue list
Element

Channel

Range

Gain

0
1
2

CH0
CH1
CH3

BIP10V
BIP20V
BIP4V

2
1
5

When a scan begins with the gain queue enabled, the device reads the first element, sets the appropriate channel
number, range, and gain, and then acquires a sample. The properties of the next element are then retrieved, andanother 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. The 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.
For more information about analog signal connections
For more information about analog input connections, refer to the Guide to DAQ Signal Connections (available
for download from www.mccdaq.com/support/DAQ-Signal-Connections.aspx.)

Analog output
You can connect two analog output connections to D/A OUT 0 and D/A OUT 1. Each channel can be paced at
rates up to 50,000 updates per second. The output range is 0 V to 5 V.

Digital I/O
The device has 16 DIO channels that are configured as two 8-bit ports – Port A and Port B. Port B is high drive.
You can connect up to eight DIO lines to Port A0 to Port A7 and up to eight DIO lines to Port B0 to Port B7.
You can configure each port for either input or output. The digital ports are set for input when the device ispowered on or reset.
When configured for input, the digital I/O terminals can detect the state of any TTL-level. Refer to theschematic shown in Figure 8.
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USB-1208FS-Plus User's Guide

Functional Details

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

If you set the switch to the +5V input, Port A0 reads TRUE (1). When set to GND, Port A0 reads FALSE (0).
Pull-up/down configuration
All digital I/O lines are pulled high to USB +5 V with a 47 kΩ resistor by default. You can change thepull-up/down configuration using the internal jumper labeled DIO. You must remove the device housing toaccess the jumper on the circuit board.
Complete the following steps to set the jumper for pull-up or pull-down:
1.

Unplug the device from the computer.

2.

Turn the device over and rest the top of the housing on a flat, stable surface.

Caution! The discharge of static electricity can damage some electronic components. Before removing theUSB-1208FS-Plus from its housing, ground yourself using a wrist strap or touch the computer
chassis or other grounded object to eliminate any stored static charge.
3.

Remove the three screws from the bottom of the device using a #1 Philips head screwdriver.

4.

Hold both the top and bottom sections together, turn the device over and rest it on the surface, thencarefully remove the top section of the case to expose the circuit board.
The user-configurable jumpers are labeled DIO A and DIO B. Figure 9 shows the location of each jumper on
the circuit board.

Figure 9. Pull-up/down jumper locations

5.

Set each jumper for pull-up (P/UP) or pull-down (P/DN), as shown in Figure 10. Use the jumper labeled
DIO A to configure Port A, and DIO B to configure Port B.

Figure 10. Pull-up/down jumper configuration

6.

Replace the top section of the housing and fasten it to the bottom section with the three screws.

For more information about digital signal connections
For more information on digital signal connections and digital I/O techniques, refer to the Guide to DAQ Signal
Connections (available for download from www.mccdaq.com/support/DAQ-Signal-Connections.aspx.)
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USB-1208FS-Plus User's Guide

Functional Details

Counter input
The CTR connection is input to the 32-bit external event. The internal counter increments when the TTL levels
transition from low to high. The counter can count frequencies of up to 1 MHz.

External trigger input
The TRIG_IN connection is an external trigger input that you can configure for either rising or falling edge.

SYNC I/O
The SYNC terminal is a bidirectional I/O signal that can be configured as an input (default) or an output.
Configure as an external clock input to pace the A/D conversions from an external source. The SYNC
terminal supports TTL-level input signals of up to 50 kHz.
Configure as an output to pace the conversions on a second device and acquire data from 16 channels using
one clock. For more information about synchronized operations see page 18.

Power output
The +VO connection draws power from the USB connector on the computer.
Caution! The +VO terminal is an output. Do not connect it to an external power supply or you may damage
the device and possibly the computer.

GroundThe analog ground (AGND) terminals provide a common ground for all analog channels.
The digital ground (GND) terminals provide a common ground for the digital, trigger, counter, and sync
channels and the power terminal.

Accuracy
The overall accuracy of any instrument is limited by the error components within the system. Resolution isoften incorrectly used to quantify the performance of a measurement product. While "12-bits" or "1 part in
4,096" does indicate what can be resolved, it provides little insight into the quality of an absolute measurement.
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 are offset and gain. Nonlinearity is small in each device and is not significant as anerror source with respect to offset and gain.

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USB-1208FS-Plus User's Guide

Functional Details

Figure 11 shows an ideal, error-free transfer function. The typical calibrated accuracy is range-dependent. Referto the "Accuracy specifications" on page 21 for more information. We use a ±10 V range here as an example ofwhat you can expect when performing a measurement in this range.

Figure 11. Ideal ADC transfer function

The offset error is measured at mid-scale. Ideally, a zero volt input should produce an output code of 2048. Any
deviation from this is an offset error.
Figure 12 shows an example of a transfer function with a ±9.77 mV offset error. Offset error affects all codes
equally by shifting the entire transfer function up or down along the input voltage axis.
The accuracy plots in Figure 12 are drawn for clarity and are not drawn to scale.

Figure 12. ADC transfer function with offset error

16USB-1208FS-Plus User's Guide

Functional Details

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 13 shows the 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 13 are drawn for clarity and are not drawn to scale.

Figure 13. ADC Transfer function with gain error

For example, the USB-1208FS-Plus 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, and neglecting the effectof offset, 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.
Combining these two error sources in Figure 14, we have a plot of the error band for the ±10 V range. This is agraphical version of the typical accuracy specification of the product.
The accuracy plots in Figure 14 are drawn for clarity and are not drawn to scale.

Figure 14. Error band plot17

USB-1208FS-Plus User's Guide

Functional Details

Synchronized operations
You can connect the SYNC pin of two devices together in a master/slave configuration and acquire data fromthe analog inputs of both devices using one clock.
When the SYNC pin is configured as an output, the internal A/D pacer clock signal is sent to the screw
terminal. Output the clock signal to the SYNC pin of a second device that is configured for A/D pacer input.

Power
Connecting the device to a computer draws <100 mA of current from the USB +5V supply. When runningapplications, the current that can be drawn from all device connections (analog, digital, SYNC, and +VO output
loading) is <500 mA. The maximum output current that is available at the +VO power output terminal is
100 mA.
With all outputs at their maximum output current, the USB-1208FS-Plus in a fully-loaded configuration may be
above that allowed by the computer. In this case, determine the per-pin loading in the application to ensure thatthe maximum loading criteria is met. The per-pin loading is calculated by dividing +5V by the load impedanceof the pin in question.

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Functional Details

Mechanical drawings

Figure 15. Circuit board (top) and enclosure dimensions

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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

A/D converter type
Input voltage range for linear operation

CHx to GND

Absolute maximum input voltage
Input impedance
Input current (Note 1)

Number of channels
Input ranges

Throughput (Note 2)

Specification

CHx to GND
Vin = +10 V
Vin = 0 V
Vin = –10 V
Single-ended
Differential

Software paced
Hardware paced

Channel gain queue

Resolution (Note 3)

Differential
Single-ended

Integral linearity error
Differential linearity error
Repeatability
Trigger source

Software-selectable

Pacer source

Software-selectable

Note 1:
Note 2:
Note 3:

Successive approximation type
Single-ended mode: ±10 V max
Differential mode: –10 V min, +20 V max±28 V max
122 kΩ
70 µA typ–12 µA typ–94 µA typ
8 single-ended or 4 differential; software-selectable±10 V, G=2±20 V, G=1±10 V, G=2
±5 V,
G=4
±4 V,
G=5
±2.5 V, G=8±2.0 V, G=10
±1.25 V, G=16±1.0 V, G=20
Software-selectable
250 S/s typ, PC-dependent
0.014 S/s to 50 kS/s
Software selectable. 8 elements in SE mode,
4 elements in DIFF mode.
One gain element per channel. Elements must be
unique and listed in ascending order.
12 bits, no missing codes
11 bits±1 LSB typ±0.5 LSB typ±1 LSB typ
External digital: TRIG_IN
Software-selectable Internal
 External (SYNC), rising edge triggered
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.
Maximum throughput when scanning is machine dependent.
The AD7870 converter only returns 11 bits (0 to 2,047 codes) in single-ended mode.

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USB-1208FS-Plus User's Guide

Specifications

Accuracy
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

Noise performance
Table 6. Noise performance, differential mode
Range

Typical counts

LSBrms

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

2
2
3
3
4
5
7
8

0.30
0.30
0.45
0.45
0.61
0.76
1.06
1.21

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Specifications

Table 7. Noise performance, single-ended mode
Range

Typical counts

LSBrms

±10 V

2

0.30

Analog output
Table 8. Analog output specifications
Parameter

Condition

Specification

Resolution

12-bits, 1 in 4,096

Output range

0 V to 5.0 V

Number of channels

2

Throughput (Note 4)

Software paced
Hardware paced

250 S/s single channel typ, PC dependent
50 kS/s max per channel
Initializes to 000h code

Each D/A OUT

5 mA, sourcing
0.8 V/ µs typ

Power on and reset voltage
Output drive
Slew rate
Note 4:

Maximum throughput when scanning is machine dependent.
Table 9. Analog output accuracy, all values are (±); accuracy tested at no load

Range

Accuracy (LSB)

0 V to 5.0 V

4.0 typ, 45.0 max
Table 10. Analog output accuracy components, all values are (±)

Range% of FSR

Gain Error at FS (mV)

0 V to 5.0 V

0.1 typ, 0.9 max

4.0 typ, 36.0 max

Note 5:

Offset (mV)(Note 5)
1.0 typ, 9.0 max

Accuracy at FS (mV)
4.0 typ, 45.0 max

Zero-scale offsets may result in a fixed zero-scale error producing a "dead-band” digital input code region. In
this case, changes in digital input code at values less than 0x040 may not produce a corresponding change in the
output voltage. The offset error is tested and specified at code 0x040.

22

USB-1208FS-Plus User's Guide

Specifications

Digital input/output
Table 11. Digital I/O specifications
Parameter

Specification

Digital type
Number of I/O
Configuration
Pull up/pull-down configuration

CMOS
16 (Port A0 through A7, Port B0 through B7)
2 banks of 8. Port B is high current drive.
All pins pulled up to 5V via 47 kΩ resistors (default). Change to pull-down using
internal user-configurable jumpers.
2.0 V min
5.5 V absolute max
0.8 V max
–0.5 V absolute min
0 V recommended min
4.4 V min (IOH = –20 µA)
3.84 V min (IOH = –6.0 mA)
0.1 V max (IOL = 20 µA)
0.33 V max (IOL = 6.0 mA)
4.4 V min (IOH = –50 µA)
3.76 V min (IOH = –24.0 mA)
0.1 V max (IOH = 50 µA)
0.44 V max (IOH = 24.0 mA)
Input

Input high voltage threshold
Input high voltage limit
Input low voltage threshold
Input low voltage limit
Output high voltage, Port A
Output low voltage, Port A
Output high voltage, Port B
Output low voltage, Port B
Power on and reset state

External trigger
Table 12. Digital trigger specifications
Parameter

Specification

Trigger source
Trigger mode

External digital; TRIG_IN terminal
Edge sensitive; software-selectable for CMOS compatible rising or falling edge, highor low level.
10 µs max
1 µs minSchmitt trigger, 47 kΩ pull-down to ground1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min3.1 V max
5.5 V absolute max
1.42 V typ
1.0 V min
2.0 V max
–0.5 V absolute min
0 V recommended min

Trigger latency
Trigger pulse width
Input type
Schmitt trigger hysteresis

Input high voltage threshold

Input high voltage limit
Input low voltage threshold

Input low voltage limit

23

USB-1208FS-Plus User's Guide

Specifications

External clock input/output
Table 13. External clock I/O specifications
Parameter
Terminal nameTerminal type
Direction(software-selectable)
Input clock rate
Clock pulse width

Condition

Specification
SYNC
Bidirectional
Outputs the internal A/D pacer clock
Receives A/D pacer clock from external source
50 kHz, max
1 µs min
5 µs minSchmitt trigger, 47 kΩ pull-down to ground1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min3.1 V max
5.5 V absolute max
1.42 V typ
1.0 V min
2.0 V max
–0.5 V absolute min
0 V recommended min
4.4 V min (IOH = –50 µA)
3.80 V min (IOH = –8 mA)
0.1 V max (IOL = 50 µA)
0.44 V max (IOL = 8 mA)

OutputInput (default)
Input mode
Output mode

Input type
Schmitt trigger hysteresis

Input high voltage threshold

Input high voltage limit
Input low voltage threshold

Input low voltage limit
Output high voltage
Output low voltage

24USB-1208FS-Plus User's Guide

Specifications

CounterTable 14. Counter specifications
Parameter

Specification

Pin name
Counter type
Number of channels
Input type
Input source
Resolution
Maximum input frequency
High pulse width
Low pulse width
Schmitt trigger hysteresis

CTR
Event counter
1
Schmitt trigger, 47 kΩ pull-down to ground, rising edge triggered
CTR screw terminal
32 bits
1 MHz
500 ns min
500 ns min
1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min3.1V max
5.5 V absolute max
1.42 V typ
1.0 V min
2.0 V max
–0.5 V absolute min
0 V recommended min

Input high voltage threshold

Input high voltage limit
Input low voltage threshold

Input low voltage limit

MemoryTable 15. Memory specifications
Non-volatile EEPROM

2,048 bytes (768 bytes calibration, 256 bytes user, 1,024 bytes DAQFlex)

Microcontroller
Table 16. Microcontroller specifications
TypeHigh performance 16-bit RISC microcontroller

Power
Table 17. Power specifications
Parameter

Condition

Specification

Supply current

During USB enumeration
After USB enumeration, including DIO, AO, SYNC,
and +VO output loading
After USB enumeration
After USB enumeration< 100 mA
< 500 mA

+VO power available+VO output current

25

4.5 V min, 5.25 V max
100 mA max

USB-1208FS-Plus User's Guide

Specifications

GeneralTable 18. General specifications
Parameter

Specification

Device type
Device compatibility

USB 2.0 full speed
USB 1.1, USB 2.0

Environmental
Table 19. 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

Mechanical
Table 20. 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
Table 21. Screw terminal specifications
Parameter

Specification

Connector type
Wire gauge range

Screw terminal
16 AWG to 30 AWG

26

USB-1208FS-Plus User's Guide

Specifications

Differential mode pinout
Table 22. 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
AGND
CH1 IN HI
CH1 IN LO
AGND
CH2 IN HI
CH2 IN LO
AGND
CH3 IN HI
CH3 IN LO
AGND
D/A OUT 0
D/A OUT 1
AGNDReserved
GND
TRIG_IN
SYNC
CTR

Pin description
Analog input 0+
Analog input 0–
Analog ground
Analog input 1+
Analog input 1–
Analog ground
Analog input 2+
Analog input 2–
Analog ground
Analog input 3+
Analog input 3–
Analog ground
Analog output 0
Analog output 1
Analog groundReserved for future use
GroundTrigger input
Synchronization I/OCounter input

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

Signal name
Port A0
Port A1
Port A2
Port A3
Port A4
Port A5Port A6
Port A7GND+VO
GNDPort B0
Port B1
Port B2
Port B3
Port B4
Port B5
Port B6
Port B7
GND

Pin description
Port A bit 0
Port A bit 1
Port A bit 2
Port A bit 3
Port A bit 4
Port A bit 5
Port A bit 6
Port A bit 7
GroundPower output
GroundPort B bit 0
Port B bit 1
Port B bit 2
Port B bit 3
Port B bit 4
Port B bit 5
Port B bit 6
Port B bit 7
GroundSingle-ended mode pinout
Table 23. 8-channel single-ended 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
CH1 INAGND
CH2 IN
CH3 IN
AGND
CH4 IN
CH5 INAGND
CH6 IN
CH7 INAGND
D/A OUT 0
D/A OUT 1
AGNDReserved
GND
TRIG_IN
SYNC
CTR

Pin description
Analog input 0
Analog input 1
Analog ground
Analog input 2
Analog input 3
Analog ground
Analog input 4
Analog input 5
Analog ground
Analog input 6
Analog input 7
Analog ground
Analog output 0
Analog output 1
Analog groundReserved for future use
GroundTrigger input
Synchronization I/OCounter input

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

27

Signal name
Port A0
Port A1
Port A2
Port A3
Port A4
Port A5Port A6
Port A7GND+VO
GNDPort B0
Port B1
Port B2
Port B3
Port B4
Port B5
Port B6
Port B7
GND

Pin description
Port A bit 0
Port A bit 1
Port A bit 2
Port A bit 3
Port A bit 4
Port A bit 5
Port A bit 6
Port A bit 7
GroundPower output
GroundPort B bit 0
Port B bit 1
Port B bit 2
Port B bit 3
Port B bit 4
Port B bit 5
Port B bit 6
Port B bit 7
Ground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 21, 2016, Norton, Massachusetts USA
EMI6102.12

Measurement Computing Corporation declares under sole responsibility that the productUSB-1208FS-Plusis 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

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Phone: +36 (52) 515400
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