Information furnished by Data Translation, Inc. is believed to be
accurate and reliable; however, no responsibility is assumed by
Data Translation, Inc. for its use; nor for any infringements of
patents or other rights of third parties which may result from its
use. No license is granted by implication or otherwise under any
patent rights of Data Translation, Inc.
Use, duplication, or disclosure by the United States Government
is subject to restrictions as set forth in subparagraph (c)(1)(ii) of
the Rights in Technical Data and Computer software clause at 48
C.F.R, 252.227-7013, or in subparagraph (c)(2) of the Commercial
Computer Software - Registered Rights clause at 48 C.F.R.,
52-227-19 as applicable. Data Translation, Inc., 100 Locke Drive,
Marlboro, MA 01752.
The DT7837 software is based of the Linux open-source
development environment which uses the GNU (General Public
License). Data Translation example programs may use code from
other vendors. This code is for demonstration purposes only. If
you want to use this code for commercial purposes, you must
ensure that you resolve any licensing issues with the appropriate
parties.
Data Translation® is a registered trademark of Data Translation,
Inc.
All other brand and product names are trademarks or registered
trademarks of their respective companies.
Page 3
Radio and Television Interference
This equipment has been tested and found to comply with CISPR EN55022 Class A and
EN61000-6-1 requirements and also with the limits for a Class A digital device, pursuant to
Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against
harmful interference when the equipment is operated in a commercial environment. This
equipment generates, uses, and can radiate radio frequency energy and, if not installed and
used in accordance with the instruction manual, may cause harmful interference to radio
communications. Operation of this equipment in a residential area is likely to cause harmful
interference, in which case the user will be required to correct the interference at his own
expense.
Changes or modifications to this equipment not expressly approved by Data Translation could
void your authority to operate the equipment under Part 15 of the FCC Rules.
Note: This product was verified to meet FCC requirements under test conditions that
included use of shielded cables and connectors between system components. It is important
that you use shielded cables and connectors to reduce the possibility of causing interference
to radio, television, and other electronic devices.
FCC
Page
Canadian Department of Communications Statement
This digital apparatus does not exceed the Class A limits for radio noise emissions from
digital apparatus set out in the Radio Interference Regulations of the Canadian Department of
Communications.
Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les limites
applicables aux appareils numériques de la class A prescrites dans le Règlement sur le
brouillage radioélectrique édicté par le Ministère des Communications du Canada.
The first part of this manual describes how to install and set up your DT7837 module and
verify that your module is working properly.
The second part of this manual describes the features of the DT7837 module and how to
program the DT7837 module using Linux system calls. Troubleshooting information is also
provided.
Intended Audience
This document is intended for engineers, scientists, technicians, or others responsible for
using and/or programming a DT7837 module for data acquisition operations in the Linux
operating system. It is assumed that you have some familiarity with data acquisition
principles and that you understand your application.
How this Manual is Organized
This manual is organized as follows:
• Chapter 1, “Overview,” describes the major features of the DT7837 module, as well as the
supported software and accessories for the module.
About this Manual
• Chapter 2, “Principles of Operation,” describes all of the features of the DT7837 module.
• Chapter 3, “Troubleshooting,” provides information that you can use to resolve problems
with the DT7837 module should they occur.
• Chapter 4, “Calibration,” describes how to calibrate the analog circuitry of the DT7837
module.
• Appendix A, “Specifications,” lists the specifications of the DT7837 module.
• Appendix B, “Connector Pin Assignments and LED Status Indicators,” lists the pin
assignments of the connectors on the DT7837 module, and describes the LED status
indicators on the DT7837 module.
• An index completes this manual.
Conventions Used in this Manual
The following conventions are used in this manual:
• Notes provide useful information or information that requires special emphasis, cautions
provide information to help you avoid losing data or damaging your equipment, and
warnings provide information to help you avoid catastrophic damage to yourself or your
equipment.
• Items that you select or type are shown in bold.
9
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About this Manual
Related Information
Where To Get Help
Refer to the following documents, which can be found on the DT7837 web page on our
website (http://www.datatranslation.com/products/dataacquisition/embedded/DT7837/)
for more information on using the DT7837 module:
• DT7837 Getting Started help file
• DT7837 File I/O Programming Manual
Refer to your Linux documentation for more information about Linux and Texas Instruments
documentation for more information on the TI Sitara AM3352, 1 GHz, ARM® Cortex-A8
processor.
Should you run into problems installing or using a DT7837 module, the Data Translation
Technical Support Department is available to provide technical assistance. Refer to Chapter 4
for more information. If you are outside the United States or Canada, call your local
distributor, whose number is listed on our web site (www.datatranslation.com).
The DT7837 module is an open-source Linux computing platform with a high-accuracy,
dynamic signal analyzer front-end, making it ideal for embedded applications that require
noise, vibration, and acoustic measurements.
The module is composed of two boards (the bottom board contains the ARM block and the
top board contains the I/O block) that connect together, as show in Figure 1. Users can embed
the module into their own enclosure and/or system, as needed.
12
Figure 1: DT7837 Module
The key features of the DT7837 module are as follows:
• Open-source computing platform featuring a TI Sitara AM3352, 1 GHz, ARM® Cortex-A8
processor.
• Linux distribution consisting of a Linux kernel, bootloader, and file system with a DT7837
device driver, USB device (client) driver, and USB host driver.
• Ethernet 10/100 Mbps connectivity to a host computer.
• USB 2.0 full-speed connectivity to a host computer.
Page 13
• USB 2.0 host connection to external devices, such as a mouse, keyboard, or external
storage devices.
• Analog input subsystem:
− Four, single-ended analog input channels available through SMA connectors.
− Four simultaneous sampling, Delta-Sigma, 24-bit analog-to-digital converters (ADCs).
− Support for IEPE (Integrated Electronic Piezoelectric) inputs, including use of a 4 mA
current source with 20 V compliance voltage for AC or DC coupling.
− Programmable throughput rate from 195.3125 Samples/s to 105.469 kSamples/s.
− Input range of ±10 V with software-selectable gains of 1 and 10 for an effective input
range of ±10 V and ±1 V.
− Continuous acquisition from multiple analog input channels simultaneously.
− Supports the ability to return the value of the tachometer, general-purpose
counter/timer, measure counter, and/or digital input port in the analog input data
stream, allowing you to measure a variety of signals synchronously with analog input
measurements.
− Software-programmable trigger source (software trigger, external trigger, or threshold
trigger using any analog input channel) to start acquisition.
Overview
− Accounts for analog input group delay in hardware and allows user-specified trigger
delay to account for analog output group delay.
• Up to eight, TTL digital input lines using the eight general-purpose inputs. You can read
the digital input port directly or you can return the value of the digital input port in the
input data stream.
• Up to eight, TTL digital output lines using the eight general-purpose outputs. You can
write a value to the digital output port directly.
• One, 32-bit, general-purpose counter/timer for performing event counting, rate
generation, and non-repeatable one-shot operations. You can use two general-purpose
input signals for the C/T clock and gate inputs and one general-purpose output signal for
the C/T clock output. You can read the value of the counter/timer directly or through the
input data stream.
• One tachometer input signal. The value of the tachometer input signal can be returned in
the input stream.
• One phase/measure counter. You can program the edge that starts the measurement and
the edge that stops the measurement. Many edge types are supported. The data from the
measure counter can be returned in the input stream.
• 2 GB embedded NAND flash memory that contains the Linux kernel, bootloader, and file
system; this memory can also be used to store user files and data
• 512 MB SDRAM (DDR3) memory
• 8 kBytes EEPROM
• Micro SD connector supports micro SD cards, which can be used as a boot source for
general-purpose file and data storage
• 3.3 V UART, I2C, and an SPI (Serial Peripheral Interface) interfaces for embedded
connectivity.
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Chapter 1
• Serial debug port.
• External power connectors (4-pin DIN or 3-pin Phoenix header) for connecting a +5 VDC
power supply.
14
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Board Layout Overview
The DT7837 module consists of an ARM block and a I/O block. Figure 2 shows the layout of
the ARM block (the bottom board). Figure 3 shows the layout of the I/O block (the top board).
Overview
15
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Chapter 1
Digital Connector
(Tachometer, Digital I/O, External Trigger, Counter/Timer)
Power L ED
Ethernet
Connector
USB Host
Port
USB Device
(Client) Port
SD Card
+5 V Power
AM3552
Processor
Reset/Boot
Switch
Connector to the
I/O Block
Serial
Port 1
(J14)
Serial
Port 0
(J13)
SPI
Port
(J12)
Grounding
Stud
16
Figure 2: Layout of the ARM Block of the DT7837 Module
Page 17
Overview
Output Trigger
LED (bottom)
Input Trigger LED
(top)
Analog Output Connector
(analog output currently not
supported in software)
Analog Input Connectors
Figure 3: Layout of the I/O Block of the DT7837 Module
17
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Chapter 1
Supported Software
The following software is available for use with the DT7837 module:
• DT7837 File I/O Commands – A set of commands in Linux user space for opening a
subsystem or stream, configuring a subsystem or stream, acquiring data in the input
stream, reading or updating the digital I/O port, and/or writing values to the calibration
potentiometers. Numerous example programs are provided to illustrate how to use these
commands. Refer to the DT7837 File I/O Programming Manual for more information.
• DT7837 Kernel Device Driver – The device driver resides in the Linux kernel and is
responsible for performing the functions defined by the DT7837 file I/O commands on the
DT7837 module.
• DT7837 Calibration Utility – This utility, described in Chapter 4, allows you to calibrate
the analog circuitry of the DT7837 module.
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Supported Accessories
The following optional accessories are available for a DT7837 module:
• STP26 screw terminal panel – This screw terminal panel accepts tachometer, digital
input, C/T gate input, and C/T clock input signals from the Digital connector on the
DT7837 module and provides digital output and C/T clock output signals from the
Digital connector on the module.
The 26-pin, 36-inch, EP406 cable is included with the STP26 screw terminal panel. The
cable allows you to attach the STP26 screw terminal panel to the Digital connector on a
DT7837 module.
Figure 4 shows the STP26 and EP406 cable.
Overview
Figure 4: STP26 Screw Terminal Panel and EP406 Cable
• EP405 USB to Serial TTL Debug Cable – This 3Mbaud, 1.8 m cable, shown in Figure 5,
connects the USB port of the host computer to serial UART connector J13 on the DT7837,
allowing you to debug the DT7837 using a terminal interface.
Figure 5: EP405 USB to Serial TTL Debug Cable
19
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Chapter 1
• EP361 External Power Supply – This +5 VDC optional power supply and cable, shown in
Figure 6, connects to the DIN power connector on the DT7837 module and to the wall
power outlet.
Figure 6: EP361 +5 VDC External Power Supply
20
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Getting Started Procedure
Refer to the DT7837 Getting Started help file on our web site
(http://www.datatranslation.com/products/dataacquisition/embedded/DT7837/) for
getting started information
The DT7837 is an open-source Linux computing platform with a high-accuracy, dynamic
signal analyzer front-end.
The DT7837 consists of two boards. The bottom board is the ARM block, which includes the
ARM processor, PC and embedded connectivity options, and memory, as well as the digital
I/O, counter/timer, measure counter, and tachometer circuitry.
The top board is the I/O block, which includes four 24-bit IEPE analog inputs and one 24-bit
stimulus analog output.
Note: The analog output circuitry is currently not supported in software.
Figure 7 shows a block diagram of the DT7837 module.
24
Figure 7: Block Diagram of the DT7837 Module
Page 25
ARM Block
The ARM block of the DT7837 module uses the TI Sitara AM3352 processor and its associated
peripherals to provide an open-source, single-board computer. The AM3352 supports many
different interfaces, many of which are shared on the configurable I/O pins. In addition to the
AM3352, the DT7837 module uses an embedded NAND flash and an FPGA.
This section describes the features of the ARM block in more detail.
ARM Processor
The AM3352 is based on the ARM Cortex-8 32-bit processor and is configured to run at
600 MHz.
Refer to the following web site for more information on this processor:
http://www.ti.com/product/am3352
Memory
Principles of Operation
A 512 MB, DDR3, SDRAM memory device is connected to the AM3352 processor through a
dedicated DDR (Double Data Rate) memory interface.
Embedded NAND Flash
A 2 GB embedded NAND flash device is connected to the AM3352 processor through the
16-bit GPMC (General Purpose Memory Controller) bus, and can be accessed at the CS0
address space. The flash memory contains the Linux kernel, bootloader, and the file system.
You can also use the flash memory for general-purpose data and file storage as well as for
input data and waveform storage.
EEPROM
An 8 kByte EEPROM device is connected to the I2C0, 2-wire, serial interface of the AM3352
processor. The EEPROM stores information about the device, including the calibration
information.
25
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Chapter 2
Micro SD Card
A micro SD card slot is provided to support optional high-speed (up to 24 MB/s) micro SD
cards. Micro SD cards (not provided with the module) communicate with the AM3352
processor using the MMC0 port in the 4-bit interface mode.
You can use a micro SD card as a boot source or for general-purpose file and data storage.
USB Device (Client) Port
The DT7837 module provides a USB 2.0 device (client) port on a type B receptacle. The device
port connects to the USB port 0 controller of the AM3352 processor.
When connected to a host computer through this USB port, the host computer can identify the
DT7837 module and load the appropriate drivers through the enumeration process.
USB Host Port
The DT7837 provides a high-speed USB 2.0 host port on a type A receptacle. The host port
connects to the USB port 1 controller of the AM3352 processor. The USB host port supports
any USB device, provided that the required software is installed on the Linux operating
system.
If desired, you can connect USB devices, such as a keyboard, mouse, memory stick, or hub to
this port.
Serial Port 0
Serial port 0 is a 3.3 V TTL serial interface provided on a 6-pin header. This port supports
transmit and receive signals (no handshaking), and connects to the UART 0 interface of the
AM3552 processor.
This port is particularly useful when you are debugging your applications. To use this port,
use the EP405 USB to serial TTL adapter cable.
Serial Port 1 / I2C2 Port
Serial port 1 and the I2C2 port are provided on the same 6-pin header.
Serial port 1 is a 3.3 V TTL serial interface that supports transmit and receive signals, and
connects to the UART1 interface of the AM3552 processor.
The bidirectional I
provided for embedded connectivity. It is possible to reconfigure the pins of the I
interface as the remaining UART 1 pins to provide the full functionality of serial port 1.
2
C2 port connects to the I2C port 2 interface of the AM3552 processor and is
2
C port 2
26
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SPI Port
The SPI (Serial Peripheral Interface) is provided on an additional 6-pin header for embedded
connectivity. This port connects to the SPI port 1 interface of the AM3552 processor.
GPMC Bus Interface
A 16-bit address/data multiplexed bus interface is supplied by the processor. In addition to
the NAND flash, this bus also supports the FPGA. All control registers for the DT7837 are
accessible in the CS1 address space. The CS3 address space provides access to the input FIFO.
Additional Signals Used on Processor
The following are additional pins on the processor that are connected for use on the DT7837
module:
• XDMAEvent0 – Configured, but not used
• XDMAEvent1 – Used for an analog output DMA event (currently not supported)
• XDMAEvent2 – Used for an analog input DMA event
Principles of Operation
• GPIO1_20 – Configured for a DMA event, but not used
• GPIO1_25 – Configured as an interrupt, but not used
• GPIO1_26 – Configured as an interrupt, but not used
• GPIO1_27 – Configured as an interrupt, but not used
• GPIO3_20 – Configured as an interrupt, but not used
Digital Connector
The Digital connector provides access to the tachometer input and GPIO (General Purpose
Input and Output) signals of the DT7837 module. Refer to page 77 for the pin assignments of
this connector.
Using software, you can specify a general-purpose input signal as the signal source for the
following destinations:
• Digital input (the default signal for each general-purpose input pin)
• External A/D trigger input
• External D/A trigger input
• Gate input for the general-purpose counter/timer (C/T 0)
• Clock input for the general-purpose counter/timer (C/T 0)
27
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Chapter 2
Using software, you can specify a general-purpose (general-purpose) output signal as the
signal source for one of these destinations:
• Digital output (the default signal for each general-purpose output pin)
• Clock output for the general-purpose counter/timer (C/T 0)
Note that a single general-purpose input may drive several destinations at the same time.
However, a single general-purpose output can have only one driving source.
28
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Analog Input Features
This section describes the following features of analog input (A/D) subsystem on the DT7837
module:
• Analog input channels, described on this page
• Input ranges and gains, described on this page
• IEPE functions, described on page 30
• Input resolution, described on page 30
• Continuous sampling mode, described on page 30
• Input triggers, described on page 31
• Input sample clock source and sampling frequency, described on page 32
• Data format and transfer, described on page 33
• Error conditions, described on page 33
Analog Input Channels
Principles of Operation
The DT7837 module provides four analog input channels (channels 0 to 3). These are
single-ended channels; you can connect IEPE sensors to these inputs, if desired; refer to page
30 for more information on IEPE functions.
Note: To maintain simultaneous operation, all analog input connections on the DT7837
module must have the same lead lengths.
The DT7837 module uses four, Delta-Sigma, 24-bit ADCs that provide anti-aliasing filters
based on the clock rate. These filters remove aliasing, which is a condition where high
frequency input components erroneously appear as lower frequencies after sampling.
Using software, you can specify which analog input channels to sample by specifying bits 0 to
3 in the channel mask for the input stream.
Input Ranges and Gains
The DT7837 module provides an input range of ±10 V and software-selectable gains of 1 and
10. This provides effective input ranges of ±10 V (when the gain is 1) and ±1 V (when the gain
is 10).
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Chapter 2
IEPE Functions
Applications that require accelerometer, vibration, noise, or sonar measurements often use
IEPE sensors. IEPE conditioning is built-in to the analog input circuitry of the DT7837 module.
The modules support the following software-programmable IEPE functions for each analog
input channel:
• Excitation current source – The DT7837 module provides an internal excitation current
source of 4 mA. You can turn the internal excitation current source on or off using
software.
• Coupling type – You can select whether AC coupling or DC coupling is used.
DT7837 modules provide +20 V compliance voltage.
Note: If you enable the use of the internal excitation current source, it is recommended that
you choose AC coupling.
Input Resolution
The resolution of the analog input channels is fixed at 24 bits; you cannot specify the
resolution in software.
Continuous Sampling Mode
The DT7837 module supports continuous sampling mode on the input stream. This is an
asynchronous I/O operation that is non-blocking so that your application can perform other
operations while acquisition is being performed.
In continuous sampling mode, you can acquire data from the following channels in the input
data stream: analog input channels 0 to 3, the tachometer input, the general-purpose
counter/timer, the measure counter, and the digital input port. In software, you specify the
channel mask for the input stream to determine which channels to sample. The bits of the
channel mask are as follows:
• Channels (bits) 0 to 3 – Analog input channels 0 to 3
• Channel (bit) 4 – Tachometer; refer to page 34 for more information
• Channel (bit) 5 – Counter/timer 0; refer to page 36 for more information
• Channel (bit) 6 – Measure counter; refer to page 43 for more information
• Channel (bit) 7 – Digital input port; refer to page 47 for more information
30
The trigger that starts acquisition for the channels in the input stream can be any of the
supported start trigger sources. Refer to page 31 for more information about the start trigger
sources. However, the input stream of the module must be armed (using software) before the
module can detect the trigger condition.
Page 31
Principles of Operation
Chan 0
Chan 1
Chan 7
Input
Sample
Clock
Chan 0
Chan 1
Chan 7
Chan 0
Chan 1
Chan 7
Chan 0
Chan 1
Chan 7
Start Trigger occurs
Pre-trigger data acquired
Chan 0
Chan 1
Chan 7
Chan 0
Chan 1
Chan 7
If a software trigger is specified as the start trigger, acquisition starts immediately when the
software start command is executed. Otherwise, acquisition begins when the specified trigger
signal is detected. When it detects the specified start trigger, the module simultaneously
acquires data from all of the channels in specified in the input stream. Acquisition repeats
continuously until you stop the operation. The conversion rate is determined by the sampling
frequency; refer to page 32 for more information.
When you stop the operation using software, the DMA engine stops and no further data is
collected. It is the programmer’s responsibility to clean up all inprocess control block
resources. To restart the operation, the input stream of the module must be armed and started
again.
Figure 8 illustrates continuous acquisition mode using three channels: analog input channels 0
and 1 and the digital input port. When the start trigger is detected, samples from the specified
channels are acquired continuously.
Input Triggers
Figure 8: Continuous Sampling Mode on the DT7837 Module
A trigger is an event that occurs based on a specified set of conditions. For continuous
sampling mode of the channels in the input data stream, described on page 30, you must
specify a start trigger to start acquisition.
The DT7837 module supports the following sources for the start trigger; you configure the
trigger source and its parameters using software:
• Software trigger – A software trigger event occurs when you start the analog input
operation (the computer issues a write to the module to begin conversions). Using
software, specify the start trigger source as a software trigger.
• External digital (TTL) trigger – An external digital (TTL) trigger event occurs when the
module detects a rising- or falling-edge transition on the signal connected to a
general-purpose input pin on the Digital connector. (Refer to page 27 for more the pin
descriptions of the Digital connector.) You can specify which edge is active using software.
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Chapter 2
• Threshold trigger – The start trigger event occurs when the signal attached to a specified
analog input channel rises above or falls below a user-specified threshold value. Using
software, you specify the following parameters:
− Edge – Specify a rising-edge threshold trigger if you want to trigger when the signal
rises above a threshold level, or a falling-edge threshold trigger if you want to trigger
when the signal falls below a threshold level.
− Threshold channel – Specify any one of the analog input channels as the threshold
input channel.
− Threshold level – Specify a value between ±10 V for a gain of 1 or ±1 V for a gain of 10
as the threshold level. Note that in software, this value must be entered as counts.
To convert raw counts to volts, use the following formulas:
Gain of 1
Gain of 10
Note: The DT7837 driver sets the threshold level as close as possible to the value that you
specify. However, the value that you specify may not be the actual value that is set. You
can return the actual threshold level that was set using software.
The DT7837 module supports an internal A/D clock, which is derived from the 48 MHz
reference clock. The reference clock is generated from the onboard oscillator.
Using software, you specify the frequency at which to pace input operations. The sampling
frequency can range from 195.3125 Hz to 105.469 kHz.
Note: According to sampling theory (Nyquist Theorem), specify a frequency that is at least
twice as fast as the input’s highest frequency component. For example, to accurately sample a
20 kHz signal, specify a sampling frequency of at least 40 kHz to avoid aliasing.
32
The DT7837 driver sets the sampling frequency as close as possible to the value that you
specify. However, the value that you specify may not be the actual value that is set. You can
return the actual sampling frequency that was set using software.
Once the sample clock is started, the module requires 39 conversions before the first A/D
sample is valid. The valid sample is aligned with the start trigger.
Page 33
Note: After changing the A/D master clock, wait a few milliseconds for the master clock to
settle before calibrating the module or performing an acquisition.
The DT7837 module has two power modes: low power mode and high power mode. Low
power mode is used when you specify a sampling frequency less than 52.734 kHz. High
power mode is used when you specify a sampling frequency greater than or equal to
52.734 kHz. If you change the power mode from low to high power or from high power to
low power, and then configure the device, the module is self-calibrated. You may notice that
it takes time after the device is configured to complete the calibration process.
Data Format and Transfer
The DT7837 has an input FIFO of 2 kSamples (8 kBytes). Each sample of the DT7837 is a 32-bit
value.
The DT7837 module uses offset binary data encoding, where 000000 represents negative
full-scale, and FFFFFFh represents positive full-scale. Use software to specify the data
encoding as binary. The ADC outputs FFFFFFh for above-range signals, and 000000 for
below-range signals.
Principles of Operation
Error Conditions
The DT7837 module will detect an overrun error if the user buffers are not being sent to the
module fast enough, and the A/D converters run out of user buffers to fill. To avoid this error,
try one or more of the following:
• Reduce the clock rate of the A/D
• Increase the size of the buffers
• Increase the number of buffers
• Close any other applications that are running
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Chapter 2
Tachometer Input Features
You can connect a tachometer signal with a range of ±30 V to pin 23 of the Digital connector.
(Refer to page 27 for the pin descriptions of the Digital connector.) The tachometer input
accepts signals with a maximum frequency of 1 MHz and a minimum pulse width of 0.4 μs.
The threshold voltage is fixed at +2 V with 0.5 V of hysteresis.
To read the value of tachometer in the input stream, specify bit 4 in the channel mask for the
input stream.
You can measure the frequency or period of the tachometer input signal to calculate the
rotation speed for high-level (±30 V) tachometer input signals. An internal 12 MHz counter is
used for the measurement, yielding a resolution of 83 ns (1/12 MHz).
You can read the number of counts between two consecutive starting edges of the tachometer
input signal by including channel 4 for the DT7837 in the analog input channel list. The
starting edge is programmable (either rising or falling).
Using software, you can also specify a flag (called Stale) that indicates whether or not the data
is new. If the Stale flag is set as Used (the default value), the most significant bit (MSB) of the
value is set to 0 to indicate new data; reading the value before the measurement is complete
returns an MSB of 1. If the Stale flag is set to Not Used, the MSB is always set to 0.
When the input operation is started, the internal 12 MHz counter starts incrementing when it
detects the first starting edge of the tachometer input and stops incrementing when it detects
the next starting edge; at that point, the counter stores the count. The stored count is
maintained until it is read as part of the input data stream or until a new count is stored. The
next tachometer measurement operation is started automatically.
If the sample rate of the input subsystem is faster than the tachometer input frequency, then
the stored count retains the current value when the count is read by the input subsystem. The
operation of the Stale flag in this case is described as follows:
• If another input subsystem sample occurs before another measure completes and the Stale
flag is enabled, then the Stale flag is set and the stale measure count is written into the
input data stream.
• If another input subsystem sample occurs before another measure completes and the Stale
flag is disabled, then the Stale flag is not set and the stale measure count is written into the
input data stream.
If the input sample rate is slower than the tachometer input frequency, then as each period
measurement completes, a new count value is stored. When the input subsystem sample
occurs, the most recently stored measure count is written into the input data stream.
A data pipeline is used in the hardware to compensate for the A/D group delay and
synchronizes the value of the tachometer input with the analog input measurements so that
all measurements are correlated in time. The tachometer input is treated like any other
channel in the analog input channel list; therefore, all the triggering and conversion modes
supported for analog input channels are supported for the tachometer input.
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Principles of Operation
When you read the value of the tachometer input as part of the analog input data stream, you
might see results similar to the following:
Table 1: An Example of Reading the Tachometer Input as Part of the Analog Input Data Stream
Tachomete r
TimeA/D Value
1050020Operation started, but is not complete
205004 0Operation not complete
3050030Operation not complete
40500212373Operation complete
50500012373Next operation started, but is not complete
60500212373Operation not complete
70500412373Operation not complete
80500314503Operation complete
90500214503Next operation started, but is not complete
Input Value
Status of Operation
Using the count that is returned from the tachometer input, you can determine the following:
• Frequency of a signal pulse (the number of periods per second). You can calculate the
frequency as follows:
− Frequency = 12 MHz/(Number of counts – 1)
where 12 MHz is the internal counter/timer clock frequency
For example, if the count is 21, the measured frequency is 600 kHz (12 MHz/20).
• Period of a signal pulse. You can calculate the period as follows:
− Period = 1/Frequency
− Period = (Number of counts – 1)/12 MHz
where 12 MHz is the internal counter/timer clock frequency
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Chapter 2
Clock Input SIgnal
(internal or external)
Counter
Gate Input Signal
(software or external
input)
Pulse Output Signal
General-Purpose Counter/Timer Features
This section describes the following features of counter/timer (C/T) operations:
• C/T channels, described below
• C/T clock sources, described on page 37
• Gate types, described on page 37
• Pulse output period and duty cycle, described on page 38
• C/T operation modes, described on page 39
C/T Channels
DT7837 modules provide one 32-bit, general-purpose counter/timer (C/T 0). As shown in
Figure 9, the counter/timer accepts a clock input and gate input signal and outputs a pulse
(clock output signal).
Figure 9: Counter/Timer Channel
Using software, you define general-purpose I/O pins on the Digital connector for the external
C/T clock input, external C/T gate input, and C/T clock output signals.
To read the value of C/T 0 in the input stream, specify bit 5 in the channel mask of the input
stream.
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C/T Clock Input Sources
The following clock input sources are available for the general-purpose counter/timer; you
select the clock source through software:
• Internal C/T clock – The internal C/T clock uses a 48 MHz time base. This clock source is
typically used for one-shot, repetitive one-shot, and rate generation operations.
• External C/T clock – An external C/T clock is useful when you want to pace
counter/timer operations at rates not available with the internal C/T clock or if you want
to pace at uneven intervals. The frequency of the external C/T clock can range from
0.0112 Hz to 10 MHz.
This clock source is typically used for event counting and rate generation operations.
Using software, specify one of the general-purpose input pins (1 to 8) of the Digital
connector on the DT7837 module as the external C/T clock input. Then, physically
connect the external clock signal to the selected pin. (Refer to page 27 for the pin
descriptions of the Digital connector.) Counter/timer operations start on the rising edge of
the clock input signal.
Note: If you specify a counter/timer in the input stream, the A/D clock determines how
often you want to read the counter value. Refer to page 32 for more information about the
A/D sample clock.
Principles of Operation
Gate Types
The edge or level of the counter gate signal determines when a counter/timer operation is
enabled.
Unless you are using a software gate (no gate), define one of the general-purpose input pins of
the Digital connector on the DT7837 module as the external C/T gate input using software.
Then, physically connect the external gate signal to the selected pin. (Refer to page 27 for the
pin descriptions of the Digital connector.)
DT7837 modules provide the following gate types; you select the gate type using software:
• None – A software start command enables any counter/timer operation immediately
after execution. (No general-purpose input signal is required if a gate type of None is
selected.)
• Low external gate input – Specifies a logic low or falling edge gate type. For event
counting and rate generation mode, the operation is enabled when the counter’s gate
signal is low and is disabled when the counter’s gate signal is high. For one-shot mode or
repetitive one-shot mode, the operation is enabled when the counter’s gate signal goes
from a high to a low transition and is disabled when the counter ’s gate signal goes from a
low to a high transition.
You specify one of the general-purpose input pins (1 to 8) of the Digital connector on the
DT7837 module as the external C/T gate input. Ensure that you physically connect the
external gate signal to the selected pin. (Refer to page 27 for the pin descriptions of the
Digital connector.)
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Chapter 2
Total Pulse Period = 10
With an external C/T input clock of
10000 Hz and a period of 10, the
output signal is 1000 Hz.
Active Pulse Width = 2 for 20% duty cycle
low pulse
high pulse
• High external gate input – Specifies a logic high or rising edge gate type. For event
counting and rate generation mode, the operation is enabled when the counter’s gate
signal is high and is disabled when the counter’s gate signal is low. For one-shot mode or
repetitive one-shot mode, the operation is enabled when the counter’s gate signal goes
from a low to a high transition and is disabled when the counter ’s gate signal goes from a
high to a low transition.
You specify one of the general-purpose input pins (1 to 8) of the Digital connector on the
DT7837 module as the external C/T gate input. Ensure that you physically connect the
external gate signal to the selected pin. (Refer to page 27 for the pin descriptions of the
Digital connector.)
Pulse Output Period, Pulse Width, and Polarity
If you want to perform a C/T output operation, define one of the general-purpose output pins
(11 to 18) of the Digital connector on the DT7837 module as the external C/T output signal
using software. Then, connect the external C/T output signal to the selected pin. (Refer to
page 27 for the pin descriptions of the Digital connector.)
For the DT7837 module, you can program the polarity of the output pulse (active high or
active low). For an active high pulse, the high portion of the total pulse output period is the
active portion of the counter/timer pulse output signal. For an active low pulse, the low
portion of the total pulse output period is the active portion of the counter/timer pulse output
signal.
Using software, you can specify the number of input clock cycles that are used to create one
period of the counter clock output signal. You can also specify the number of input clock
cycles used to create the active pulse width (or duty cycle) of the C/T output signal.
For example, if you are using an external C/T clock running at 10000 Hz as the input clock
source of the counter/timer, and you want to generate a output signal of 1000 Hz with a 20%
duty cycle, specify a period of 10 (10000 Hz divided by 10 is 1000 Hz) and a pulse width of 2
(the period of 10 multiplied by 20%). This is illustrated in Figure 10.
Figure 10: Example of a Pulse Output
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Note: If you are using an internal C/T clock input source, you can output pulses using a
maximum frequency of 24 MHz. Note, however, that the integrity of the signal degrades at
frequencies greater than 10 MHz.
If you are using an external C/T clock input source, you can output pulses using a maximum
frequency of 5 MHz.
Counter/Timer Operation Modes
The general-purpose counter/timer on the DT7837 module supports the following
counter/timer operation modes:
• Event counting
• Rate generation
• Non-repeatable one-shot
•Idle
Principles of Operation
The following subsections describe these modes in more detail.
Event Counting
Use event counting mode if you want to count the number of rising edges that occur on the
counter’s clock input when the counter’s gate signal is active (low-level or high-level).
You can count a maximum of 4,294,967,296 events before the counter rolls over to 0 and starts
counting again.
Using software, you must specify the following parameters for the event counting operation:
• Active gate type (external low level or external high level). Refer to page 37 for more
information about the supported gate types.
• The general-purpose input pin to use for the external gate signal. Ensure that you
physically connect the gate signal to this input pin. Refer to page 27 for the pin
descriptions of the Digital connector.
• The C/T clock source (internal or external). Note that in event counting mode, the
external C/T clock is more useful than an internal C/T clock; refer to page 37 for more
information about the C/T clock sources.
• The general-purpose input pin to use for the external C/T clock input. Ensure that you
physically connect the clock input signal to this input pin. Refer to page 27 for the pin
descriptions of the Digital connector.
Refer to page 39 for an example of connecting an event counting application.
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Chapter 2
Rate Generation
Use rate generation mode to generate a continuous pulse output signal from the counter ’s
output signal. You can use this pulse output signal as an external clock to pace other
operations, such as an analog input or other counter/timer operations.
The pulse output operation is enabled whenever the counter’s gate signal is at the specified
level. While the pulse output operation is enabled, the counter outputs a pulse of the specified
type and frequency continuously. As soon as the operation is disabled, rate generation stops.
You can output pulses using a maximum frequency of 24 MHz (if using the internal C/T
clock) or 5 MHz (if using the external C/T clock).
Note: The integrity of the signal degrades at frequencies greater than 10 MHz.
Using software, you must specify the following parameters for the rate generation operation:
• Active gate type (external low level or external high level). Refer to page 37 for more
information about the supported gate types.
• The general-purpose input pin to use for the external gate signal. Ensure that you
physically connect the gate signal to this input pin. Refer to page 27 for the pin
descriptions of the Digital connector.
• The C/T clock source (internal or external). Refer to page 37 for more information about
the C/T clock sources.
• If you are using an external C/T clock source, the general-purpose input pin to use for the
external C/T clock input. Ensure that you physically connect the clock input signal to this
input pin. Refer to page 27 for the pin descriptions of the Digital connector.
• The period of the output pulse. Refer to page 38 for more information about the period of
the output pulse.
• The pulse width (duty cycle) of the active pulse. Refer to page 38 for more information
about the pulse width of the output pulse.
• The general-purpose output signal to use for the C/T clock output signal. Ensure that you
physically connect the C/T output signal to this output pin. Refer to page 27 for the pin
descriptions of the Digital connector.
• The polarity of the output signal (active high or active low). Refer to page 38 for more
information on the polarity of the output pulse.
Refer to page 40 for an example of connecting a rate generation application.
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Principles of Operation
Gate Input (High)
Output Pulses*
Gate Signal is Ignored
*You can determine period, pulse width, and polarity of the output pulse using software.
Non-Repeatable One-Shot
Use non-repeatable one-shot mode to generate a single output pulse from the counter
whenever the specified edge is detected on the counter’s gate signal (after the pulse period
from the previous output pulse expires). Any gate signals that occur while the pulse is being
output are not detected by the module, as shown in Figure 11. The module continues to output
a pulse when the specified gate edge is detected until you stop the operation. You can use this
mode to clean up a poor clock input signal by changing its pulse width, and then outputting
it.
Figure 11: Non-Repeatable One-Shot Mode
Using software, you must specify the following parameters for the non-repeatable one-shot
operation:
• Active gate type that enables the operation. Refer to page 37 for more information about
the supported gate types.
• The general-purpose input pin to use for the external gate signal. Ensure that you
physically connect the gate signal to this input pin. Refer to page 27 for the pin
descriptions of the Digital connector.
• The C/T clock source (internal or external) that generates the pulse. Note that in one-shot
mode, the internal C/T clock is more useful than an external C/T clock; refer to page 37
for more information about the C/T clock sources.
• The general-purpose input pin to use for the external C/T clock input. Ensure that you
physically connect the clock input signal to this input pin. Refer to page 27 for the pin
descriptions of the Digital connector.
• The period of the output pulse. Refer to page 38 for more information about the period of
the output pulse.
• The pulse width (duty cycle) of the active pulse. Refer to page 38 for more information
about the pulse width of the output pulse.
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Chapter 2
• The general-purpose output signal to use for the C/T clock output signal. Ensure that you
physically connect the C/T output signal to this output pin. Refer to page 27 for the pin
descriptions of the Digital connector.
• The polarity of the output signal (active high or active low). Refer to page 38 for more
information on the polarity of the output pulse.
• Retriggerable setting of 0 for non-repeatable one-shot.
Refer to page 41 for an example of connecting a non-repeatable one-shot application.
Idle Mode
If you use idle mode, the counter no longer drives the clock output signal that is assigned to
one of the general-purpose output signals (pins 11 to 18) of the Digital connector.
Note: The value of the counter output signal can also be overwritten by writing to the
digital output subsystem.
If you assigned a general-purpose input signal as a counter clock or gate input (or external
trigger), you can read the value of the signal as you would any other digital input signal.|
Refer to page 47 for more information on digital I/O operations.
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Measure Counter Features
DT7837 modules provides one measure counter. Using this counter, you can measure the
frequency, period, or pulse width of a single signal or the time period between two signals and
return the value in the analog input stream. This is useful for correlating the analog input data
with digital positional data, measuring the frequency of a signal, or as a tachometer. An
internal 48 MHz counter is used for the measurement, yielding a resolution of 20 ns
(1/48 MHz).
Using software commands, you can configure the following parameters for the measure
counter:
• The signals that start and stop the measurement. Refer to Tab l e 2 for the supported start
and stop signals.
Table 2: Possible Start and Stop Signals
SignalConnection Required
A/D conversion complete No connection required.
Principles of Operation
Tachometer input
(falling edge or rising edge)
Digital input 0
(falling edge or rising edge)
Digital input 1
(falling edge or rising edge)
Digital input 2
(falling edge or rising edge)
Digital input 3
(falling edge or rising edge)
Digital input 4
(falling edge or rising edge)
Digital input 5
(falling edge or rising edge)
Digital input 6
(falling edge or rising edge)
Connect to Tachometer input.
Connect a digital input, external A/D trigger, C/T clock input, or
C/T gate input to general-purpose input 0 (pin 1) of the Digital
connector. By default, this is digital input 0.
Connect a digital input, external A/D trigger, C/T clock input, or
C/T gate input to general-purpose input 1 (pin 2) of the Digital
connector. By default, this is digital input 1.
Connect a digital input, external A/D trigger, C/T clock input, or
C/T gate input to general-purpose input 2 (pin 3) of the Digital
connector. By default, this is digital input 2.
Connect a digital input, external A/D trigger, C/T clock input, or
C/T gate input to general-purpose input 3 (pin 4) of the Digital
connector. By default, this is digital input 3.
Connect a digital input, external A/D trigger, C/T clock input, or
C/T gate input to general-purpose input 4 (pin 5) of the Digital
connector. By default, this is digital input 4.
Connect a digital input, external A/D trigger, C/T clock input, or
C/T gate input to general-purpose input 5 (pin 6) of the Digital
connector. By default, this is digital input 5.
Connect a digital input, external A/D trigger, C/T clock input, or
C/T gate input to general-purpose input 6 (pin 7) of the Digital
connector. By default, this is digital input 6.
Digital input 7
(falling edge or rising edge)
Connect a digital input, external A/D trigger, C/T clock input, or
C/T gate input to general-purpose input 7 (pin 8) of the Digital
connector. By default, this is digital input 7.
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Chapter 2
• A flag (called Stale) indicating whether or not the data is new. This flag is used only when
the start edge and the stop edge is set to use the same pin and edge.
If the Stale flag is set as Used (the default value), the most significant bit (MSB) of the
value is set to 0 to indicate new data; reading the value before the measurement is
complete returns an MSB of 1. If the Stale flag is set to Not Used, the MSB is always set to
0.
When the selected start edge is the same as the selected stop edge, the internal 48 MHz
counter starts incrementing when it detects the first start edge of the selected input signal and
stops incrementing when it detects the selected stop edge (which is the same as the start edge,
in this case); at that point, the counter stores and resets the count. The stored count is
maintained until it is read as part of the input data stream or until a new count is stored. Since
the stop edge is the same as the start edge in this case, the stop edge for the current
measurement is the start edge for the next measurement; therefore, no waveform periods are
missed. The value of the measure count depends on the input subsystem sample frequency,
described as follows:
• If the input subsystem sample frequency is faster than the selected input frequency, then
the stored measure count retains the current value when it is read by the input subsystem.
The operation of the Stale flag in this case is described as follows:
− If another input subsystem sample occurs before another measure completes and the
Stale flag is used, then the Stale flag is set and the stale measure count is written into
the input data stream.
− If another input subsystem sample occurs before another measure completes and the
Stale flag is not used, then the Stale flag is not set and the stale measure count is
written into the input data stream.
• If the input subsystem sample frequency is slower than the selected input frequency, then
the new measure count value is stored as each period measurement completes. When an
input subsystem sample occurs, then the most recently stored measure count is written
into the input data stream.
When the selected start edge is not the same as the selected stop edge, the internal 48 MHz
counter starts incrementing when it detects the selected start edge and stops incrementing
when it detects the next selected stop edge; at that point, the counter stores and resets the
count. The stored count is maintained until it is read as part of the input data stream or until a
new count is stored. The value of the measure count depends on the input subsystem sample
frequency, described as follows:
• If the input subsystem sample rate is faster than the selected measurement period, then
the stored count retains the current value when the count is read by the input subsystem.
The operation of the Stale flag in this case is described as follows:
− If another input subsystem sample occurs before another measure completes and the
Stale flag is used, then the Stale flag is set and the stale measure count is written into
the input data stream.
44
− If another input subsystem sample occurs before another measure completes and the
Stale flag is not used, then the Stale flag is not set and the stale measure count is
written into the input data stream.
Page 45
Principles of Operation
• If the input subsystem sample rate is slower than the selected measurement period, then a
new count value is stored as each period measurement completes. When an input
subsystem sample occurs, the most recently stored measure count is written into the input
data stream.
A data pipeline is used in the hardware to compensate for the A/D group delay and
synchronizes the value of the measure counter with the analog input measurements, so that all
measurements are correlated in time. The measure counter is treated like any other channel in
the analog input channel list; therefore, all the triggering and conversion modes supported for
analog input channels are supported for the measure counter.
When you read the value of the measure counter as part of the analog input data stream, you
might see results similar to the following:
Table 3: An Example of Reading a Measure Counter as Part of the Analog Input Data Stream
Measure Counter
TimeA/D Value
1050020Operation started, but is not complete
Val ues
Status of Operation
205004 0Operation not complete
3050030Operation not complete
40500212373Operation complete
50500012373Next operation started, but is not complete
60500212373Operation not complete
70500412373Operation not complete
80500314503Operation complete
90500214503Next operation started, but is not complete
Using the count that is returned from the measure counter, you can determine the following:
• Frequency between the start and stop signals/edges. You can calculate the frequency as
follows:
− Frequency = 48 MHz/(Number of counts – 1)
where 48 MHz is the internal measure counter frequency
For example, if the count is 201, the measured frequency is 240 kHz (48 MHz/200).
• Period between the start and stop signals/edges. You can calculate the period as follows:
− Period = 1/Frequency
− Period = (Number of counts – 1)/48 MHz
where 48 MHz is the internal measure counter frequency
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Chapter 2
• Pulse width of the start and stop signal/edges (rising to falling edge or falling edge to
rising edge). You can calculate the period as follows:
− Pulse width = 1/Frequency
− Pulse width = (Number of counts – 1)/48 MHz
where 48 MHz is the internal measure counter frequency
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Digital I/O Features
This section describes the following features of digital I/O operations:
• Digital I/O lines
•Operation modes
Digital I/O Lines
DT7837 modules support one digital input port, consisting of up to 8 digital input lines (lines
0 to 7) and one digital output port, consisting of up to 8 digital output lines (lines 0 to 7). The
resolution is fixed at 8 bits.
By default, general-purpose input pins 1 to 8 of the Digital connector on the DT7837 module
correspond to digital input signals 0 to 7. Similarly, general-purpose output pins 11 to 18 of the
Digital connector on the DT7837 module correspond to digital output signals 0 to 7.
Note: If you assigned a general-purpose input signal as a counter clock or gate input or as
an external trigger, you can read the value of the signal as you would any other digital input
signal, if desired.
Principles of Operation
If you want to write a value to a specific digital output line, ensure that the corresponding pin
of the Digital connector is not configured for another use (such as the output of the
counter/timer) or you could corrupt the signal on the pin.
A digital line is high if its value is 1; a digital line is low if its value is 0. On power up or reset,
a low value (0) is output from each of the digital output lines and a high value (1) is read from
each of the digital input lines if the lines are not connected.
Operation Modes
DT7837 modules support the following digital I/O operation modes:
• Synchronous read and write operations – Using software, you can read the value of the
digital input port using a synchronous read operation or write a value to the digital
output port using a synchronous write operation. The operation is blocking, in that it does
not return until the value is read or written.
You do not specify a trigger or clock for a synchronous read or write operation. The
operation stops automatically once the value is read or written.
• Continuous digital input – Using software, enter the digital input port (all 8 digital input
lines) as specify bit 7 of the channel mask in the input stream. You can specify the
sampling frequency and trigger source for the input stream. The trigger starts the
acquisition. The input sample clock paces the acquisition of data from the digital input
port as well as the analog input channels, tachometer input, general-purpose
counter/timer, and/or the measure counter.
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Chapter 2
DT7837
#1
DT7837
#2
DT7837
#n
.
.
.
Device Under
Test
External
Tri gger
Inputs
Inputs
Inputs
Triggering Acquisition on Multiple Modules
The internal clock on the DT7837 module is derived from the 48 MHz crystal oscillator and
provides the timing for the analog input subsystem on the module.
You can start acquisition on multiple modules by connecting all modules to a shared external
trigger input, as shown in Figure 12. Using software, you must define one of the
general-purpose input pins on the Digital connector on each DT7837 module as the external
trigger signal. When triggered, the modules start acquiring data at the same time.
Using this connection scheme, the measurements of one module are not synchronous with the
measurements of another module as they do not share the same reference clock.
48
Figure 12: Triggering Multiple Modules Using an External Trigger Source
Should you experience problems using the DT7837 module, follow these steps:
1. Read all the appropriate sections of this manual and the DT7837 File I/O Programming
Manual.
2. Refer to the supplied example programs for clarification.
3. Check that you have installed your hardware devices properly.
4. Check that you have installed the software properly.
If you are still having difficulty using the DT7837 module, Data Translation’s Technical
Support Department is available to provide technical assistance.
To request technical support, go to our web site at http://www.datatranslation.com and click
on the Support link.
When requesting technical support, be prepared to provide the following information:
• Your product serial number
• The hardware/software product you need help on
If you are located outside the USA, contact your local distributor; see our web site
(www.datatranslation.com) for the name and telephone number of your nearest distributor.
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If Your Module Needs Factory Service
If your module must be returned to Data Translation, do the following:
1. Record the module’s serial number, and then contact the Customer Service Department at
(508) 481-3700, ext. 1323 (if you are in the USA) and obtain a Return Material
Authorization (RMA).
If you are located outside the USA, call your local distributor for authorization and
shipping instructions; see our web site (www.datatranslation.com) for the name and
telephone number of your nearest distributor. All return shipments to Data Translation
must be marked with the correct RMA number to ensure proper processing.
2. Using the original packing materials, if available, package the module as follows:
− Wrap the module in an electrically conductive plastic material. Handle with ground
protection. A static discharge can destroy components on the module.
− Place in a secure shipping container.
3. Return the module to the following address, making sure the RMA number is visible on
the outside of the box.
Customer Service Dept.
Data Translation, Inc.
100 Locke Drive
Marlboro, MA 01752-1192
DT7837 modules are calibrated at the factory and should not require calibration for initial use.
We recommend that you check and, if necessary, readjust the calibration of the analog circuitry
every six months using the DT7837 Calibration Utility.
The DT7837 Calibration Utility is provided as both a web application (cal-server) and a
command-line program (dt7837cal).
This chapter describes how to calibrate the analog input subsystem of a DT7837 module using
the command-line program, dt7837cal.
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Using the Calibration Utility
To use the command-line DT7837 Calibration Utility, perform the following steps:
1. From the usr/local/dt7837/dt7837-calibration directory on the module, type dt7837cal,
and press Enter.
The main screen of the DT7837 Calibration Utility appears.
Calibration
2. Once the calibration utility is running, calibrate the analog input circuitry either
automatically or manually, as described on page 56.
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Chapter 4
Calibrating the Analog Input Subsystem
This section describes how to use the DT7837 Calibration Utility to calibrate each analog input
channel of the DT7837 module.
Warming up the Module
Before calibrating the analog input circuitry, ensure that the module has been powered on for
at least one hour.
Connecting a Precision Voltage Source
To calibrate the analog input circuitry, you need to connect an external precision voltage
source to the DT7837 module that is capable of generating 0.0000 V to +9.3750 V. Connect the
precision voltage source to the first analog input channel that you want to calibrate (typically
analog input channel 0).
Using the Auto-Calibration Procedure
Auto-calibration is the easiest to use and is the recommended calibration method. To
auto-calibrate the analog input subsystem, do the following:
1. From the main menu of the program, select 2: Automatically calibrate an analog input
channel.
2. Enter the number (0 to 3) of the analog input channel that you want to calibrate, then
enter Y to continue.
3. Verify that 0.0000 V is applied to the channel that you want to calibrate.
4. Adjust the value to 0.0000 V by typing a value between 0 and 255 or by pressing the + or –
key.
5. Verify that +9.3750 V is applied to the channel that you want to calibrate.
6. Adjust the value to +9.3750 V by typing a value between 0 and 255 or by pressing the + or
– key.
7. Verify that +0.9375 V is applied to the channel that you want to calibrate.
8. Adjust the value to +0.9375 V by typing a value between 0 and 255 or by pressing the + or
– key.
9. Repeat steps 2 through 8 for the remaining analog input channels on the module.
10. When you have finished calibrating the module, press X from the main menu to exit from
the program.
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Using the Manual Calibration Procedure
The DT7837 has two gains (1 and 10) and two power modes: low power mode and high power
mode. Low power mode is calibrated when you specify a sampling frequency less than
52.734 kHz. High power mode is calibrated when you specify a sampling frequency greater
than 52.734 kHz. Ensure that you calibrate each analog input channel for gains of 1 and 10 if
you are using both gains and for both high and low power mode if you are using sampling
frequencies below and above 52.734 kHz. By default, this utility uses DC coupling with the
current source disabled.
To manually calibrate the analog input circuitry, do the following for each channel:
1. From the main menu of the program, select 1: Manually calibrate an analog input
channel.
2. Enter the number (0 to 3) of the analog input channel that you want to calibrate.
3. Enter the gain value (1 or 10) to calibrate for the analog input channel.
4. Enter 0 to calibrate the offset potentiometer or 1 to calibrate the gain potentiometer.
5. Enter 0 to calibrate the selected potentiometer for sampling frequencies less than or equal
to 52734 Hz or 1 to calibrate the selected potentiometer for sampling frequencies greater
than 52734 Hz.
The current calibrations selections are displayed.
Calibration
6. If the current selections are correct, enter Y. To fix an entry, enter N to repeat these steps.
7. If you chose to calibrate the offset potentiometer in step 4, adjust the potentiometer as
follows:
a. Verify that 0.0000 V is applied to the channel that you want to calibrate.
b. Adjust the value to 0.0000 V by typing a value between 0 and 255 or by pressing the +
or – key.
c.Press Enter to display the current information for the channel, including the value of
the potentiometer and the current reading.
d. Repeat steps 7b and 7c until the reading is calibrated to 0.0000 V.
e. Once calibrated, press x to exit to the main menu.
8. If you chose to calibrate the gain potentiometer in step 4 and selected a gain of 1 in step 3,
adjust the potentiometer as follows:
a. Verify that +9.375 V is applied to the channel that you want to calibrate.
b. Adjust the value to +9.375 V by typing a value between 0 and 255 or by pressing the +
or – key.
c.Press Enter to display the current information for the channel, including the value of
the potentiometer and the current reading.
d.
Repeat steps 8b and 8c until the reading is calibrated to +9.375 V.
e. Press x to exit to the main menu.
57
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Chapter 4
9. If you chose to calibrate the gain potentiometer in step 4 and selected a gain of 10 in step 3,
adjust the potentiometer as follows:
a. Verify that +0.9375 V is applied to the channel that you want to calibrate.
b. Adjust the value to +0.9375 V by typing a value between 0 and 255 or by pressing the
+ or – key.
c.Press Enter to display the current information for the channel, including the value of
the potentiometer and the current reading.
d. Repeat steps 9b and 9c until the reading is calibrated to +0.9375 V.
e. Press x to exit to the main menu.
10. Repeat these steps for each gain and sampling frequency for the selected channel.
11. Repeat these steps for each analog input channel.
12. When you have finished calibrating the module, press X from the main menu to exit from
the program.
Restoring Factory-Calibration Settings
If you wish, you can restore the analog input calibration values for each channel to their
original factory settings by selecting 3: Restore all analog input factory calibration settings
from the main menu of the DT7837 Calibration Utility.
A prompt is displayed to inform that the values were reset.
Low pass cutoff, –3 dB:
High pass cutoff, –3 dB (AC coupling):
Channel-to-channel crosstalk
Input Signal = 1 kHz:
Input impedance1 M
CouplingAC/DC (software-selectable per channel)
IEPE current source4 mA ±0.5%
IEPE compliance voltage24 V
a
a
b
100 kHz to 27 MHz
512 x sample frequency
256 x sample frequency
0.49 x sample frequency, Hz
0.453 x sample frequency, Hz
0.547 x sample frequency, Hz
400 kHz
0.1 Hz
≤ –121 dB with 50 Ω termination
Ω || 20 pF
c
60
IEPE current source noise
DC to 1 kHz5 nARMS
Page 61
DC Accuracy
Offset error
d
Specifications
Table 4: Analog Input Subsystem Specifications (cont.)
FeatureDT7837 Specifications
±1 mV
Offset error temperature coefficient±(7.2
μV/° C )/ Gain) ± 100 μV/° C
Gain error
Gain of 1:
Gain of 10:
±0.02%
±0.5%
Gain error temperature coefficient50 ppm/° C
ADC Integral Non-Linearity error, INL±0.0006% of full-scale range
ADC Differential Non-Linearity error, DNLMonotonic to 24 bits
Dynamic Performance
Effective Number of Bits, ENOB
e
f
Gain of 1Gain of 10
(1 kHz input, 105.5 kSPS)
–1 dBFS input:
–6 dBFS input:
Signal to Noise and Distortion Ratio, SINAD
15 bits
16 bits
g
(1 kHz input, 105.5 kSPS)
–1 dBFS input:
–6 dBFS input:
Signal to Noise Ratio, SNR
h
93 dB
92 dB
(1 kHz input, 105.5 kSPS)
–1 dBFS input:
–6 dBFS input:
Total Harmonic Distortion, THD
i
97 dB
96 dB
(1 kHz input, 105.5 kSPS)
–1 dBFS input:
–6 dBFS input:
Spurious Free Dynamic Range, SFDR
j
–102 dB
–100 dB
(1 kHz input, 105.5 kSPS)
–1 dBFS input:
–6 dBFS input:
97 dBFS
103 dBFS
15 bits
16 bits
93 dB
92 dB
97 dB
96 dB
–102 dB
–101 dB
98 dBFS
102 dBFS
Noise Floor
Ω input termination, 105.5 kSPS)56 μVRMS65 μVRMS
(50
Overvoltage Protection
Overvoltage protection
Power on:
Power off:
+40 V to –20 V
±40 V
ESD protection
Arc:
Contact:
a. The total frequency response is the combined frequency response of the ADC Delta Sigma filter and the analog filter.
b. Channel 0 is the reference channel with a 20 Vpp signal and a maximum sample rate of 105.469 kSamples/s.
c. Cable capacitance of 30 pF per foot (typical) must be added.
d. Offset errors are referred to the input.
e. ENOB, SINAD, SNR, THD, and SFDR measurements were made with a 16384 point FFT with a minimum 4-term
Blackman Harris window.
f. Effective Number of Bits (ENOB) is calculated from the SINAD value with adjustment for level below full-scale of the
input signal.
where, IBFS is a positive value in dB, representing the ratio of a full-scale signal to the input signal.
g. Signal to Noise and Distortion (SINAD) is the ratio of the RMS value of the input signal to the RMS sum of all other
spectral components, excluding DC.
h. Signal to Noise Ratio (SNR) is the ratio of the RMS value of the input signal to the RMS sum of all other spectral
components, excluding harmonics and DC.
i. Total Harmonic Distortion (THD) is the ratio of the RMS value of the input signal to the RMS sum of all harmonics.
j. Spurious Free Dynamic Range (SFDR) is the ratio of the RMS full-scale range to the RMS value of the largest peak
spurious component, including harmonics.
62
Page 63
Digital Input Specifications
Tabl e 5 lists the specifications for the digital input signals available on the Digital connector of
the DT7837 module.
Table 5: Digital Input Specifications
FeatureSpecifications
Number of general-purpose inputs8
Input type3.3 V high-speed CMOS, Schmitt trigger, 5 V tolerant
Specifications
Input termination22.1 k
+ Voltage threshold2.0 V typical
– Voltage threshold0.8 V typical
Clocked with sample clock:Yes, if the digital input port is included in the input data stream
Ω pull-up resistor to 3.3 V
(channel/bit 7)
63
Page 64
Appendix A
Digital Output Specifications
Tabl e 5 lists the specifications for the digital output signals available on the Digital connector
of the DT7837 module.
Table 6: Digital Output Specifications
FeatureSpecifications
Number of general-purpose outputs8
Output typeLVTTL
Logic high output voltage2.4 V minimum
Logic low output voltage0.4 V maximum
Logic high output current–10 mA maximum
Logic low output current4 mA maximum
Short circuit current50 mA maximum
Clocked with sample clockCurrently not supported
64
Page 65
Tachometer Input Specifications
Tabl e 7 lists the specifications for the tachometer input available on the Digital connector of
the DT7837 module.
Table 7: Tachometer Input Specifications
FeatureSpecifications
Number of channels1
Resolution31 bits per channel
Input voltage range±30 V
Threshold voltage+2 V with 0.5 V hysteresis
Input terminationNone
Maximum input frequency1 MHz
Specifications
a
Minimum pulse width high/low (minimum amount of
time it takes a C/T to recognize an input pulse)
Clock frequency for tachometer measurements12 MHz (83 ns resolution)
Overvoltage protection ±30 V
Clocked with sample clock:Yes, if the tachometer is included in the input
a. Limited by signal integrity and input signal conditioning.
0.4 μs
data stream (channel/bit 4)
65
Page 66
Appendix A
Measure Counter Specifications
Tabl e 8 lists the specifications for the measure counter on the DT7837 module.
Table 8: Measure Counter Specifications
FeatureSpecifications
Number of measure counters1
Resolution31 bits per channel
Clock frequency for measurement counters48 MHz (20.8 ns resolution)
Maximum input frequency10 MHz
Minimum pulse width high/low50 ns (0.4 μs if the tachometer input is used for the
starting edge and stopping edge)
Start and stop signals/edgesA/D conversion complete
Tachometer input (falling or rising edge)
Digital inputs 0 to 7 (falling or rising edge)
C/T 0 Clock input (falling or rising edge)
C/T 0 Gate input (falling or rising edge)
a
Clocked with sample clock:Yes, if the measure counter is included in the input data
stream (channel/bit 6)
a. Limited by signal integrity and input signal conditioning.
66
Page 67
General-Purpose Counter/Timer Specifications
Tabl e 7 lists the specifications for the general-purpose counter/timer (C/T 0) on the DT7837
Figure 13 shows the layout of the analog input SMA connectors (connectors J1-J5) on the I/O
block (top board) of the DT7837 module.
Figure 13: Analog Input Connectors
76
Page 77
Digital Connector
251
262
Figure 14 shows the layout of the 26-pin Digital connector (J8) on the ARM block (bottom
board) of the DT7837 module. This connector brings out the tachometer, GPIO, and event
output signals for the module.
Figure 14: Layout of the Digital Connector
Tabl e 17 lists the pin assignments for the Digital connector on the DT7837 module.
Connector Pin Assignments and LED Status Indicators
Table 17: Pin Assignments for the Digital Connector
Connector
Pin Number
1General Purpose Input 0
2General Purpose Input 1
3General Purpose Input 2
4General Purpose Input 3
5General Purpose Input 4
6General Purpose Input 5
7General Purpose Input 6
8General Purpose Input 7
Signal Description
a
a
a
a
a
a
a
a
9Digital Ground22Digital Ground
10Digital Ground23Tachometer input
11General Purpose Output 0
12General Purpose Output 1
13General Purpose Output 2
b
b
b
Connector
Pin Number
14General Purpose Output 3
15General Purpose Output 4
16General Purpose Output 5
17General Purpose Output 6
18General Purpose Output 7
19Digital Ground
20Digital Ground
21Event Out (currently not
supported)
24Digital Ground
25+5 V
26Digital Ground
Signal Description
b
b
b
b
b
a. The input signals are +5 V tolerant and 22 kΩ pull-ups are provided. By default, they are configured as digital
input signals. By default, these signals are configured as digital input signals.
b. The output signals are driven by LVTTL buffers and are capable of providing up to ±24 mA of drive current at
standard LVTTL levels. By default, they are configured as digital output signals. By default, these signals are
configured as digital output signals.
77
Page 78
Appendix B
Using software, you can specify a general-purpose input signal as the signal source for the
following destinations:
• Digital input (the default signal for each general-purpose input pin)
• External A/D trigger input
• Gate input for the general-purpose counter/timer (C/T 0)
• Clock input for the general-purpose counter/timer (C/T 0)
Using software, you can specify a general-purpose output signal as the signal source for one
of these destinations:
• Digital output (the default signal for each general-purpose output pin)
• Clock output for the general-purpose counter/timer (C/T 0)
Note that a single general-purpose input may drive several destinations at the same time.
However, a single general-purpose output can have only one driving source.
78
Page 79
USB Device (Client) Connector
1
23
4
Figure 15 shows the layout of the USB device (client) connector (J4) on the ARM block (bottom
board) of the DT7837 module. This is a type B connector.
Figure 15: Layout of the USB Type B Connector for the USB Device (Client) Port
Connector Pin Assignments and LED Status Indicators
Tabl e 18 lists the pin assignments for the USB type B connector on the DT7837 module for the
USB device (client) port.
Table 18: Pin Assignments for the USB Type B Connector for the USB Device (Client) Port
Connector
Pin Number
1USB +5 V3USB Data +
2USB Data –4USB Ground
Signal Description
Connector
Pin Number
Signal Description
Note: The outer shell provides cable shield to chassis ground.
79
Page 80
Appendix B
1
2
3
4
USB Host Connector
Figure 15 shows the layout of the USB host connector (J2) on the ARM block (bottom board) of
the DT7837 module. This is a type A connector.
Figure 16: Layout of the USB Type A Connector for the USB Host Port
Tabl e 19 lists the pin assignments for the USB type A connector on the DT7837 module for the
USB host port.
Table 19: Pin Assignments for the USB Type B Connector for the USB Device (Client) Port
Connector
Pin Number
1USB +5 V3USB Data +
2USB Data –4USB Ground
Signal Description
Connector
Pin Number
Signal Description
Note: The outer shell provides cable shield to chassis ground.
80
Page 81
Ethernet Connector
12345678
LED1LED2
Figure 15 shows the layout of the Ethernet (RJ45) connector (J1) on the ARM block (bottom
board) of the DT7837 module.
Figure 17: Layout of the Ethernet Connector
Connector Pin Assignments and LED Status Indicators
Tabl e 20 lists the pin assignments for the Ethernet connector on the DT7837 module.
Table 20: Pin Assignments for the Ethernet Connector
Connector
Pin Number
1Transmit+5Not connected
2Transmit–6Receive–
3Receive+7Not connected
4Not connected8Not connected
LED1Activity (green)LED2Link (yellow)
Note: The outer shell provides cable shield to chassis ground.
Signal Description
Connector
Pin Number
Signal Description
81
Page 82
Appendix B
Bot t o m Vie w
Card Detect Switch
87654321
9
10
11
1213
14
15
Micro SD Card Connector
Figure 18 shows the layout of the Micro SD Card connector (J5) on the ARM block (bottom
board) of the DT7837 module.
Tabl e 21 lists the pin assignments for the Micro SD card connector on the DT7837 module.
Table 21: Pin Assignments for the Micro SD Card Connector
Connector
Pin Number
1DAT29CD
2DAT3/CD10DGND
3CMD11CGND
4+3.3 V12CGND
5CLK13CGND
6DGND14CGND
7DAT015CGND
8DAT1
Figure 18: Micro SD Card Connector
Connector
Signal Description
Pin Number
Signal Description
82
Page 83
External +5 V Power Connector
21
34
The DT7837 module provides two connectors for attaching a +5 VDC external power supply:
a DIN connector and a 3-position Phoenix header.
Figure 19 shows the layout of the DIN power connector (J6) on the ARM block (bottom board)
of the DT7837.
Figure 19: Layout of the DIN Power Connector
Connector Pin Assignments and LED Status Indicators
Tabl e 22 lists the pin assignments for the external DIN power connector on the DT7837
module.
Table 22: Pin Assignments for the External Power Connector
Connector
Pin Number
1+5 VDC 2+5 VDC
3Ground4Ground
Signal Description
Connector
Pin Number
Signal Description
You can connect the optional EP361 power supply to the DIN connector, if desired. Refer to
page 72 and page 73 for detailed specifications of this power supply.
83
Page 84
Appendix B
Terminal 1
Terminal 2
Terminal 3
Figure 20 shows the layout of the 3-pin Phoenix header (TB1) on the ARM block (bottom
board) of the DT7837 module.
Figure 20: Layout of the 3-Position Phoenix Header
Tabl e 23 lists the terminal assignments for the 3-position header on the DT7837 module.
Table 23: Terminal Assignments for the 3-Position Header (TB1) on the DT7837 Module
Terminal Number Signal Description
1+5 VDC
2Digital Ground
3Chassis Ground
Note that you must connect an external power supply to this header that meets the
specifications described on page 74.
84
Page 85
Serial Connectors
Serial
Port 1/
I
2
C2 Port
Serial
Port 0
SPI
Port
61
*Note that the pin order of connector
J13 is reversed from connectors J12
and J14.
Figure 15 shows the layout of the 6-pin serial connectors (J12, J13, and J14) on the ARM block
(bottom board) of the DT7837 module.
Connector Pin Assignments and LED Status Indicators
Figure 21: Layout of the Serial Connectors
These connectors are described in the sections that follow.
Serial Port 0 (UART 0)
Figure 15 shows the layout of the Serial port 0 (J13) on the ARM block (bottom board) of the
DT7837 module.
Figure 22: Layout of Serial Port 0 (J13)
85
Page 86
Appendix B
16
Tabl e 24 lists the pin assignments for serial port 0 on the DT7837 module.
Table 24: Pin Assignments for Serial Port 0 (J13) on the DT7837 Module
SPI Connector
Figure 15 shows the layout of the SPI connector (J12) on the ARM block (bottom board) of the
DT7837 module.
Connector
Pin Number
1DGND
2Not Connected
3Not Connected
4UART0_RX
5UART0_TX
6Not Connected
Signal Description
Figure 23: Layout of SPI Connector (J12)
Tabl e 25 lists the pin assignments for the SPI connector on the DT7837 module.
Table 25: Pin Assignments for SPI Connector (J12) on the DT7837 Module
Pin NumberSignal Description
1SPI1_D0
2SPI1_SCLK
3SPI1_CS0
4SPI1_D1
5DGND
6+3.3 V
86
Page 87
Serial Port 1 / I2C2 Connector
16
Figure 15 shows the layout of the Serial port 1/ I2C2 connector (J14) on the ARM block
(bottom board) of the DT7837 module.
Figure 24: Layout of Serial Port 1 / I
Connector Pin Assignments and LED Status Indicators
2
C Port (J14)
Tabl e 26 lists the pin assignments for the Serial port 1/ I
Table 26: Pin Assignments for Serial Port 1 / I
Pin NumberSignal Description
1UART1_RX
2UART1_TX
3I
4I
5DGND
6+3.3 V
2
C2_SDA
2
C2_SCL
2
C connector on the DT7837 module.
2
C Connector (J14) on the DT7837 Module
87
Page 88
Appendix B
11
13
15
17
19
1
3
5
7
9
31
33
35
37
39
21
23
25
27
29
51
53
55
57
59
41
43
45
47
49
71
73
75
77
79
61
63
65
67
69
91
93
95
97
99
81
83
85
87
89
111
113
115
117
119
101
103
105
107
109
12
14
16
18
20
2
4
6
8
10
32
34
36
38
40
22
24
26
28
30
52
54
56
58
60
42
44
46
48
50
72
74
76
78
80
62
64
66
68
70
92
94
96
98
100
82
84
86
88
90
112
114
116
118
120
102
104
106
108
110
I/O Block Connector
Figure 15 shows the layout of the I/O block connector (J9) on the DT7837 module.
88
Figure 25: I/O Block Connector (J9)
Page 89
Connector Pin Assignments and LED Status Indicators
Tabl e 27 lists the pin assignments of the I/O block connector on the DT7837 module (on both
the ARM block and the I/O block).
Table 27: Pin Assignments for the I/O Block Connector (J9)
Connector
Pin Number
1+5 V2+5 V
3+5 V4+5 V
5Ground6Ground
7Ground8Ground
9Test 010Test 1
11Test 212Test 3
13LED 014LED 1
15LED 216LED 3
17LED 418LED 5
19LED 620LED 7
21DC/DC Sync 022DC/DC Sync 1
23Ground24Ground
25I
27I
Signal Description
2
C SLC 026I2C SLC 1
2
C SDA 028I2C SDA 1
Connector
Pin Number
Signal Description
29Ground30Ground
31Write Enable 032Write Enable 1
33Read Enable 034Read Enable 1
35In Sync Control 036In Sync Control 1
37In Sync Control 238In Sync Control 3
39Ground40Ground
41DAQ Clock 042DAQ Clock 1
43DAQ Clock 244DAQ Clock 3
45Ground46Ground
47Sync 048Sync 1
49Data Clock 050Data Clock 1
51Data Clock 252Data Clock 3
53Ground54Ground
55In Serial Data 056In Serial Data 1
57In Serial Data 258In Serial Data 3
89
Page 90
Appendix B
Table 27: Pin Assignments for the I/O Block Connector (J9)
Connector
Pin Number
59In Serial Data 450In Serial Data 5
61In Serial Data 662In Serial Data 7
63Ground64Ground
65In Parallel Data 066In Parallel Data 1
67In Parallel Data 268In Parallel Data 3
69In Parallel Data 470In Parallel Data 5
71In Parallel Data 672In Parallel Data 7
73Ground74Ground
75Control 076Control 1
77Control 278Control 3
79Control 480Control 5
81Control 682Control 7
83Ground84Ground
85Control 886Control 9
Signal Description
Connector
Pin Number
Signal Description
87Control 1088Control 11
89Control 1290Control 13
91Control 1492Control 15
93Ground94Ground
95Out Parallel Data 096Out Parallel Data 1
97Out Parallel Data 298Out Parallel Data 3
99Out Parallel Data 4100Out Parallel Data 5
101Out Parallel Data 6102Out Parallel Data 7
103Ground104Ground
105Out Serial Data 0106Out Serial Data 1
107Out Serial Data 2108Out Serial Data 3
109Out Serial Data 4110Out Serial Data 5
111Out Serial Data 6112Out Serial Data 7
113Ground114Ground
115Out Sync Control 0116Out Sync Control 1
117Out Sync Control 2118Out Sync Control 3
90
119Ground120Ground
Page 91
STP26 Screw Terminal Panel
The STP26 contains one 26-pin connector and a screw terminal block (TB1). The 26-pin
connector provides access to the signals from the Digital connector on the DT7837 module.
Figure 26 shows the layout of the STP26 screw terminal panel.
Connector Pin Assignments and LED Status Indicators
Figure 26: Layout of the STP26 Screw Terminal Panel
Tabl e 28 lists the screw terminal assignments for the STP26 screw terminal panel.
91
Page 92
Appendix B
Table 28: Screw Terminal Assignments for the STP26 Screw Terminal Panel
Screw TerminalSignal Description
XShield
26Digital Ground
25+5 V
24Digital Ground
23Tachometer Input
22Digital Ground
21Reserved for future use
20Digital Ground
19Digital Ground
18General-Purpose Output 7
17General-Purpose Output 6
16General-Purpose Output 5
15General-Purpose Output 4
14General-Purpose Output 3
13General-Purpose Output 2
12General-Purpose Output 1
11General-Purpose Output 0
10Digital Ground
9Digital Ground
8General-Purpose Input 7
7General-Purpose Input 6
6General-Purpose Input 5
5General-Purpose Input 4
4General-Purpose Input 3
3General-Purpose Input 2
2General-Purpose Input 1
1General-Purpose Input 0
92
Page 93
LED Status Indicators
Power L ED
Input Trigger LED
Output Trigger LED
The DT7837 module has a Power LED indicator on the ARM block (bottom board) and trigger
LEDs on the I/O block (top board), as shown in Figure 27.
Connector Pin Assignments and LED Status Indicators
Figure 27: Power LED on the DT7837 Module
These LEDs are described in Tab l e 29 .
Table 29: LED Status Indicators on the DT7837 Module
LEDColor of the LEDStatus Description
Input Trigger
LED
Output
Trigger LED
Power LEDOffPower off.
OffIdle.
Solid amberInput subsystem armed; it is waiting for an external digital
trigger or threshold trigger (the module must have been
configured for one of these trigger types).
Solid greenInput subsystem has been triggered.
OffIdle.
Solid amberOutput subsystem armed; it is waiting for an external digital
trigger or threshold trigger (the module must have been
configured for one of these trigger types).
Solid greenOutput subsystem has been triggered.
Solid greenPower on.
93
Page 94
Appendix B
94
Page 95
Index
Index
Symbols
+5 V power connector 83, 84
Numerics
3-position Phoenix header 84
A
accessories
EP405 USB to serial TTL debug cable
EP406 cable
STP26 screw terminal panel
aliasing
AM3352 processor
analog input
calibrating
channels
connectors
data format and transfer
error conditions
gain
29
IEPE functions
input range
resolution
sample clock
specifications
triggers
ARM block
ARM processor
19
19
32
25
56
29
76
33
33
30
29
30
32
60
31
25
25
C
C/T, see counter/timer 66, 67
calibrating the module
analog input subsystem
running the calibration utility
channels
analog input
counter/timer
digital I/O
digital input
measure counter
tachometer
client port, USB
29
36
47
47
43
34
26
56
55
19
clock sources
analog input
counter/timer
connectors
+5 V power
analog input
digital
Ethernet
I/O block
I2C2
87
micro SD card
serial
85
serial port 0
serial port 1
SPI
86
USB client
USB host
conversion rate
counter/timer
channels
clock sources
gate types
specifications
subsystem specifications
counting events
coupling type
current source
customer service
32
37
83
76
77
81
88
82
8587
79
80
31
36
37
37
67
66
39
30
30
51
D
data encoding 33
data format and transfer, input data
DDR3 memory
digital connector
digital I/O operations
continuous digital input
47
lines
synchronous read
synchronous write
digital trigger
DIN power connector
DT7837 Calibration Utility
duty cycle
25
27, 77
47
47
47
31
83
18
38
33
95
Page 96
Index
E
EEPROM 25
embedded NAND flash
encoding data
environmental specifications
EP405 USB to serial TTL debug cable
EP406 cable
errors, analog input
Ethernet connector
event counting
excitation current source
external clock
external digital trigger
33
19
39
37
25
70
33
81
30
31
F
factory service 51
file I/O commands
flash
25
formatting input data
FPGA
27
frequency
analog input operations
external C/T clock
18
33
32
37
G
gain 29
gate type
generating one-shot pulses
generating pulses
GMPC bus interface
group delay
oscillator, specifications 69
output pulses
Output Trigger LED
40, 41
93
96
H
host port, USB 26
I
I2C2 connector 26, 87
idle mode
IEPE features
input
channels
ranges
resolution
Input Trigger LED
internal C/T clock
internal sample clock
42
30
29
29
30
9337
32
P
physical specifications 70
polarity of counter output signal
ports, digital I/O
power connector
3-pin Phoenix header
DIN
83
Power LED
power specifications
processor
pulse output
non-repeatable one-shot
period
pulse width
rate generation
pulse width
25
38
47
84
93
70, 74
41
38
40
38
38
Page 97
Index
R
ranges, analog input 29
rate generation
regulatory specifications
resolution
analog input
digital I/O
returning boards to the factory
RMA
51
40
71
30
47
51
S
sample clock 32
SD card
SDRAM
serial connectors
serial peripheral interface
serial port 0
serial port 1
serial port 1 connector
signals used on processor
size, module
software trigger
specifications
analog input
connector
counter/timer
counter/timer specifications
environmental
EP361 external power supply
external power for the 3-position header
master oscillator
physical
power
regulatory
tachometer input
triggers
60
72
67
66
70
73
69
70
70
71
65
68
86
27
external digital (TTL) trigger
software
threshold trigger
31
32
31
9119, 91
74
technical support
threshold trigger
transferring input data
triggers
external
software
specifications
threshold
troubleshooting
TTL trigger
type A connector
type B USB connector
31
31
50
32
68
32
50
31
80
U
UART 0 85, 86, 87
UART 1
UART0
UART1
units, counter/timer
USB client port
USB device connector
USB device port
USB host connector
USB host port
872626
36
26
26
80
26
V
voltage ranges 29
W
warm-up time 56
33
79
79
T
tachometer input
features
specifications
34
65
97
Page 98
Index
98
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