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WebDAQ 504 User’s Guide
June 2024

About this User’s Guide
What you will learn from this user’s guideThis user’s guide describes the WebDAQ 504 data acquisition device, the WebDAQ web interface, and lists device
specifications.

Where to find more information
Additional information about the WebDAQ Series of internet enabled data loggers is available on our website at
digilent.com. You can also contact Digilent with specific questions.
•••

WebDAQ web interface: Open the Help window for information about using WebDAQ software.
WiFi adapters approved for use with the WebDAQ Series: USB WiFi Adapters
Tech support: Digilent Forum

For international customers, contact your local distributor. Refer to the International Distributors section on our
website.

Hazardous voltages
Take the following precautions if you connect hazardous voltages to the WebDAQ 504. A hazardous
voltage is a voltage greater than 42.4 Vpk or 60 VDC to earth ground.
•••

Ensure that hazardous voltage wiring is performed only by qualified personnel adhering to local
electrical standards.
Do not mix hazardous voltage circuits and human-accessible circuits on the same device.
Make sure that devices and circuits connected to the WebDAQ are properly insulated from humancontact.

Hazardous locations: The WebDAQ 504 is not certified for use in hazardous locations.

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WebDAQ 504 User’s Guide

Introducing the WebDAQ 504
The WebDAQ 504 is part of the WebDAQ Series of Internet enabled data loggers. WebDAQ 504 is a
vibration/acoustic data acquisition and logging device that provides the following features:
•
•
•
•
•
•
•
•
•
•
•

4 simultaneously sampled analog inputs
24-bit resolution
Data rates up to 51.2 kS/s per channel
AC/DC coupling
IEPE signal conditioning
Anti-aliasing filters Overvoltage protection
Four bidirectional, isolated DIO
10/100 Ethernet interface
Support for USB WiFi adapters for wireless connectivity
Support for USB mass storage devices and SD cards for data logging or file transfer
Powered by an external power supply

WebDAQ Series devices are designed with an integrated operating system and web interface. You communicate
with the device over a network connection using the web interface opened in a web browser.
••••

Mobile support – access the WebDAQ from any device with a web browser, such as a phone or tablet
Remote monitoring and control
Run simple to complex logging operations
Flexible task schedulingPowered by Raspberry Pi®
The WebDAQ 504 is designed with the Raspberry Pi Compute Module, featuring a quad core processor with speeds
up to 1.2 GHz, 1GB RAM and 4 GB Flash memory.

Integrated operating system and web service
The WebDAQ 504 is a complete data acquisition system containing an embedded operating system and web
server. The operating system resides in internal flash memory and includes a web service and device driver. All
configuration, acquisition, and data management are performed using the web interface.

Ethernet interface
The WebDAQ 504 has a built-in 10/100 BASE-T auto-negotiation, high-speed communication port. You can accessand configure your WebDAQ from anywhere with access to the network to which it is connected.
A unique MAC address is assigned to each device at the factory. You configure the Ethernet connection settings
through a web interface. The default network name uses the format webdaq-xxxxxx, where xxxxxx are thelower six digits of the factory-assigned MAC address. You can change this name with the web interface.

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WebDAQ 504 User’s Guide

Open-source software
WebDAQ firmware uses open-source software components, click here to download the WebDAQ REST API. Refer
to Licenses for the licensing information of each component. Open-source code is available upon request from the
Digilent forum.

Saving large data files
If you expect to acquire a large amount of data to a single file when logging to external media, do not use media
formatted with the FAT32 file system. FAT32 is limited to a 4 GB maximum file size. If the log file on FAT32 media
grows beyond that size, a "File too large" error is returned and the acquisition stops. Before starting a logging
session of this type, reformat the media using a different file system such as NTFS.

UnpackingAs with any electronic device, you should take care while handling to avoid damage from static electricity. Before
removing the board 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.

Setting up the WebDAQ
Connecting to a local area network
The WebDAQ requires a TCP/IP connection to a network or the Ethernet port of a computer. A standard Ethernet
cable is shipped with the device. The WebDAQ IP address type is set by default for DHCP/Link-Local. Whenconnected to a network, the device first attempts to receive an IP address from a DHCP server. If this fails, a linklocal address is used. Use of a static address requires configuration via the web interface. The IP address identifies
the WebDAQ on the network and is used to access the web interface.

Connecting to a network with DHCP enabled
Connect one end of the Ethernet cable to the connector on the WebDAQ rear panel and connect the other end toa 10Base-T or 100Base-TX compatible Ethernet port, hub, or switch. Once the device is detected, DHCP assigns anaddress. A different address may be assigned each time the hardware is connected to the network.
WiFi support
After successfully configuring a wired connection, you can use the web interface to configure the WebDAQ for
wireless communication. Refer to the Configuring the WebDAQ for wireless communication section for more
information.

Connecting directly to a PC
Connect one end of the Ethernet cable to the connector on the WebDAQ rear panel and connect the other end
directly to the Ethernet port on a PC. The WebDAQ attempts to communicate with the host PC using
169.254.100.100 – the link-local address stored on the device. The host PC may accept this address or use a
different address. The link-local address is valid only for communications between the WebDAQ and the host PC towhich it is connected.

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WebDAQ 504 User’s Guide

Connecting the external power adapter
Connect the network cable before connecting to external power
Connecting to the external supply before installing on a network results in the device attempting to auto-negotiate
a network address before one is available.
An external power adapter is included with each shipment.
Connect the adapter to the power connector labeled EXT PWR on the device rear panel and plug the AC adapter
into an electrical outlet.
Press the POWER button. The POWER LED on the rear panel turns yellow as the hardware starts up, and green
when it is ready for use.

Detecting the device on a network
WebDAQ uses the "zeroconf" zero-configuration protocol to announce its presence on a local area network.
Zeroconf uses a device name which can be accessed from other computers on the network.
Zero-configuration networking is helpful to find your WebDAQ hardware on the network
The easiest way to add zeroconf support to Windows is to install Bonjour Print Services. Bonjour software is Apple's
implementation of zero-configuration networking and is readily available as a free download – open a browser
window and search for Bonjour Print Services. Zeroconf is built into popular applications such as Apple iTunes® andinstant messaging software, so your computer may already support it. Many Linux systems will have the Avahi
version of zeroconf installed by default, so it's likely zeroconf is available if you're running Linux.

Accessing the WebDAQ web interface
To access the WebDAQ web interface, open a browser window and enter http://webdaq-xxxxxx.local, where
xxxxxx is the last 6 digits of the MAC address. The MAC address is on a label at the bottom of the WebDAQ
enclosure.
••If your network is configured for the zeroconf protocol, the WebDAQ web interface opens.
If the web interface does not open or an error is returned, install a device discovery tool such as Bonjour
Print Services. Refer to the note above about zero-configuration networking.

Browser support
The latest version of Chrome, Firefox, Safari, UC Browser, or Opera recommended. Compatible with the Edgebrowser version 79 and up. Not recommended for use with earlier versions of the Edge browser. Not
recommended for use with Internet Explorer.

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WebDAQ 504 User’s Guide
The WebDAQ web interface is shown below.

Figure 1. WebDAQ web interface.

Use the WebDAQ web interface to configure hardware and acquisition options, schedule and run jobs, and to view
and manage data. The Help window provides details about all components on the web interface. Once a
connection is established and you can communicate with the device, you can change the configuration for othernetwork scenarios.

Configuring the WebDAQ for wireless communication
Once communication is established on a wired network, you can connect a WiFi adapter to the USB port and use
the web interface to configure the WebDAQ for communication over a wireless network. With the WebDAQ
connected through the wired connection, perform the following procedure.
1. Connect an approved WiFi adapter to the USB port on the WebDAQ rear panel. A list of WiFi adapters
approved for use with WebDAQ Series hardware is available on our website.
2. Open the WebDAQ web interface in a browser window and go to the Device window, Network tab.
3. Select WiFi. Once the list of available networks updates, select the wireless network that you want toconnect to, and enter the password, if any. If the connection is successful, the selected wireless network
will show above this list with a checkmark next to it. You can click on the selected network to open a WiFi
Network Settings dialog box where you can forget the current network or configure the IP address type
(DHCP/Link-Local or Stac).
4. Disconnect the Ethernet cable from the LAN connection. Wait a few seconds and refresh the browser
window.
Changing to a wireless network may require a reboot

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WebDAQ 504 User’s Guide
If a connection cannot be established after changing the network, you may need to reboot the operating system
and restart the WebDAQ using the Power button.

Configuring the network router for communication across networks
To communicate with the WebDAQ over the internet from a computer connected to a different network, you mustchange the network configuration of the network router.
Caution! This procedure should only be performed by a network administrator or computer professional.
Incorrect settings can significantly disrupt a network.
In the following procedure, the WebDAQ is installed on the host LAN, the computer is installed on the client LAN,and it is assumed that you have successfully connected the device to a local network.
1.
2.
3.

4.

Determine the IP address of the WebDAQ – open the Device window from the web interface, and notethe IP Address value on the Network Settings tab.
Configure your router so that the address determined above is a static address. The procedure foraccomplishing this varies between routers; refer to your router documentation for instructions.
Configure the firewall/router to forward an unused port to port 80 on the WebDAQ at the IP addressconfigured for the device. Note the static IP address assigned to the router – this is referred to as the
WAN address.
To access your WebDAQ from a remote location, enter the WAN address followed by the port selected
above preceded by a colon in the web browser. The format of the address entered in the browser is:
00.000.00.00:00000 (WAN address of router:port selected for the WebDAQ).

Security
Use the web interface to set the level of access to the website and to change the administrator password.
•••

High: access to the web page requires a password.
Medium: access to the web page is permitted for any user, and data can be read by any user, but changes
to the device configuration or files require a password.
Off: full access is permitted for all users; no password is required.

By default, security access is set to "Off", and the administrator password is set to "admin". To change the security
level or password, open the web interface and go to the Device window, Security tab. Use the device Reset button
to restore security settings to factory default values.

Restoring factory default settings
To restore network configuration and security settings to the factory default values, use a paper clip to press the
CONFIG RESET button. When pressed, the default network and security settings are written to the device and theWebDAQ is rebooted.
Factory default settings.

Parameter
IP address
Subnet mask
Gateway
DHCP settingSpecification
192.168.0.101
255.255.255.0
192.168.0.1
DHCP + link-local enabled

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WebDAQ 504 User’s Guide
Parameter
Security level
Password for the admin accountPassword for the share accountSpecification
Off
Admin (case-sensitive)
Share (case-sensitive)
Webdaq-xxxxxx, where xxxxxx is the last 6 digits of the MAC address(printed on the label on the underside of the device)Device name

The network settings, security level, user account passwords and device name can be changed with the WebDAQ
web interface.
Shared folders and mapped drives are reset when factory defaults are restored.

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

Figure 2. WebDAQ 504 functional block diagram

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WebDAQ 504 User’s Guide

Front panel components

1

Screw terminal

2

BNC connectors

Screw terminal (Digital connections)
Connect up to four digital I/O lines (DIO0 to DI03) to the detachable screw terminal.

Figure 4. Screw terminal pinout.

The digital ground (GND) terminals provide a common ground for the digital bits.
The digital I/O lines are electrically isolated from the analog circuits. Each bit is individually configurable for input
or output, and features Schmitt trigger inputs and open drain outputs. All DIO channels are pulled high to 5 V.
Any digital bit can be configured with the web interface as a trigger to start or stop an acquisition, to trigger an
alarm and be driven high or low when an alarm occurs or be driven high or low when an event condition occurs.

BNC Connectors (Analog connections)
Connect up to four analog inputs to the BNC connectors (AI0+/AI0– to AI3+/AI3–). All analog inputs are
simultaneously sampled at rates of up to 51.2 kS/s per channel.

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WebDAQ 504 User’s Guide

Figure 5. BNC connector pinout.

The center pin of the connector (AI+) provides the DC excitation (when enabled) and positive input signal
connection. The shell of the connector (AI–) provides the excitation return path and AC ground reference.
Use the web interface to individually configure each input for voltage or Integrated Electronic Piezoelectric (IEPE)
sensor measurements. IEPE sensor types include acceleration, sound pressure, velocity, and force. Voltage
channels can be configured for AC or DC coupling. IEPE channels are automatically configured for AC coupling. Aninternal excitation source current is automatically enabled for IEPE sensor types.

Analog signal connections
You can connect ground-referenced or floating signal sources to the WebDAQ 504. Use a floating connection tominimize ground noise. If you make a ground-referenced connection between the signal source and the WebDAQ
504, make sure the voltage on the AI– shell is in the common-mode range to ensure proper operation. The AI- shellis protected against accidental contact with overvoltage within the overvoltage protection range. Refer to theSpecifications chapter for more information about operating voltages and overvoltage protection. The figure
below shows a diagram for connecting a grounded signal source to the WebDAQ 504.

Figure 6. Connecting a grounded IEPE sensor.

The figure below shows a diagram for connecting a floating signal source to the WebDAQ 504.

Figure 7. Connecting a floating IEPE sensor.

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WebDAQ 504 User’s Guide

Analog input circuitry
The analog input channels are referenced to chassis ground through a 50 Ω resistor. To minimize ground noise,make sure the chassis ground is connected to earth ground. The input signal on each channel is buffered,conditioned, and then sampled by a 24-bit Delta-Sigma ADC.

Figure 8. Input circuitry for one channel.

Overvoltage protection
WebDAQ 504 provides 30 V overvoltage protection for each channel.

AC/DC coupling
Use the web interface to configure voltage channels for AC or DC coupling. Configure for DC if the signal has nooffset voltage or if the DC content of the acquired signal is not important.
AC coupling is automatically enabled for IEPE channels to remove any DC offset from the measurement.

Common-mode bias current
The WebDAQ 504 uses common-mode bias current to bias the current-liming diodes when IEPE current is turned
off. When the WebDAQ 504 is using grounded signal sources, the current causes an error that is dependent on theAI– lead impedance and is approximately 50 ppm of range and 15 ppm of reading per Ω of AI– impedance. The
common-mode bias current causes an error only with grounded sources and is not an issue with floating signal
sources. For best accuracy, use a floating connection or use low-impedance leads when connecting groundedsignal sources; refer to the connection diagram shown below.

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WebDAQ 504 User’s Guide
Figure 9. Measurement error introduced by common-mode bias current.

Data rates
The frequency of the master timebase (𝑓M) controls the data rate (𝑓s) of the WebDAQ 504. The internal mastertimebase frequency on the WebDAQ 504 is 13.1072 MHz. The data rates available on the WebDAQ 504 can becalculated with the following equation: 𝑓s = (𝑓M ÷ 256)/n, where n is any integer from 1 to 31. The data rate mustremain within the appropriate data rate range. Using the internal master timebase of 13.1072 MHz results in data
rates of 51.2 kS/s, 25.6 kS/s, 17.067 kS/s, and so on, down to 1.652 kS/s, depending on the value of n.

Anti-aliasing filters
The WebDAQ 504 uses a combination of analog and digital filtering to provide an accurate representation of inband signals while rejecting out-of-band signals. The filters discriminate between signals based on the frequency
range, or bandwidth, of the signal. The three important bandwidths to consider are the passband, the stopband,and the alias-free bandwidth.
The WebDAQ 504 represents signals within the passband, as quantified primarily by passband flatness and phasenonlinearity. All signals that appear in the alias-free bandwidth are either unaliased signals or signals that havebeen filtered by at least the amount of the stopband rejection.

PassbandThe signals within the passband have frequency-dependent gain or attenuation. The small amount of variation ingain with respect to frequency is called the passband flatness. Digital filters adjust the frequency range of the
passband to match the data rate, so the amount of gain or attenuation at a given frequency depends on the data
rate. The figure below shows typical passband response for the WebDAQ 504.

Figure 10. Typical passband response.

The figure below shows the passband at one data rate.

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WebDAQ 504 User’s Guide

Figure 11. AC cutoff frequency response.

StopbandThe filter significantly attenuates all signals above the stopband frequency. The primary goal of the filter is toprevent aliasing. Therefore, the stopband frequency scales precisely with the data rate. The stopband rejection is
the minimum amount of attenuation applied by the filter to all signals with frequencies within the stopband.

Alias-free bandwidth
Any signal that appears in the alias-free bandwidth of the WebDAQ 504 is not an aliased artifact of signals at ahigher frequency. The alias-free bandwidth is defined by the ability of the filter to reject frequencies above thestopband frequency, and it is equal to the data rate minus the stopband frequency.

Rear panel components

Figure 12. Rear panel

1

External power connector

4

LED indicators (4)7Ethernet connector

2Power button

5

SD card slot

8

Ground connector

3

Function button

6

Factory reset button(recessed)

9

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WebDAQ 504 User’s Guide

External power connector
Connect the external AC adapter to the connector labeled EXT PWR on the rear panel. Click here to jump to thepower specifications.

Power button
The button labeled POWER turns the WebDAQ device on and off. WebDAQ hardware is designed with a 2-pin
jumper (W1) that users can remove to continuously power the device. The behavior of the POWER button when
jumper W1 is installed or removed is listed in the following table.
Jumper W1 installed (factory default setting)•

When the device is off, press the POWER
button briefly to turn the device on.

•

When the device is on, press the POWER
button for approximately 1 second to shut
down the operating system and WebDAQ
hardware; release the button when the
POWER LED blinks yellow.
The operating system automatically powers
off the device at the end of the shutdown
procedure.
Press and hold the POWER button for
approximately 4 seconds to force the device
to power off. Any unsaved changes may belost when powering down using this method.

•

Jumper W1 removed• The device is always on as long as the power
adapter is connected and receiving power(Power-On Mode).

•

Press for approximately 1 second to reboot
the device; release the button when the
POWER LED blinks yellow.

Refer to Power-On Mode for the procedure to remove jumper W1 and enable Power-On mode.
The WebDAQ device can also be restarted or shut down using the web interface; refer to the WebDAQ help for
details.

Function button
The button labeled FUNC has two functions; it can be used to eject external media or to start/stop an acquisition.
••

Eject external media (default): Pressing the button unmounts all removable media so they can be safely
removed from the device.
Start or stop an acquisition (requires configuration with the web interface): When configured, pressing
this button starts an acquisition, or stops an acquisition that is currently running.

Use the web interface to safely unmount removable media when present.
When removable media is plugged into the WebDAQ, the operating system opens it for writing. To safely remove
the media, you must unmount it first.
When a job is configured to log data to external media, pressing FUNC while the job is running will not eject themedia.

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WebDAQ 504 User’s Guide
The MEDIA LED is steady green when all media is unmounted and safe to remove, and off when all media isremoved.

LED status indicators
The WebDAQ has four LEDs on the rear panel that indicate the status of power and host communications. The
following table defines the LED states during normal operation.
LED states – normal operating mode.

Label
1: POWER

2: STATUS

State

Description

Steady yellow
Steady green
Blinking yellow
Off
Blinking yellow
Steady green
Flashing green 100 ms
on/2s off)

Device is booting up
Device boot is successful.
Device is shutting down.
Device is off.
Device is configuring hardware.
Hardware configuration is complete.

Blinking heartbeat
Blinking green
Off
3: ERROR

Blinking yellow
Off
Blinking yellow

4: MEDIA

Steady yellow
Blinking green
Steady green

Waing for a scheduled start condition to be met.
Scheduled start condition is met; waiting for job start
condition to be met.
Data is being acquired (job start condion is met).
No error detected.
Error condition is detected. This LED blinks even when
the software is configured to ignore the error.
Error state is cleared when the next schedule starts.
No error detected.
A job is configured to log to external media, but the job
hasn't started yet; pushbutton will not let you eject
media.
External media is inserted into the SD card slot or USB
storage port.
Currently logging to an external SD card or USB storage
device.
Media has been made safe for removal using thefunction button, but has not been removed.

WebDAQ LEDs behave differently when software is updated on the device. The following table defines the LED
states during a software update.
LED states – software update mode.

LED
All LEDs
POWER
STATUS
ERROR

State
Solid yellow
Blinking yellow
Blinking green
Blinking yellow
Blinking green

Description
Software update is starting
Software update is running
Update file is located; device is being updated
Update file cannot be located; insert media with update
fileUpdate is successful; device will reboot in approximately
5 seconds

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WebDAQ 504 User’s Guide
Blinking yellow

Update failed; user must retry

Refer to Updating WebDAQ firmware for more information about WebDAQ firmware.

SD card slot
The SD slot accepts SD (Secure Digital), SDHC, SDXC, MMC, and TransFlash memory cards. Memory cards can beejected using the web interface or the hardware FUNC button, unless the button is configured to start/stop an
acquisition.
When removable media is plugged into the WebDAQ, the operating system opens it for writing. Use the FUNC
button or web interface to unmount the SD card before removing.

Factory reset button
The recessed button labeled CONFIG RESET restores factory default settings. When pressed, the default settings
are written to the device and the WebDAQ is rebooted. Refer to the Restore factory default settings section for alist of the default settings that are restored.

Ethernet connector
The WebDAQ has one 10 Base-T/100 Base-TX, auto-negotiation, high-speed communication port. The port
connector is an RJ-45, eight-position connector. The Ethernet port accepts shielded or unshielded twisted paircable. The maximum communication distance without using a repeater is 100 m (328 ft). For CE compliance themaximum distance is 3 m (9.84 ft).

Ground connector
The WebDAQ ships with a ground screw in the connector labeled #6-32. To ground the WebDAQ chassis, attach aring lug to a 14 AWG (1.6 mm) wire. Connect the ring lug to the grounding screw on the WebDAQ rear panel.
Attach the other end to a safety ground.

USB connectors
The two high-speed USB ports can be used for connections to a mass storage device and approved WiFi adapter.
When removable media is plugged into the WebDAQ, the operating system opens it for writing. Use the FUNC
button or web interface to unmount the USB device before removing.
Use a self-powered hub when external media requires higher current
USB-powered hard drives may use an excessive amount of current during operation. The WebDAQ device could
shut down or experience other errors if the power requirements of a connected device exceed the power
available. Use a self-powered hub if the current requirement of external media exceeds 500 mA.
We recommend that you connect USB-powered hard drives before powering up the WebDAQ.

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WebDAQ 504 User’s Guide

Logging data
You can log up to 3 GB of data to internal WebDAQ storage. To generate larger data files, log data to external
media with a storage capacity suitable for the acquisition. USB drives and SD cards are available in different fileformats, and OS support for each format varies. WebDAQ supports FAT32, exFAT, ext2/3/4, and NTFS file systems.
When generating large data files with Windows or Mac, or transferring files between operating systems, werecommend using external media formatted with the exFAT file system, such as an SDXC memory card. Whenrunning Linux, use external media formatted with the ex2/ex3/ex4 file system. Refer to the WebDAQ help FAQ for
more information about file formats.
File too large error
If you generate data that exceeds the capacity of the selected storage location, a "File too large" error is returned
and the acquisition stops. To avoid interruptions, select a storage location with a large capacity.
Logging data to external media
Acquiring data at high speeds can generate large file sizes. If you expect to acquire a large amount of data to asingle file when logging to external media, do not use media formatted with the FAT32 file system. FAT32 is limited
to a 4 GB maximum file size. If the log file on FAT32 media grows beyond that size, a "File too large" error isreturned and the acquisition stops. Before starting a logging session of this type, reformat the media using a
different file system such as NTFS.

Power-On Mode
WebDAQ Series hardware can be configured to start automatically when power is applied, instead of requiring
users to press the POWER button. This is useful if the WebDAQ is operating in a remote location and a power loss
occurs. This "power-on mode" is enabled by removing a 2-pin jumper (labeled W1) from the WebDAQ circuitboard.
When jumper W1 is removed, the device does not shut down completely unless the power adapter is unplugged
from the device or power source.
Perform the procedure below to remove jumper W1 from the WebDAQ circuit board and enable power-on mode.
Caution! The discharge of static electricity can damage some electronic components. Before removing theWebDAQ device from its housing, ground yourself using a wrist strap or touch the computer chassis orother grounded object to eliminate any stored static charge.
1.
2.
3.
4.
5.
6.
7.

Power down the WebDAQ device and disconnect the power supply.
On the rear panel, remove the Ethernet cable, power cable, SD card, and any USB devices.
Remove the #6-32 ground screw.
Remove the nut and washer from the EXT PWR connector.
Remove the two front panel bezel screws and remove the front bezel.
Slide out the circuit board with the front panel intact.
Remove jumper W1 from the specified location shown below.

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WebDAQ 504 User’s Guide

8. Slide the circuit board back into the enclosure.
9. Attach the front bezel and secure with the two bezel screws removed in step 5.
10. Secure the power connector with the nut and washer (removed in step 4) to the power connector, andattach the ground screw, Ethernet and power cables, and any USB devices.
To automatically run a schedule when the WebDAQ powers up, enable the “Automatically start schedule on
system startup” option on the Schedule Settings dialog box of the web interface. If a power cycle occurs, theschedule will restart from the beginning, regardless of which job was running when the power was lost. In order toretain the data from each schedule start, make sure to set the logging option for each job to “Append Date/Time
to File Name” so that each run after power loss creates a new data file rather than overwriting the original file.
Refer to the WebDAQ help for details about how to configure schedule and logging options.
Enabling power-on mode with a complex or date/time triggered schedule
When running a complex or date/time-triggered schedule with both power-on mode and auto start schedule
enabled, be aware that the schedule may not run automatically after a power cycle if the date or time trigger is nolonger valid. In this case, the user may still access the WebDAQ remotely to modify the start settings.

Replacing the battery
A button cell lithium battery provides the me reference for WebDAQ hardware when the device is powered off.
The average lifespan of the battery is approximately 10 years.
Caution! The discharge of static electricity can damage some electronic components. Before removing theWebDAQ from its housing, ground yourself using a wrist strap or touch the computer chassis or othergrounded object to eliminate any stored static charge.
1. Power down the WebDAQ device and disconnect the power supply.
2. On the rear panel, remove the Ethernet cable, power cable, SD card, and any USB devices.
3. Remove the #6-32 ground screw.
4. Remove the nut and washer from the EXT PWR connector.
5. Remove the two front panel bezel screws and remove the front bezel.
6. Slide out the circuit board with the front panel intact.
7. Remove the battery by sliding it forward toward the slot and replace with a 3 V lithium coin cell battery.
8. Slide the circuit board back into the enclosure.
9. Attach the front bezel and secure with the two bezel screws removed in step 5.
10. Secure the power connector with the nut and washer removed in step 4, to the power connector, attach
the ground screw, Ethernet and power cables, and any USB devices.
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WebDAQ 504 User’s Guide
Set the device system clock from the Device window, Device Info tab on the web interface.

Updating WebDAQ firmware
Device firmware is bundled with the operating system, web server, and documentation in a software update(*.swu) file. Firmware updates are posted on the Resource Center page and are available for download.
Use the web interface to install the *.swu update file. Open a browser window and enter http://webdaqxxxxxx.local/Help, where xxxxxx is the last 6 digits of the MAC address – see the label on the bottom of theenclosure. In the web server’s Help, refer to the “Updating WebDAQ Firmware” topic or FAQ for instructions.

Calibrating the hardware
The Digilent Test department performs the initial factory calibration. Contact Digilent when calibration is required.
The recommended calibration interval is one year.

Specifications
All specifications are subject to change without notice.
Typical for 0 °C to 50 °C unless otherwise specified.

Analog input
Table 1. Analog input specifications.

Parameter
Number of channels
ADC resolution
Type of ADC
Sampling mode

Condition

Internal master timebase(𝑓M)

Frequency

Specification
4 analog input channels
24 bits
Delta-Sigma (with analog prefiltering)
Simultaneous
13.1072 MHz

Accuracy±50 ppm max–3 dB

1.652 kS/s min
51.2 kS/s max(𝑓M ÷ 256)/n, where n is any integer from 1 to 31
AC/DC; software-selectable
0.5 Hz–0.1 dB

4.6 Hz max

Data rate range (𝑓s)Data rates (𝑓s)Input couplingAC cutoff frequency
Input range±5 V±5 Vpk min±5.1 Vpk typ±5.2 Vpk max

AC voltage fullscale
range
Common-mode voltage
range
IEPE excitation current;
software-selectable
on/off
Power-on glitch

AI– to earth ground±2 V max
2.0 mA min
2.1 mA typ
90 μA for 10 μs

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WebDAQ 504 User’s Guide
Parameter
IEPE compliance voltage1
Overvoltage protection,with respect to chassis
groundCondition
Signal source connected
to AI+ and AI–±30 V

Low-impedance source
connected to AI+ and AI––6 V to 30 V

Input delay
Gain drift
Offset drift
Channel-to-channel
matching
PassbandPhase nonlinearity
StopbandSpecification
19 V max

Phase (fin in kHz)

(40 + 5/512)/𝑓s + 2.6 μs
0.14 mdB/°C (16 ppm/°C) typ0.45 mdB/°C (52 ppm/°C) max
19.2 μV/°C typ
118 μV/°C max
fin × 0.045° + 0.04 max

Gain

0.01 dB typ
0.04 dB max

Frequency

0.45 × 𝑓s

Flatness (𝑓s = 51.2 kS/s)±40 mdB (pk-to-pk max)

𝑓s = 51.2 kS/s
Frequency±0.45° max
0.55 × 𝑓s

Rejection

100 dB

Alias-free bandwidth
Oversample rate
Crosstalk

1 kHz

CMRR

fin ≤ 1 kHz

SFDR

fin = 1 kHz, –60 dBFS
Differential

Input impedance

AI– (shield) to chassis
ground0.45 × 𝑓s
64 × 𝑓s–110 dB
40 dB min
47 dB typ120 dB
305 kΩ
50 Ω

Table 2. Measurement accuracy specifications.

Measurement Conditions
Max (0 °C to 50 °C)
Calibrated
Typ (25 °C ±5 °C)

Percent of Reading (Gain Error)±0.34% (±0.03 dB)±0.07% (±0.006 dB)

Percent of Range (Offset Error)2±0.14% (±7.1 mV)±0.01% (±0.5mV)

Table 3. Idle channel and noise density specifications.

Idle Channel
Noise
Noise density

51.2 kS/s
97 dBFS
50 µVrms
310 nV/√Hz

25.6 kS/s
99 dBFS
40 µVrms
350 nV/√Hz

2.048 kS/s
103 dBFS
25 µVrms
780 nV/√Hz

1 If you are using an IEPE sensor, use this equation to make sure your configuration meets the IEPE compliance voltage range:(Vcommon-mode + Vbias ± Vfull-scale) must be 0 to 19, where:
Vcommon-mode is the common-mode voltage applied to the WebDAQ 504.
Vbias is the bias voltage of the IEPE sensor.
Vfull-scale is the full-scale voltage of the IEPE sensor.
2 Range = 5.1 Vpk.
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WebDAQ 504 User’s Guide

Table 4. Total harmonic distortion (THD) specifications.

Input Amplitude

Condition–1 dBFS

Input amplitude

Intermodulation distortion (–1dBFS)

Specification
1 kHz: –95 dB
8 kHz: –87 dB–20 dBFS

1 kHz: –95 dB
8 kHz: –80 dB

DIN 250 Hz/8 kHz
4:1 amplitude ratio–80 dB

CCIF 11 kHz/12
kHz 1:1 amplitude ratio–93 dB

Digital input/output
Table 5. Digital input/output specifications.

Parameter
Digital type
Number of I/O
Configuration
Power on conditions
Pull-up configuration
Input frequency range
Input high voltage threshold
Input low voltage threshold
Schmitt trigger hysteresis
Input high voltage limit
Input low voltage limit
Output voltage range
Output off state leakage current
Output sink current capability
Output transistor on-resistance(drain to source)

Specification
CMOS (Schmitt trigger) input / open drain output
One port of 4 bits
Each bit can be independently configured for input or output
Power on reset is input mode
Each bit is pulled up to 5 V with a 100 kΩ resistor
DC – 10 kHz3
1.9 V min, 3.6 V max
2.3 V max, 1.0 V min
0.6 V min, 1.7 V max
15 V max–0.5 V absolute min
0 V recommended min
0 V to +5 V (no external pull-up resistor)
0 V to +15 V max4
10 µA max
100 mA max (continuous) per output pin
1.6 Ω

3 Applying a signal with a frequency higher than this specification will adversely affect system performance and could cause errors.
4 The external pull-up resistor is connected between the digital output bit and an external supply. Adding an external pull-up resistor connects

it in parallel with the internal 100 kΩ pull-up resistor of that particular digital input/output bit to the internal 5 V supply. Careful consideration
should be made when considering the external pull-up resistor value and the resultant pull-up voltage produced at the load.

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Page 20 of 26

WebDAQ 504 User’s Guide

Network
Ethernet connection
Table 6. Ethernet connection specifications.

Parameter
Ethernet typeCommunication rates
Connector
Cable length
Additional parameters

Specification
100 Base-TX
10 Base-T
10/100 Mbps, auto-negotiated
RJ-45, 8 position
100 meters (328 feet) max
For CE compliance the max length is 3 meters (9.84 feet)
HP Auto-MDIX support

Network Configuration
Table 7. Network configuration.

Parameter
Network IP configuration

Network device name
Network name publication

User accounts

Specification
DHCP, link-local, static
DHCP may be disabled by the user and a static IP address assigned
If DHCP is enabled but is unsuccessful at obtaining an IP address the device
will fall back to link-local and request the IP address 169.254.100.100.
The name used for detecting the device using mDNS (zero-conf). This namemay be changed using the web interface.
By mDNS
There are two built-in user accounts:• admin• shareThese accounts are case-sensitive and cannot be changed using the webinterface.

Factory default settings
Table 8. Factory default settings.5

Parameter
Factory default IP address
Factory default subnet mask
Factory default gateway
Factory default DHCP setting
Factory default password foradmin accountFactory default password forshare accountFactory default device nameSpecification
192.168.0.101
255.255.255.0
192.168.0.1
DHCP + link-local enabledadmin
Passwords are case sensitive and can be changed using the web interface.
share
Passwords are case sensitive and can be changed using the web interface.
webdaq-xxxxxx, where xxxxxx is the last 6 digits of the MAC address(printed on the label on the underside of the device).

5 Shared folders and mapped drives are reset when factory defaults are restored.

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WebDAQ 504 User’s Guide

Processor / Memory
Table 9. Processor / memory specifications.

Parameter

Specification
Type: Quad core Broadcom BCM2837
Speed: 1.2 GHz
RAM: 1 GB LPDDR2Flash: 4 GB eMMC (3 GB available for user data storage)

Microprocessor
MemoryUSB ports
Table 10. USB specifications.6

Parameter
Number of USB ports
USB device type
Device compatibility

SpecificationTwo
USB 2.0 (high-speed)
USB 1.1, USB 2.0, USB 3.0

SD memory card slot
Table 11. SD card specifications.

Parameter
Memory card type
File systems supported

Specification
SD, SDHC, SDXC, MMC, TransFlash
FAT16, FAT32, exFAT, ext2/3/4, NTFS

LED indicators
Table 12. LED specifications – normal operating mode.

Label
1: POWER

2: STATUS

State
Steady yellow
Steady green
Blinking yellow
Off
Blinking yellow
Steady green
Flashing green 100 ms
on, 2s of
Blinking heartbeat

Description
Device is booting up.
Device boot is successful.
Device is shutting down.
Device is off.
Device is configuring hardware.
Hardware configuration is complete.
Waing for the schedule start condition to be met. 7
The configured schedule start condition is met; waiting forjob start condition to be met.7

6 The USB ports are provided for connection to a mass storage device or approved WiFi adapter.
7 Use the WebDAQ software to configure start and stop settings for jobs and schedules.

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WebDAQ 504 User’s Guide
Label

State
Blinking green
Off

3: ERROR

4: MEDIA

Blinking yellow

Description
The configured job start condition is met – the job is
running.7
Device is off.
Error condition is detected. LED blinks even when thesoftware is configured to ignore the error.
Error state is cleared on the next schedule start.

OffNo error is detected, or the device is off.

Blinking yellow

A job is configured to log to external media, but the job
hasn't started yet; push button will not let you eject media.

Steady yellow

External media is inserted into the SD card slot or USB
storage port.

Blinking green

Currently logging to an external SD card or USB storage
device.

Steady green

Media has been made safe for removal using the FUNC
button but is still inserted in the device.

Off

No external media is detected, or the device is off.

Table 13. LED specifications – software update mode.

LED
All LEDs
1. POWER
2. STATUS

3. ERROR

State
Solid yellow
Blinking yellow
Blinking green
Blinking yellow
Blinking green
Blinking yellow

Description
Software update is starting.
Software update is running.
Update file is located; device is being updated.
Update file cannot be located; insert media containing the
update file.
Update is successful; device reboot in approximately 5
seconds.
Update failed; user must retry.

Push buttons
Table 14. Push button specifications.

Component

LabelPower button

POWER

Description
W1 jumper installed (factory default) 8• When device is off; press briefly to turn the deviceon• When device is on:o Press for ~1 second to shut down thedevice; release the button when the
POWER LED blinks yellow
o Press and hold ~4 seconds to force thedevice to power off
W1 jumper removed8• Device will always be on if power is applied

8 Refer to this circuit board image for the location of the W1 jumper.

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WebDAQ 504 User’s Guide
Component

Label

Function button

FUNC

Factory reset button

CONFIG RESET

Description• Press for ~1 second to reboot the device; release
the button when the POWER LED blinks yellow
Dual function:• Ejects, or safely unmounts, all removable media forsafe removal from the device (default)• This function is disabled when a job that uses
external media is running• The MEDIA LED is steady green when all media isunmounted but still inserted in the device• Starts or stops an acquisition; requires
configuration via the web interface
Restores network settings to factory default values; refer tothe Factory default settings table for values.

Ground connector
Table 15. Ground connector specifications.

Component
Ground connector

Label
#6-32

Description
Connector port for the #6-32 ground screw

Power
Table 16. Power specifications.

Parameter
Input voltage
Input wattage
External power
adapter

Power behavior

Conditions
Center positive

ATS018T-W090V 18W 9
W1 jumper installed(factory default)
W1 jumper removed

Battery

Battery replacement

Specification
6 VDC to 16 VDC
4 W typ, 10 W max
Adapter Technology ATS018T-W090V 18W adapter
included. 9V, 2.2A, 110 VAC to 240 VAC input range
required.
Soft power on using the momentary power button; device
can turn its power off to shut down. Device does notresume operation if power is lost.
Device is always on if power is applied. Power button
functions only as a reboot button.
One 3 V button cell lithium battery required to maintaintime of day clock when device is powered off.
Panasonic BR-1225 3V lithium coin cell battery or
equivalent; user-replaceable.
Refer to the Replacing the Battery section for the
replacement procedure.

9 If using a different supply, ensure that it has a positive center pin.

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Page 24 of 26

WebDAQ 504 User’s Guide

Mechanical
Table 17. Mechanical specifications.

Parameter
Dimensions(L × W × H)
WeightSpecification
158.8 × 146.1 × 38.1 mm (6.25 × 5.75 × 1.50 in.)
178.8 × 146.1 × 38.1 mm (7.04 × 5.75 × 1.50 in.) includes BNC connectors
680 g (1.50 lb)

Shock and vibration
Table 18. Shock and vibration specifications.

Parameter
Shock (IEC 60068-227)
Random Vibration(IEC 60068-2-64)

Conditions
Operational

Specification
30 g peak, half-sine, 11 ms pulse
50 g peak, half-sine, 11 ms pulse
18 shocks at 6 orientations
5 to 500 Hz, 0.3 grms
5 to 500 Hz, 2.4 grms

Nonoperating
Operational
Nonoperating

Environmental
Table 19. Environmental specifications 10

Parameter
Operatingtemperature range
Storage temperature
range
Ingress protection
Operating humidity
Storage humidity
Maximum altitude
Pollution DegreeSpecification
0 °C to 50 °C–40 °C to 85 °C
IP30
10% to 90% RH, noncondensing
5% to 95% RH, noncondensing
2,000 m (6,562 ft)
2

Safety voltages
Connect only voltages that are within the limits specified in this table.
Table 20. Safety specifications

Parameter

Conditions

Voltage limits

Channel-to-earth
groundChannel-to-channel

Isolation

Specification±30 V max, Measurement Category I
None

10 WebDAQ operation is intended for indoor use only, but may be used outdoors if installed in a suitable enclosure.

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WebDAQ 504 User’s Guide
Channel-to-earth
groundNone

Measurement Category I is for measurements performed on circuits not directly connected to the electrical
distribution system referred to as MAINS voltage. MAINS is a hazardous live electrical supply system that powers
equipment. This category is for measurements of voltages from specially protected secondary circuits. Suchvoltage measurements include signal levels, special equipment, limited-energy parts of equipment, circuits
powered by regulated low-voltage sources, and electronics.
Measurement Categories CAT I and CAT O are equivalent. These test and measurement circuits are for othercircuits not intended for direct connection to the MAINS building installations of Measurement Categories CAT II,
CAT III, or CAT IV.
Caution! Do not connect the WebDAQ 504 to signals or use for measurements within Measurement
Categories II, III or IV.

Signal connectors
Table 21. Screw terminal specifications.

Parameter

Specification
36-position spring terminal for thermocouple connections
6-position screw terminal for digital connections
14 to 30 AWG copper conductor wire with 5 to 6 mm (0.20 to 0.24 in.) of insulation
stripped from the end
16 to 28 AWG copper conductor wire with 7 mm (0.28 in.) of insulation stripped fromthe endConnector types
Screw terminal wiring
Spring terminal wiring

Screw terminal
Table 22. Screw terminal pinout.

#
1
2
3

Label
GND
DIO0
DIO1

Terminal
Use
Digital ground
Digital bit 0
Digital bit 1

#
4
5
6

Label
DIO2
DIO3
GND

Terminal
Use
Digital bit 2
Digital bit 3
Digital ground

Label
AI2+
AI2–
AI3+
AI3–

Terminal
Use
Channel 2 HI
Channel 2 LO
Channel 3 HI
Channel 3 LO

BNC connectors
Table 23. BNC connector pinout.

#
1
2
3
4

Label
AI0+
AI0–
AI1+
AI1–

Terminal
Use
Channel 0 HI
Channel 0 LO
Channel 1 HI
Channel 1 LO

#
5
6
7
8

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