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WebDAQ 316 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 316 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 316 spring
terminals. 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 316 are properly insulated fromhuman contact.

When device terminals are hazardous voltage LIVE (>42.4Vpk/60 VDC), you must install a high voltage screw
terminal backshell (not included) to ensure that the terminals are not accessible and that the devices and circuits
connected to the WebDAQ 316 are properly insulated from human contact.
Hazardous locations: The WebDAQ 316 is not certified for use in hazardous locations.

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WebDAQ 316 User’s Guide

Introducing the WebDAQ 316
The WebDAQ 316 is part of the WebDAQ Series of Internet enabled data loggers. WebDAQ 316 is a thermocouple
acquisition and logging device that provides the following features:
•
•
•
•
•
•
•
•
•
•
•
•

16 differential thermocouple inputs
75 S/s/ch sample rate
250 V channel-to-earth isolation
Overvoltage protection between any two thermocouple inputs
50/60 Hz noise rejection
Cold junction compensation (CJC)
Auto zero channel
Four bidirectional, isolated DIO (individually configurable for input trigger or output alarm)
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 a +9 VDC external supply (included)

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 316 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 316 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 316 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 316 has a built-in 10/100 BASE-T auto-negotiation, high-speed communication port. You can accessand configure your WebDAQ 316 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 316 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.

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 316 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 316 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 Static).
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
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.

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WebDAQ 316 User’s Guide

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

Specification

IP address

192.168.0.101

Subnet mask

255.255.255.0

Gateway

192.168.0.1

DHCP setting

DHCP + link-local enabled

Security level

Off

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WebDAQ 316 User’s Guide
Password for the admin accountadmin (case-sensitive)

Password for the share accountshare (case-sensitive)

Device namewebdaq-xxxxxx, where xxxxxx is the last 6 digits of the MAC address(printed on the label on the underside of the device)

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 316 functional block diagram

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WebDAQ 316 User’s Guide

Front panel components

Figure 3. Front Panel

1

Screw terminal

2

Spring Terminal

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 areelectrically 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.

Spring terminal (Analog connections)
Connect up to 16 thermocouple or voltage inputs (TC0+/TC0– to TC15+/TC15–) and two common reference
connections (COM) to the 36-position detachable spring terminal.
Caution! We strongly recommend that you ground yourself using a wrist strap before handlingthermocouple sensors.

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WebDAQ 316 User’s Guide

Figure 5. Spring terminal pinout.

Thermocouple connections
A thermocouple consists of two dissimilar metals that are joined together at one end. When the junction of themetals is heated or cooled, a voltage is produced that correlates to temperature. The WebDAQ 316 supports type
J, K, S, R, B, E, T, N thermocouples (TC), and provides overvoltage protection between any two inputs. A typicalthermocouple connection is shown in the following figure.

Figure 6. Typical thermocouple connection

Connect the shield to a common mode voltage reference on the thermocouple. A valid reference is voltage within±1.2 V of all the connected thermocouples.

Minimizing thermal gradients
Changes in the ambient air temperature near the thermocouple connectors or a thermocouple wire conducting
heat directly to terminal junctions can cause thermal gradients. Observe the following guidelines to minimize
thermal gradients and improve system accuracy:•••

Use small-gauge thermocouple wire. Smaller wire transfers less heat to or from the terminal junction.
Run thermocouple wiring together near the spring terminal connector to maintain a consistenttemperature.
Avoid running thermocouple wires near hot or cold objects.

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WebDAQ 316 User’s Guide••

Minimize adjacent heat sources and air flow across the terminals.
Keep the ambient temperature as stable as possible.

Increasing the thermocouple length
If you need to increase the length of your thermocouple, use the same type of TC wires to minimize the error
introduced by thermal EMFs.

Analog input circuitry
Each channel passes through a differential filter and then is multiplexed and sampled by a 24-bit ADC. The
channels share a common ground (COM) that is isolated from the digital subsystem.
The circuitry for one thermocouple channel is shown here.

Figure 7. Input circuitry of one TC channel

Open thermocouple detection
Each channel has an open thermocouple detection (OTD) circuit which consists of a current source between the
TC+ and TC– terminals. If an open thermocouple is connected to the channel, the current source forces a full-scale
negative voltage across the terminals.

Input ImpedanceEach channel has a resistor that produces an input impedance between the TC and COM terminals. The gain andoffset errors resulting from the source impedance of connected thermocouples are negligible for mostapplications. Thermocouples with a longer lead length can introduce more significant errors.

Overvoltage protection
WebDAQ provides 30 V overvoltage protection between any two inputs.

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WebDAQ 316 User’s Guide

Thermocouple measurement accuracy
Thermocouple measurement errors depend partly on the type and accuracy of the thermocouple, the temperature
being measured, the resistance of the thermocouple wires, and the cold-junction temperature.
For increased accuracy, follow the guidelines in the Minimizing thermal gradients section, and use the auto zerochannel to compensate for offset errors.

Cold-junction accuracy
Heat dissipated by nearby heat sources can cause errors in thermocouple measurements by heating the WebDAQ
316 terminals to a different temperature than the cold-junction compensation sensor. Thermal gradient across theterminals can cause the terminals of different thermocouple channels to be at different temperatures, which
creates accuracy errors and affects the relative accuracy between channels.
The temperature measurement accuracy specifications include errors caused by the thermal gradient across the
WebDAQ 316 terminals for configuration with the terminals facing forward or upward.

Auto zero channel
The WebDAQ 316 has an internal auto zero channel to compensate for offset errors. When enabled, the WebDAQ
measures the autozero channel and subtracts that measurement from the measurement of each thermocouple
channel. Use the web interface to enable auto zero. WebDAQ 316 specifications assume that auto zero is enabled
and applied to every sample.

Rear panel components

Figure 8. 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 316 User’s Guide

External power connector
Connect the external AC adapter to the connector labeled EXT PWR on the rear panel. Power specifications arelisted in the Power section.

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)Jumper W1 removed•

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

•

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

•

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 thismethod.

•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 316 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

3: ERROR

4: MEDIA

State

Description

Steady yellow

Device is booting up

Steady green

Device boot is successful.

Blinking yellow

Device is shutting down.

Off

Device is off.

Blinking yellow

Device is configuring hardware.

Steady green

Hardware configuration is complete.

Flashing green 100 ms
on/2s off)

Waing for a scheduled start condition to be met.

Blinking heartbeat

Scheduled start condition is met; waiting for job start
condition to be met.

Blinking green

Data is being acquired (job start condion is met).

OffNo error detected.

Blinking yellow

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.

OffNo error detected.

Blinking yellow

A job is configured to log to external media, but the job
hasn't started yet; pushbutton 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 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

State

Description

All LEDs

Solid yellow

Software update is starting

POWER

Blinking yellow

Software update is running

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WebDAQ 316 User’s Guide

STATUSERROR

Blinking green

Update file is located; device is being updated

Blinking yellow

Update file cannot be located; insert media with update
file

Blinking green

Update is successful; device will reboot in approximately
5 seconds

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 thepower available. Use a self-powered hub if the current requirement of external media exceeds 500 mA.

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WebDAQ 316 User’s Guide
We recommend that you connect USB-powered hard drives before powering up the WebDAQ.

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 isreturned 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 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 "Filetoo 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.

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 316 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 startschedule enabled, be aware that the schedule may not run automatically after a power cycle if the date ortime trigger is no longer valid. In this case, the user may still access the WebDAQ remotely to modify thestart 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.
2.
3.
4.
5.
6.

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.

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WebDAQ 316 User’s Guide
7.

Remove the battery by sliding it forward toward the slot and replace it with a 3 V lithium coin cellbattery.
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.
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 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.

Thermocouple input
Table 1. Thermocouple input specifications

Parameter

Condition

Specification

Number of channels

16 thermocouple channels
1 internal auto zero channel
1 internal cold-junction compensation channel

ADC resolution

24 bits

Type of ADC

Delta-Sigma

Sampling mode

ScannedVoltage measurement
range±78.125 mV

Temperature
measurement ranges

Works over temperature ranges defined by NIST (J,K, T, E, N, B, R, S thermocouple types)

Timing mode

Automatically set foreither high-resolution or
highspeed mode basedon the requested scan••

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High resolution: requested scan rate is ≤1
Hz
High-speed: requested scan rate is >1 Hz

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WebDAQ 316 User’s Guide
Parameter

Condition

Specification

rate, regardless of thenumber of channels.
High-resolution

Conversion Time (per channel): 55 ms
Sample Rate (all channels): 1 S/s

High-speed

Conversion Time (per channel): 740 µs
Sample Rate: 75 S/s/ch

Timing mode

Common-mode voltage
range
Common-mode
rejection ratio (CMRR)

Input bandwidth
High-resolution noise
rejection

Channel-to-COM: ±1.2 V min
COM-to-earth ground: ±250 V
High-resolution mode at
DC and 50 to 60 Hz

Channel-to-COM: 100 dB
COM-to-earth ground: >170 dB

High-speed mode at 0 to
60 Hz

Channel-to-COM: 70 dB
COM-to-earth ground: >150 dB

High-resolution mode

14.4 Hz

High-speed mode

78 Hz

50 Hz and 60 Hz

60 dB

Overvoltage protection±30 V between any two inputs

Differential input
impedance

78 MΩ

Input current

50 nA

Input noise

High-resolution mode

200 nVrms

High-speed mode

7 µVrms

High-resolution mode

0.03% typ at 25 °C
0.07% typ at 0 °C to 60 °C
0.15% max at 0 °C to 60 °C

High-speed mode

0.04% typ at 25 °C
0.08% typ at 0 °C to 60 °C
0.16% max at 0 °C to 60 °C

High-resolution mode

4 µV typ, 6 µV max

High-speed mode

14 µV typ, 17 µV max

0 °C to 60 °C

Add 0.05 µV per Ω, when source impedance >50 Ω

Gain error

Offset error
Offset error from source
impedance
Cold-junction
compensation accuracy

Warm-up time

0.8 °C typ, 1.7 °C max
The device is lying flat or
facing upward, at aconstant ambient
temperature.

15 minutes recommended

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Temperature measurement accuracy
Measurement sensitivity represents the smallest change in temperature that a sensor can detect. It is a function ofnoise. The values assume the full measurement range of the standard thermocouple sensor per ASTM E230–87.
Table 2. Temperature accuracy specifications

Parameter

Condition
High-resolution mode

Measurement sensitivity
High-speed mode

Specification
Type J, K, T, E, N: <0.02 °C
Type B, R, S: <0.15 °C
Type J, K, T, E: <0.25 °C
Type N: <0.35 °C
Type B: <1.2 °CType R, S: <2.8 °C

The following figures show the errors for each thermocouple type when connected to the WebDAQ 316 with auto
zeroing performed. The figures display the maximum error over a full temperature range, and the typical error atroom temperature. The figures account for gain errors, offset errors, differential and integral nonlinearity,
quantization errors, noise errors, 50 Ω lead wire resistance, and cold-junction compensation errors. The figures do
not account for the accuracy of the thermocouple itself.

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WebDAQ 316 User’s Guide

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WebDAQ 316 User’s Guide

Digital input/output
Table 3. Digital input/output specifications

Parameter

Specification

Digital type

CMOS (Schmitt trigger) input / open drain output

Number of I/O

One port of 4 bits

Configuration

Each bit can be independently configured for input or output

Power on conditions

Power on reset is input mode

Pull-up configuration

Each bit is pulled up to 5 V with a 100 kΩ resistor

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WebDAQ 316 User’s Guide
Parameter

Specification

Input frequency range

DC – 10 kHz1

Input high voltage threshold

1.9 V min, 3.6 V max

Input low voltage threshold

2.3 V max, 1.0 V min

Schmitt trigger hysteresis

0.6 V min, 1.7 V max

Input high voltage limit

15 V max

Input low voltage limit–0.5 V absolute min
0 V recommended min

Output voltage range

0 V to +5 V (no external pull up resistor)
0 V to +15 V max2

Output off state leakage
current

10 µA max

Output sink current capability

100 mA max (continuous) per output pin

Output transistor on-resistance(drain to source)

1.6 Ω

Network
Ethernet connection
Table 4. Ethernet connection specifications

Parameter

Specification

Ethernet type

100 Base-TX
10 Base-T

Communication rates

10/100 Mbps, auto-negotiatedConnector

RJ-45, 8 position

Cable length

100 meters (328 feet) max
For CE compliance the max length is 3 meters (9.84 feet)

Additional parameters

HP Auto-MDIX support

1 Applying a signal with a frequency higher than this specification will adversely affect system performance and could cause errors.
2 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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WebDAQ 316 User’s Guide

Network configuration
Table 5. Network configuration

Parameter

Specification

Network IP configuration

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.

Network device name

The name used for detecting the device using mDNS (zero-conf). This namemay be changed using the web interface.

Network name publication

By mDNS

User accounts

There are two built-in user accounts:• admin• shareThese accounts are case-sensitive and cannot be changed using the webinterface.

Factory default settings
Table 6. Factory default settings 3

Parameter

Specification

Factory default IP address

192.168.0.101

Factory default subnet mask

255.255.255.0

Factory default gateway

192.168.0.1

Factory default DHCP setting

DHCP + link-local enabled

Factory default password foradmin account

admin
Passwords are case sensitive and can be changed using the web interface.

Factory default password forshare account

share
Passwords are case sensitive and can be changed using the web interface.

Factory default device namewebdaq-xxxxxx, where xxxxxx is the last 6 digits of the MAC address(printed on the label on the underside of the device).

Processor / Memory
Table 7. Processor / memory specifications

Parameter

Specification

Microprocessor

Type: Quad core Broadcom BCM2837
Speed: 1.2 GHz

MemoryRAM: 1 GB LPDDR2Flash: 4 GB eMMC (3 GB available for user data storage)

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

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WebDAQ 316 User’s Guide

USB ports
Table 8. USB specifications 4

Parameter

Specification

Number of USB ports

Two

USB device type

USB 2.0 (high-speed)Device compatibility

USB 1.1, USB 2.0, USB 3.0

SD memory card slot
Table 9. SD card specifications

Parameter

Specification

Memory card type

SD, SDHC, SDXC, MMC, TransFlash

File systems supported

FAT16, FAT32, exFAT, ext2/3/4, NTFS

LED indicators
Table 10. LED specifications – normal operating mode

Label

1: POWER

2: STATUS

3: ERROR

State

Description

Steady yellow

Device is booting up.

Steady green

Device boot is successful.

Blinking yellow

Device is shutting down.

Off

Device is off.

Blinking yellow

Device is configuring hardware.

Steady green

Hardware configuration is complete.

Flashing green 100 ms
on, 2s of

Waiting for the schedule start condition to be met. 5

Blinking heartbeat

The configured schedule start condition is met; waiting forjob start condition to be met.5

Blinking green

The configured job start condition is met – the job is
running.5

Off

Device is off.

Blinking yellow

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.

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

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4: MEDIA

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 11. LED specifications – software update mode

LED

State

Description

All LEDs

Solid yellow

Software update is starting.

1. POWER

Blinking yellow

Software update is running.

Blinking green

Update file is located; device is being updated.

Blinking yellow

Update file cannot be located; insert media containing the
update file.

Blinking green

Update is successful; device reboot in approximately 5
seconds.

Blinking yellow

Update failed; user must retry.

2. STATUS

3. ERROR

Push buttons
Table 12. Push button specifications.

Component

Label

Description

Power button

POWER

W1 jumper installed (factory default)6• 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 removed6• Device will always be on if power is applied• Press for ~1 second to reboot the device; release
the button when the POWER LED blinks yellow

Function button

FUNC

Dual function:• Ejects, or safely unmounts, all removable media
for safe removal from the device (default)

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

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WebDAQ 316 User’s Guide•••
Factory reset
buttonThis 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; referto the Factory default settings table for values.

CONFIG RESET

Ground connector
Table 13. Ground connector specifications

Component

Label

Description

Ground connector#6-32

Connector port for the #6-32 ground screw

Power
Table 14. Power specifications

Parameter

Conditions

Specification

Input voltage

Center positive

6 VDC to 16 VDC

Input wattage
External power
adapter

Power behavior

4 W typ, 10 W max
ATS018T-W090V 18W
7

Adapter Technology ATS018T-W090V 18W adapter
included. 9V, 2.2A, 110 VAC to 240 VAC input range
required.

W1 jumper installed(factory default)

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.

W1 jumper removed

Device is always on if power is applied. Power button
functions only as a reboot button.

Battery

One 3 V button cell lithium battery required to maintaintime of day clock when device is powered off.

Battery
replacement

Panasonic BR-1225 3V lithium coin cell battery or
equivalent; user-replaceable.
Refer to the Replacing the Battery section for the
replacement procedure.

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

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WebDAQ 316 User’s Guide

Mechanical
Table 15. Mechanical specifications

Parameter

Specification

Dimensions(L × W × H)

158.8 × 146.1 × 38.1 mm (6.25 × 5.75 × 1.50 in.)
177.0 × 146.1 × 38.1 mm (6.97 × 5.75 × 1.50 in.) includes spring terminal

Weight635 g (1.45 lb)

Environmental
Table 16. Environmental specifications 8

Parameter

Specification

Operatingtemperature range

0 °C to 50 °C max

Storage temperature
range–40 °C to 85 °C

Ingress protection

IP30

Operating humidity

10% to 90% RH, noncondensing

Storage humidity

5% to 95% RH, noncondensing

Maximum altitude2,000 m (6,562 ft)

Pollution Degree2

Safety voltages
Connect only voltages that are within the limits specified in this table.
Table 17. Safety specifications

Parameter

Conditions

Specification

Between any two
terminals±30 V max

Channel-to channel
isolation

None

Channel-to-earth
ground isolation

Continuous

60 VDC for analog inputs, 15 VDC for DIO, CAT I

Withstand

60 VDC, verified by a 5 second dielectric withstand test

Measurement Category I is for measurements performed on circuits not directly connected to the electrical
distribution system referred to as MAINS voltage. MAINS is a hazardous live electrical supply system that powers
equipment. This category is for measurements of voltages from specially protected secondary circuits. Such

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

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WebDAQ 316 User’s Guide
voltage 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 316 to signals or use it for measurements within Measurement
Categories II, III or IV.

Signal connectors
Table 18. Screw terminal specifications.

Parameter

Specification

Connector types

36-position spring terminal for thermocouple connections
6-position screw terminal for digital connections

Screw terminal wiring

14 to 30 AWG copper conductor wire with 5 to 6 mm (0.20 to 0.24 in.) of insulation
stripped from the end

Springwiring16 to 28 AWG copper conductor wire with 7 mm (0.28 in.) of insulation stripped fromthe endterminal

Screw terminal
Table 19. Screw terminal pinout.

Terminal

Terminal

#

Label

Use

#

Label

Use

1

GND

Digital ground

4

DIO2

Digital bit 2

2

DIO0

Digital bit 0

5

DIO3

Digital bit 3

3

DIO1

Digital bit 1

6

GND

Digital ground

Spring Terminal
Table 20. Spring terminal pinout.

Terminal

Terminal

#

Label

Use

#

Label

Use

1

NC

No connection

29

NC

No connection

2

TC0[+]

Channel 0 HI30

TC0[–]

Channel 0 LO

3

TC1[+]

Channel 1 HI

31

TC1[–]

Channel 1 LO

4

TC2[+]

Channel 2 HI

32

TC2[–]

Channel 2 LO

5

TC3[+]

Channel 3 HI

33

TC3[–]

Channel 3 LO

6TC4[+]

Channel 4 HI

34

TC4[–]

Channel 4 LO

7

TC5[+]

Channel 5 HI

35

TC5[–]

Channel 5 LO

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WebDAQ 316 User’s Guide
8

TC6[+]

Channel 6 HI

36

TC6[–]

Channel 6 LO

9TC7[+]

Channel 7 HI

37

TC7[–]

Channel 7 LO

10TC8[+]

Channel 8 HI

38

TC8[–]

Channel 8 LO

11TC9[+]

Channel 9 HI

39

TC9[–]

Channel 9 LO

12TC10[+]

Channel 10 HI

40

TC10[–]

Channel 10 LO

13

TC11[+]

Channel 11 HI

41

TC11[–]

Channel 11 LO

14

TC12[+]

Channel 12 HI

42

TC12[–]

Channel 12 LO

15

TC13[+]

Channel 13 HI

43

TC13[–]

Channel 13 LO

16

TC14[+]

Channel 14 HI

44

TC14[–]

Channel 14 LO

17

TC15[+]

Channel 15 HI

45

TC15[–]

Channel 15 LO

18

COM

Common46

COM

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