WebDAQ 904
Internet Enabled Universal Input Logger

Remote Configuration and Monitoring

Virtually Unlimited Storage

Integrated HW and SW

Flexible Triggers,
Alarms, Events,
Email and SMS Text
Notification
Built-in Web Server,
Easy-to-Use

Multiple input modes:- Voltage- Current- RTD- Thermocouple- Resistance- Bridge-based sensor

WebDAQ 904
Internet Enabled Universal Input Logger
Features• Four 24-bit simultaneous
analog inputs; individuallyconfigurable:− Voltage (up to ±60 V),
current, RTD, thermocouples,
resistance, bridge-based
sensors
The WebDAQ 904 intelligent logger features universal inputs and remote monitoring andcontrol of real-time data.

Overview
The WebDAQ 904 is a stand-alone universal input logger designed for remotemonitoring and control. All the intelligence is built into the WebDAQ, eliminating
the need for a PC or additional software. By using the embedded WebDAQ web
server, users can easily configure simple or sophisticated applications, log sensor
data, update digital outputs and/or send notifications based on alarm conditions,and view real-time data from any location and any device with a web browser.
The WebDAQ 904 performs high-accuracy measurements from up to four analog
inputs. Users can measure several signals from sensors such as strain gauges, RTDs,
thermocouples, and load cells. Housed in a heavy-duty chassis, the WebDAQ 904
is rugged enough for industrial applications.

Integrated Software andHardware
The WebDAQ Series embedded OS andweb server provides an all-in-one package
for stand-alone data logging and alarming. Users can monitor and control theirapplications from anywhere with a web
browser.
The WebDAQ web server is optimized
for both desktop and mobile use. Users
can perform data acquisition tasks fromphones, tablets and laptops with a single,
intuitive user interface.

• 100 S/s/ch sample rate, max• Voltage and current excitation• Four isolated DIO for triggers
and alarms• Log data to internal storage ormapped network storage• Share folders to view files overa local network• Export data to csv, UFF,
or binary for use in otherapplications• Alarm and event notifications
with email and SMS messaging

Remote Access and Control• Easy, flexible task scheduling

Install the WebDAQ 904 on any network
and access it using any device with a web
browser to remotely monitor and control
all operations.

• Configurable read/write accessWireless communication• No driver software to install• Built-in web server• Remote monitoring and control

After the WebDAQ is detected on a wired
network , users can connect an approved
WiFi adapter to the rear panel and communicate with the WebDAQ over a wirelessnetwork. Refer to our website for a list of
the WiFi adapters approved for use with
WebDAQ Series hardware.

• WiFi support

Flexible Triggering
Start or stop the acquisition based on
analog or digital thresholds, alarm states,or date/time values. On-demand pushbutton triggering is also supported.

WebDAQ Web Interface
An embedded web server provides a clean,intuitive interface to access all configuration and data management tasks.
Hardware, trigger and alarm settings arecontained in a single task, or “job”. Multiple “jobs” can be run in a “schedule” formore complex data logging applications.
For example, users can create a scheduleof jobs in which one job automaticallyruns after an alarm condition is triggeredon a different job, such as when a digital
input changes.

Measurement Computing

Device-independent operation lets you remotely monitor and control the WebDAQ 904 fromany device with a web browser.

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WebDAQ 904
Introduction
Easy Setup – Powerful Capabilities
Jobs are the building block of WebDAQ. The ability to define different data logging jobs, or tasks, and add them to a schedule
unleashes flexibility not seen in any other data logger.
Whether you want to set up a simple logging task or a complex task, jobs and a schedule make it easy and straightforward.

What is a Job?

What is a Schedule?

The basic building block of WebDAQ, a job defines channel
configuration, logging options, start and stop conditions, andalarming.

A schedule is a collection of jobs that gives flexibility to dynamically change data logging attributes, such as sampling rate, active
channels configuration, or alarm levels.

Example:Switching from static acquisition to dynamic
acquisition.
1 Schedule and 2 Jobs
Users can easily setup a job for a slow,
static acquisition and a fast dynamic
acquisition. When a trigger condition
is met (such as over/under alarm),
Job 1 (slow acquisition) ends and Job 2(fast acquisition) begins. When the trigger
condition returns to normal, Job 1 can berestarted.

Clear, Concise, Data Displays
WebDAQ users don’t need to rely on the small
screens and difficult to navigate displays of mostother loggers. With WebDAQ’s intuitive webinterface, users can easily see their data and alarm
conditions in real time or after the acquisition iscomplete.

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WebDAQ 904
Features
Alarm and Event Notifications

Universal Input Modes

Create multiple alarms using analog or digital channel sources.
Configure alarms to reset and re-arm when the condition clears,
or reset them remotely with your browser. View the alarm statuson the web interface.

Each channel is configurable for a different input mode:•

Voltage•

Current

Users can configure one or more events to record when a job isstarted, stopped, or triggered, or if an error condition is detected.

•

Thermocouples•

RTD (4-wire and 3-wire)

Receive alarm and event notifications on one or more addresses
using email and SMS messaging.

•Resistance (4-wire and 2-wire)•

Bridge-based sensors (half- and full-bridge, and other powered load cells)

Virtually Unlimited Storage

Measurement ranges vary for each type of measurement; referto the Specifications section for range values per input mode.
The max sample rate is 100 S/s per channel.

Store data files and configuration settings locally in internal flash
memory, or save to external media or network folders.
Users can map a network drive or FTP server as the location tolog data or store files.

Voltage and current excitation is provided for applicable input
modes. Each channel has a built-in thermistor for cold-junction
compensation (CJC) calculations when measuring thermocouples. An analog pre-filter removes noise that may be present in
the signals prior to conversion.

Easily transfer files between WebDAQ storage locations andmapped network storage locations.

Share Folders

Timing Modes

Users can share a WebDAQ storage location or specific folder
over a local network.

The WebDAQ 904 supports high resolution, 50 Hz rejection,
60 Hz rejection, and high speed timing modes.

Real-Time Data Display•

View data as it is acquired or from a stored file. Users can specify
a range of data to view and zoom in or out. Data is plotted on
strip chart and scalar displays.

High resolution mode optimizes maximum overall noise
rejection and provides rejection of 50 Hz and 60 Hz noise•

50 Hz rejection mode optimizes 50 Hz noise rejection•

60 Hz rejection mode optimizes 60 Hz noise rejection

Control Read and Write Access•High speed timing mode optimizes the sample rate

Users can control who can view and modify job settings bydefining a password and setting the security level.

Isolated Digital I/O

Run the Schedule on Startup

The four isolated digital I/O lines can be used either as triggers
to start or stop the acquisition or as alarm outputs.

Automatically run the schedule when the system starts up or
at a specified date and time. Multiple jobs in the schedule are
run consecutively.

Flexible Power Requirements
Provide power with the 9 volt, 1.67 amp supply that ships withthe device, or connect any 6 to 16 DC supply.

Real-Time Clock

Firmware Updates

A real-time clock provides an absolute time reference for timestamping data. The clock can be set to any timezone, and may
be synchronized to the internet time server.

Device firmware is bundled with the operating system andweb server in one update file. This allows the WebDAQ to be
updated in the field.

Analog Input

Calibration

The WebDAQ 904 provides four individually configurable channels of 24-bit universal analog input.

The WebDAQ is factory-calibrated using a NIST-traceable calibration process. Specifications are guaranteed for one year. Returnthe device to the factory for recalibration.

All channels are measured simultaneously at rates of up to
20 ms (high speed mode) or 510 ms (high resolution mode).
Refer to the Specifications section for the conversion times for
all timing modes.

REST API
The WebDAQ REST API allows users to communicate with thedevice outside of the web interface to retrieve information about
the system, schedules, and jobs, get acquisition and alarm status,
and to start/stop an acquisition.

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WebDAQ 904
Functional Block Diagram

Real-time
Clock withBattery

Spring Terminals

Screw Terminals

Buttons/
LEDs

4

4

Isolated
DIO

Universal Input
Measurement
ModuleMicroprocessor,
RAM, and FlashSD
Connector

Raspberry Pi
ComputeModuleUSB Hub
and10/100 Ethernet
Controller

Dual USB
Connectors

RJ-45
Ethernet
Connector

Power
Supplies

Power
Input
Ext Pwr+9 VDC/1.67 A

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WebDAQ 904
Front and Rear Panels
Front Panel
Detachable spring and screw terminals allow quick analog and digital connections.

Rear Panel
The rear panel provides Ethernet and power connections, LED indicators, dual USB ports, one SD card slot, buttons, and a groundconnector.

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WebDAQ 904
Specifications
All specifications are subject to change without notice.
Typical for 0 °C to 50 °C unless otherwise specified.

Accuracy
Mode, range

Analog Input

Number of channels: 4 analog input channels
ADC resolution: 24-bit
Type of ADC: Delta-Sigma (with analog prefiltering)
Sampling mode: Simultaneous
Input modes: Voltage, Current, Resistance (4-wire and 2-wire), RTD (3-wire and4-wire), Thermocouple, Quarter-bridge, Half-bridge, Full-bridge
Conversion time, no channels in TC mode
High speed: 10 ms for all channels
Best 60 Hz rejection: 110 ms for all channels
Best 50 Hz rejection: 130 ms for all channels
High resolution: 500 ms for all channels
Conversion time, one or more channels in TC mode
High speed: 20 ms for all channels
Best 60 Hz rejection: 120 ms for all channels
Best 50 Hz rejection: 140 ms for all channels
High resolution: 510 ms for all channels
Overvoltage protection: terminals 3 through 6, across any combination: ±60 V
Input impedance
Voltage mode (±60 V, ±15 V, ±4 V): 1 MΩ
Current mode: <40 Ω
All other modes: 1 GΩ
Input bias current: <1 nA
Integral non-linearity (INL): ±15 ppm
Common mode rejection ratio (CMRR)
fin = 60 Hz: >100 dB
Normal mode rejection ratio (NMRR)Best 60 Hz rejection: 90 dB at 60 Hz
Best 50 Hz rejection: 80 dB at 50 Hz
High resolution: 65 dB at 50 Hz and 60 Hz

Offset error(ppm of range)

Typical 25 ºC, ±5 ºC,–40 to 70 ºC max
Voltage, ±60 V±0.3, ±0.4±20, ±50

Voltage, ±15 V±0.3, ±0.4±60, ±180

Voltage, ±4 V

±0.3, ±0.4±240, ±720

Voltage, ±1 V

±0.1, ±0.18±15, ±45

Voltage/Thermocouple, ±125 mV±0.1, ±0.18±120, ±360

Current, ±25 mA±0.1, ±0.6±30, ±100

4-wire and 2-wire resistance, 10 kΩ *±0.1, ±0.5±120, ±320

4-wire and 2-wire resistance, 1 kΩ *±0.1, ±0.5±1200, ±3200

4-wire and 3-wire RTD, Pt 1000

±0.1, ±0.5±240, ±640

4-wire and 3-wire RTD, Pt 100±0.1, ±0.5±2400, ±6400

Quarter-bridge, 350 Ω±0.1, ±0.5±2400, ±6400

Quarter-bridge, 120 Ω±0.1, ±0.5±2400, ±6400

Half-bridge, ±500 mV/V

±0.03, ±0.07±300, ±450

Full-bridge, ±62.5 mV/V

±0.03, ±0.08±300, ±1000

Full-bridge, ±7.8 mV/V

±0.03, ±0.08±2200, ±8000

CJC sensor accuracy±1 ºC, typical* 2-wire resistance mode accuracy depends on the lead wire resistance. This table
assumes 0 Ω of lead wire resistance.

Input mode ranges
Input mode

Gain error(% of reading)

Nominal range(s)Actual range(s)Voltage±60 V, ±15 V, ±4 V, ±1 V,±125 mV±60 V, ±15 V, ±4 V, ±1 V,±125 mV

Current±25 mA±25 mA

Thermocouple±125 mV±125 mV

Voltage, ±60 V

±20

±0.2

4-wire and 2-wire resistance

10 kΩ, 1 kΩ

10.5 kΩ, 1.05 kΩ

Voltage, ±15 V

±20

±0.8

4-wire and 3-wire RTD

Pt 1000, Pt 100

5.05 kΩ, 505 Ω

Voltage, ±4 V

±20

±3.2

Quarter-bridge

350 Ω, 120 Ω

390 Ω, 150 Ω

Voltage, ±1 V

±10

±0.2

Half-bridge±500 mV/V±500 mV/V

Voltage/thermocouple, ±125 mV

±10

±1.6

Full-bridge±62.5 mV/V, ±7.8 mV/V

±62.5 mV/V, ±7.8125 mV/V

Current, ±25 mA

±15

±0.4

4-wire and 2-wire resistance, 10 kΩ

±15

±3

4-wire and 2-wire resistance, 1 kΩ

±15

±30

4-wire and 3-wire RTD, Pt 1000

±15

±6

4-wire and 3-wire RTD, Pt 100

±15

±60

Quarter-bridge, 350 Ω

±15

±120

Quarter-bridge, 120 Ω

±15

±240

Half-bridge, ±500 mV/V

±3

±20

Full-bridge, ±62.5 mV/V

±3

±20

Full-bridge, ±7.8 mV/V

±3

±20

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Stability
Mode, range

7

Gain drift(ppm of reading/ºC)

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Offset drift(ppm ofreading/ºC)

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WebDAQ 904
Specifications
Network

Input noiseMode, range

Ethernet type: 100 Base-TX, 10 Base-T
Communication rates: 10/100 Mbps, auto-negotiatedConnector: RJ-45, 8 position
Cable length: 3 meters (9.84 feet) max
Additional parameters: HP Auto-MDIX support

Conversion time
High
speed

Best 60
Hz rej.

Best 50
Hz rej.

High
resolution

Voltage, ±60 V

7.6

1.3

1.3

0.5

Voltage, ±15 V

10.8

1.9

1.9

0.7

Voltage, ±4 V

10.8

2.7

2.7

1.3

Voltage, ±1 V

7.6

1.3

1.3

0.5

Voltage/thermocouple, ±125 mV

10.8

1.9

1.9

1.0

Current, ±25 mA

10.8

1.9

1.9

1.0

4-wire and 2-wire resistance, 10 kΩ

4.1

1.3

0.8

0.3

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 name may be changed using the web interface.
Network name publication: By mDNS
User accounts: admin and share. These accounts are case-sensitive and cannot bechanged using the web interface.

4-wire and 2-wire resistance, 1 kΩ

7.1

1.8

1.2

0.7

Factory default settings

4-wire and 3-wire RTD, Pt 1000

7.6

1.7

1.1

0.4

4-wire and 3-wire RTD, Pt 100

10.8

1.9

1.9

0.9

Quarter-bridge, 350 Ω

5.4

1.0

1.0

0.7

Quarter-bridge, 120 Ω

5.4

1.0

1.0

0.7

Half-bridge, ±500 mV/V

3.8

0.5

0.5

0.2

Full-bridge, ±62.5 mV/V

5.4

1.0

1.0

0.8

Full-bridge, ±7.8 mV/V

30

4.7

4.7

2.3

Measurement
conditions

Load resistance (Ω)

Network configuration

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 for admin account: admin. Passwords are case sensitiveand can be changed using the web interface.
Factory default password for share account: share. Passwords are case sensitive andcan be changed using the web interface.
Factory default device name: webdaq-xxxxxx, where xxxxxx is the last 6 digits of
the MAC address (printed on the label on the underside of the device).
Note: When factory defaults are restored, any shared folders or mapped drives
are reset.

USB ports

Excitation level

Half-bridge

Full-bridge

700

2.5

Number of USB ports: Two, for connection to a mass storage device or approved
WiFi adapter.
USB device type: USB 2.0 (high-speed)Device compatibility: USB 1.1, USB 2.0, USB 3.0

240

2.0

SD memory card slot

350

2.7

120

2.2

Excitation (V)Memory card type: SD, SDHC, SDXC, MMC, TransFlash
File systems supported: FAT16, FAT32, exFAT, ext2/3/4, NTFS

Push buttons

Power (POWER):
W1 jumper installed (factory default): Turns device on or off.
W1 jumper removed (device on when power is applied): Reboots the device.
Function (FUNC): Unmounts external media, or starts/stops an acquisition
Reset (CONFIG RESET): Restores network and alarm settings to factory default values.

Resistance, RTD, and quarter-bridge mode excitation level
Load resistance (Ω)

Excitation (V)

120

50

350

150

1,000

430

Connector port for the #6-32 ground screw.

10,000

2,200

Power

Ground connector

Input voltage: Center positive. 6 VDC to 16 VDC
Input wattage: 4 W typ, 10 W max
External AC adapter: 9 VDC, 1.67 amps, 110 VAC to 240 VAC input range
Battery: One 3 V button cell lithium battery required to maintain time of day
clock when device is powered off. Replace with Panasonic BR-1225 3V lithiumcoin cell battery or equivalent. See user’s guide for the replacement procedure.
Note: refer to the user’s guide for behavior when jumper W1 is installed or removed.

Digital input/output

Digital type: CMOS (Schmitt trigger) input / open drain output
Number of I/O: One port of 4 bits
Configuration: Bit configurable 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
Input frequency range: DC – 10 kHz. Applying a signal with a higher frequency
will adversely affect system performance and could cause errors.
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 absolute 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 max**
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** The external pull-up resistor is connected between the digital output bit andexternal 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.

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Shock

Operating shock: 30 g, 11 ms half sine; 18 shocks at 6 orientations

Mechanical

Dimensions (L × W × H): 158.8 × 146.1 × 38.1 mm (6.25 × 5.75 × 1.50 in.)With BNC connectors: 178.8 × 146.1 × 38.1 mm (7.04 × 5.75 × 1.50 in.)
Weight: 680 g (1.5 lb)

Environmental

Temperature range: 0 °C to 50 °C max (Operating), –40 °C to 85 °C (Storage)
Ingress protection: IP 30
Humidity: 10- 90% RH, noncondensing (Operating), 5-95% RH (Storage)
Maximum altitude: 2,000 m (6,562 ft)
Pollution degree: 2
The WebDAQ 904 is intended for indoor use only.

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WebDAQ 904
Ordering
Order Information

Accessories

HardwarePart No.

Description

ACC-205

DIN-rail mounting kit; requires the ACC-404 panel/wall mounting kit.

ACC-403

6-position detachable screw terminal (2).

ACC-404

Panel/wall mounting bracket; use with the ACC-205
to mount on a DIN rail.

ACC-405

6-position detachable spring terminal (4).

PS-9V1AEPS230V

9 VDC, 1.67 A replacement power supply.
Interchangeable power plugs are available separately.

745690-E001

E-type thermocouples wire, fiberglass(0 °C to 482 °C, 32 °F to 900 °F), 1 m

745690-E002

E-type thermocouples wire, fiberglass(0 °C to 482 °C, 32 °F to 900 °F), 2 m

745690-J001

J-type thermocouples wire, fiberglass(0 °C to 482 °C, 32 °F to 900 °F), 1 m

745690-J002

J-type thermocouples wire, fiberglass(0 °C to 482 °C, 32 °F to 900 °F), 2 m

745690-K001

K-type thermocouples wire, fiberglass(0 °C to 482 °C , 32 °F to 900 °F), 1 m

745690-K002

K-type thermocouples wire, fiberglass(0 °C to 482 °C, 32 °F to 900 °F), 2 m

745690-T001

T-type thermocouples wire, fiberglass(0 °C to 482 °C, 32 °F to 900 °F), 1 m

745690-T002

T-type thermocouples wire, fiberglass(0 °C to 482 °C, 32 °F to 900 °F), 2 m

745691-01

3-wire, 100 Ω RTD, sealed with alumina tube, 1 m

745691-02

3-wire, 100 Ω RTD, platinum (ready made), 2 m

Part No.

Description

WebDAQ 904

Internet enabled universal input logger with four analog
inputs, simultaneous sampling, support for multiple
measurement types, embedded operating system and web
server; includes the PS-9V1AEPS230V power supply with
USA, UK, and Europe plugs.

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