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SENSORAY Model 2426 Multifunction analog/digital I/O with serial COM

SENSORAY Model 2426 Multifunction analog/digital I/O with serial COM


  • Controls/monitors real world signals over Ethernet
  • 8 isolated digital inputs w/debounce
  • 16 digital outputs w/PWM mode & integrated support for safety interlocks
  • Six 12-bit analog inputs
  • One 12-bit analog output
  • RS-422/RS-485 async serial port
  • 1 incremental encoder interface
  • Embedded HTTP and Telnet servers
  • Open source API
  • Low cost, low power & compact size
  • DIN-3 rail mountable

Model 2426 is a versatile open-frame module that interfaces a variety of real world signals to a 10/100 Mbps Ethernet. It has eight optically isolated digital inputs, 16 digital outputs, six 12-bit analog inputs, one 12-bit analog output, an asynchronous serial port with RS-422/RS-485 phy, and a high speed incremental encoder interface, all powered by an external 24 VDC supply (not included). The module's compact footprint allows it to fit into tight spaces, and the built-in DIN rail mounting hardware makes installation quick and easy.

2426 Block Diagram

SENSORAY Model2426 blockdiagram

Network Servers

Remote network clients communicate with the module via its built-in servers (telnet for manual and automated control; HTTP for configuration, manual control, and diagnostics), which allows any web browser or telnet client to remotely monitor and control I/O without any special device drivers or proprietary software. In the case of telnet, commands and replies are conveyed in plaintext, which can dramatically reduce development time and simplify maintenance.

2426 Control page screenshot  

SENSORAY Model 2426 screenshot

Software development kit

A free software development kit is available for model 2426 which includes documentation, sample applications and a comprehensive application program interface (API). Pre-built API libraries are included for Linux and Windows, along with API source code (C language) and instructions for OEM customization and porting.

The API transparently handles all of the underlying telnet and module command protocols so that programmers can focus on application development. For example, application software can simply call the s2426_WriteDout() function to program the general purpose digital outputs.

Concurrent access

The module supports simultaneous communication with multiple clients. For example, maintenance personnel can plug into the network and monitor the module while, at the same time, the module is controlled by an automation process running on another computer.

Furthermore, the API allows any process to utilize multiple concurrent sessions. A typical application of this is to have one thread handle RS-422/RS-485 serial communication while another thread interacts with I/O interfaces on a separate session, resulting in straightforward application code that tends to be robust and easily maintained.

Watchdog timers

A hardware watchdog timer will reset the module in the event of an internal module malfunction. In addition, a communication watchdog will trigger a module reset if a client fails to communicate with the module in a timely manner. In both cases, the reset will automatically force all outputs to "safe" states.

Support for safety interlocks

Each digital output can be configured to unconditionally deactivate its output driver when an associated contact (e.g., safety interlock, emergency stop switch) is open. Implementing this commonly required feature in the module allows external termination boards to be eliminated and wiring to be simplified, with a commensurate reduction in system complexity and cost.

Digital output channel block diagram  

SENSORAY Model2426 Digital output channel block diagram

Typical interlock application

SENSORAY Model2426 Typical interlock application

2426TA Termination Board

An optional breakout termination board, model 2426TA, is available for the 2426. It plugs directly onto the 2426 with board-to-board interconnects so that minimal overhead space is used and no cables are needed. Field wiring can then be quickly and easily inserted into the 2426TA's spring terminal blocks.

SENSORAY Model 2426TA termination board

Communication Interfaces
Network Physical layer 10BaseT, 100BaseTx Ethernet
Bit rate 10/100 Mbps, auto-detecting
Isolation 1500Vrms
Configuration Programmable via HTTP (static ARP): IP address, netmask, gateway
HTTP Server Concurrent sessions 0 to 1
Functions Status, configuration, I/O monitor/control
TELNET Server Concurrent sessions 0 to 3
Time-out interval 5 minutes (default, reprogrammable via HTTP), programmable per session via shell
Async Serial COM Physical layer RS-422 or RS-485, shunt configurable
Bit rate 300 bps to 115.2 Kbps, software selectable
Termination (RS-422/485) 120 ohms ±5%, transmit and/or receive pair, enabled via shunts
Receiver turnaround 250 µs maximum
Telnet protocol options Com Port Control (RFC 2217), Binary Transmission (RFC 856)
Timestamp Generator Count rate 1.0 MHz
Resolution 32 bits, 1.0 µs
Analog Interfaces
Analog Inputs Channels 6 external, 2 internal reference
Resolution 12 bits
Input type Differential
Differential input range -10V to +10V, minimum (at 0V CMV)
CMV input range -10V to +10V
Input impedance 22M ohms minimum
Conversion rate 1000 samples/s per channel
Inter-channel acquisition skew 125 µs maximum
Trigger Internal hardware timer
Data format Signed 16-bit integer with timestamp
Analog Output Resolution 12 bits
Output range -10V to +10V, minimum
Settling time 500 µs maximum (20V step change)
Data format Signed 16-bit integer
Encoder Interface
Encoder Interface Resolution 32 bits
Count rate 0 to 30 MHz
Clock rate 0 to 7.5 MHz
Clock/Index input signals RS-422 differential, TTL/5VCMOS compatible, ±7V CMV maximum
Encoder power output 5VDC ±5%, 100mA maximum
Data format Signed 32-bit integer with timestamp
Digital Interfaces
Digital Inputs Channels 8
Input type Differential pair, optically isolated with 4.7 Kohm series impedance
Input range +5V to +24V
Digital Outputs Channels 16
Output type Active low, open collector drive with inductive load EMF suppression diode
Output high-level voltage source Internal, shunt selectable from continuous 24V or any interlock power source
Output current 100 mA maximum per channel, 500 mA maximum total
Power and Environmental
Module Power Input power 24VDC ±5% @120mA (digital outputs off, no external loads)
Interlock Power Channels 5
Voltage range +5VDC to +24VDC, referenced to module input power
Current 500mA maximum, per circuit
Temperature Operating range -25 to 85 °C
Module Dimensions Outer dimensions (W x H x D): 5.3 x 5.0 x 2.2 inches
W = DIN rail length
D = module height from DIN rail back panel; additional clearance required for field wiring.
Mating Connectors
(*) = included with module
Ethernet RJ-45 plug, AMP 554169 or equivalent
Terminal block (*) Pluggable TB, Phoenix Contact or equivalent
Serial COM DB-9 male, Norcomp 171-009-102-001 or equivalent
Encoder DB-9 female, Norcomp 171-009-202-001 or equivalent
Analog I/O DB-25 female, Norcomp 171-025-202-001 or equivalent
Digital inputs DB-37 female, Norcomp 171-037-202-001 or equivalent
Digital outputs DB-37 male, Norcomp 171-037-102-001 or equivalent
Feel free to request a quote