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

Features

• 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

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  

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  

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.

Specifications