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AT1616L: RS485/RS232 Digital I/O Board with On-Board WAGO Terminal Strips


"Let me spin a very large
RS485 network for you!"

  • This unit interfaces 16 opto-isolated inputs and 16 form C relay outputs to a host computer through a bi-directional serial port at jumper selectable data rates up to 115.2 Kbps.

  • The addressable bi-directional RS485(2 wire) port provides multi-drop capability at the device count and distance limitations of the RS485 EIA/TIA specification. Typically: 32 standard loads at 4000 ft.

  • The addressable bi-directional RS232 port provides point to point communications at the distance limitations of the RS232 EIA/TIA specification.

  • The 16 opto-isolated inputs can be jumper configured to be driven by contact closure with a common connection and the excitation voltage provided by the board.

  • The 16 opto-isolated inputs can also be jumper configured as floating inputs driven by an external signal of 5 to 27 VDC at 1.2 to 9 mA.

  • The 16 form C relay contacts are rated at 1 amp at 30VDC.

  • The onboard firmware accomodates a wide variety of operational modes. A new, compact, fast command structure enhances the user interface. The classic command structure has been preserved for compatibility with older systems.

  • The extensive flexible command structure is fully explained on the RS485.com web site

  • When factory configured in "Stand Alone" mode, two units serve as a I/O extension pair through a serial link. The inputs on one board energize the corresponding relays on the other board

  • LEDs provide visual indication of input , output, data activity, and power level.

  • A polarity protected efficient switching power regulator accepts supply voltages from 9 to 35 VDC (2 Watts max.)

  • User connections are spring loaded "Wago" style terminal strips for I/O, the RS485 interface, and supply power. An RJ11/12 telephone style connector is used for the RS232 interface.

  • Broad environmental range. Temperature: -40C to +85C (-40F to +185F). Humidity: 10 to 90% RH (non-condensing)

  • Six(6) easy mount through hole standoffs, which accept #6 hardware, are provided on the circuit board.

  • Accessories available are a 12VDC Switching Power Supply (Wall Wart), and a 7ft DB9F to RJ11/12 RS232 cable.

  • We strongly recommend that a first time user of this product purchase the optional DB9F to RJ11/12 RS232 cable.

  • The limitations of the RS232 communications method can be solved by the wide variety of R E Smith devices. Our converters, buffers, isolated converters, and addressable converters mitigate the distance limitations and electrical noise problems that contribute to unreliable communications and product failure.

  • Conformal Coating, other cables, and other connectors are factory options. If what you see here is not exactly what you need, don't hesitate in calling us at (513) 874-4796

General Description:

This board is used worldwide for gathering digital input data and controlling external devices through the 16 isolated inputs and the 16 form C independent relays. In addition to the commands for reading and writing the I/O points, there are a set of commands, which enable the user to check the I/O status, unit type, unit address, configuration, software version, and jumper settings.
The new command structure maximizes the data flow to and from the board. The classic command structure has been preserved to maintain compatibility with our earlier installed base of units. The choice of command structures is selected by a single jumper, J19. When the configuration jumpers are changed, the power to the board must be cycled to make the changes effective.

RS485/RS232 Digital I/O Board with 16 Opto-Isolated "Wetted" or "Dry" Inputs, 16 Form-C Relay Outputs, with On-Board WAGO Terminal Strips (12VDC operation only.)

The AT1616L Remote I/O Board has 16 opto-isolated inputs and 16-Relay (Form C) outputs. The unit can be controlled by our simple/efficient command structure from a host computer (computer mode), such as a PC. The unit can communicate using RS485 or RS232, at data rates up to 115.2Kbps bits/second. Up to 256 units (in computer mode & with repeaters) can be connected on a single pair of wires to form a large (4096 I/O points) RS485 multi-drop network. The AT1616L has an onboard switching regulator for 12VDC operation, LED indicators for all inputs and outputs, 18 jumpers for communications address, Baud rate, mode control, etc. Wago terminal connectors (spring loaded) are provided for ease of installation/removal. The RS485 serial port has built in transient protection and jumper selectable termination. LED indicators monitor the data flow of the serial port. "Less is more" when using our command structure to control the AT1616L. Only three ASCII commands are needed for full control: 1) The "LXX" command addresses the unit and returns the unit address and the input status of IL7 thru IL0; 2) The "K?DD" command can be used to control any one of the sixteen individual relay (K1 - K8, with or without an 8-bit timer), or the on/off status of all 8 relays, can be updated with a single execution of this one command. Other commands are available to check current I/O status, jumper settings (J8-J24), unit type, and software version. A terminal emulator and a few minutes are all that is necessary to learn our command structure. Quick basic software with source code is also provided to monitor/control the unit. The simplicity of the command structure allows for fast control in large multi-drop networks (less than 20mSec/unit at 9600,n,8,1 and only about 2mSec/unit at 115.2Kbps,n,8,1). Delays are NOT required and bandwidth utilization is at a maximum. All commands and hex data are in capital letters. The range 0-9 and A-F are reserved for data. The letters G through Z are available for commands. Command strings are generally 1 to 4 characters in length. Return strings from the AT1616L are generally 4 characters long; however, larger strings (up to 18+ characters) are possible in our "Classic" command mode. The "Classic" command mode is supported to allow for backward compatibility in existing systems. Also in the future, two units can be operated in a standalone mode (master/slave mode) to form a "Relay extension cord," with 16-channels of control in each direction, at distances of up to 4000 ft. or more (order AT1616L-SAL for special software).

Need something special? Please contact us. We have additional isolated and non-isolated converters, repeaters, and repeater hubs. Units are generally stock to 2-3 business days for shipment. We design and manufacturer our entire product line, and offer technical support for our units, and can offer system recommendations for your application. Please give us a call: 513-874-4796

Related Files:

pdf icon AT1616L.pdf Schematic - CPU
pdf icon AT1616I.pdf Schematic - Inputs
pdf icon AT1616O.pdf Schematic - Outputs
pdf icon AT1616SS.pdf Physical
pdf icon AT1616L Manual.pdf Operating Manual

Physical Properties and Features:

Additional information coming soon!


Additional information coming soon!

Options and Ordering Information:

Additional information coming soon!

Need a different configuration or more information? Give Ron a Call at 513-874-4796 or 513-638-0228(Cell)


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