Diamond Systems Diamond-MM-48-AT

Introduction

Diamond-MM-48-AT is the newest in Diamond Systems' popular AT series of PC/104 autocalibrating analog I/O boards. It combines the features of two different I/O boards into a single board to reduce the size and weight of your PC/104 stack.

The analog I/O features are similar to our DMM-16-AT board: 16 analog inputs with 16-bit A/D, 8 analog outputs with 12-bit D/A, and on-board counter/timer for A/D sample rate and interrupt control.

The digital I/O features are similar to our Opal-MM board: 8 relays with SPDT (form C) contacts and 4 optocouplers with up to 28V AC/DC input capability. The optocouplers feature an interrupt on edge detection feature for safety applications. An additional 4 TTL level digital I/O lines are also provided on the board, and these lines also feature interrupt on edge detection capability.

Diamond-MM-48-AT is designed for rugged environments. It uses latching I/O connectors, and all jumpers can be bypassed with the installation of 0-ohm resistors to provide a vibration-proof fixed configuration. In addition the board is tested and guaranteed to operate reliably over the industrial temperature range of -40 to +85°C.

Analog I/O Features

The analog input circuit features 16 A/D input channels with 16-bit resolution, single-ended configuration, and a fixed input range of +/-10V (0-10V and +/-5V are also available as factory settings). The maximum sampling rate is increased to 200KHz and is supported by a new larger 2K sample FIFO. The analog output circuit has 8 D/A channels with 12-bit resolution and a 0-4.096V output range. This range provides an intuitive conversion formula of 1mV per LSB to simplify programming and provide a more appropriate set of true output voltages.

Automatic Calibration

Diamond-MM-48-AT features Diamond Systems' advanced autocalibration technology. This feature provides maximum accuracy of your analog measurements over temperature and time. A set of precision references on the board with known values is used to calibrate the A/D circuit offset and gain. These references are sampled and compared to their known values which are stored in an on-board EEPROM. A built-in adjustment circuit modifies the response of the A/D circuit to bring the reference measurements to within 2LSB (typically 1LSB or better) of their correct values. The adjustment values are also stored in the EEPROM, and each time the board powers up these values are automatically recalled and used to program the input circuit. The entire procedure is controlled by our Universal Driver software. It takes approximately one second and can be run at any time, for example each time the system powers up or once a day.

A/D sampling rate control

A/D samples may be triggered in three different ways: software command, on-board counter/timer, or external trigger. The on-board counter/timer circuit consists of a 24-bit programmable counter/timer with a user-selectable input clock of 10MHz or 1MHz. This supports sampling rates from the maximum 200KHz down to a minimum rate of .06Hz. The A/D trigger signal can initiate a single A/D conversion or a “scan” of any number of channels. Each A/D value is stored in the on-board FIFO. At the end of the conversion or scan, the data may be read out from the FIFO immediately, or the FIFO can continue to fill up with additional samples or scans until its selected threshold is reached. When the threshold is reached, an interrupt may be generated, and the interrupt routine (built into our Universal Driver software) will empty the FIFO and transfer the data to the user program. DMM-48-AT features a programmable FIFO threshold of 1/8 full (256 samples) or 1/2 full (1024 samples).

Digital I/O features

Diamond-MM-48-AT includes 8 relays with SPDT (form C) contacts. These contacts feature both a normally-open and a normally-closed contact for increased functionality. Capacity is 1A / 30VDC.

The four optocoupler inputs feature 3-28V AC / DC input (non-polarized) and programmable edge detection. Each input can be independently programmed for positive or negative edge trigger. When any selected edge event occurs, an interrupt will be generated and control will be passed to your own custom code.

In addition, the board has 4 TTL level digital I/O lines with individually programmable direction (any combination of inputs and outputs) and edge detection. When edge detection is enabled on these lines, any change of state will generate an interrupt that will then run your own custom code.

Counter/Timer features

In addition to the A/D sample-rate counter mentioned above, the board includes a second 16-bit counter that is fully user programmable. It has a selectable input clock of 10MHz or 100KHz, and the output can be used to drive external circuitry or to generate an interrupt to run your own code at programmed intervals.

Analog Circuit

I/O Headers

Diamond-MM-48-AT has two latching I/O headers: one for analog I/O + TTL digital I/O, and one for the relays and optocouplers.

Software

The industry-leading Universal Driver software is available free with all Diamond Systems I/O boards. Universal Driver provides programming support for the most popular embedded operating systems, including Linux, Windows 95/98/NT/2000/XP/XP embedded, Windows CE.NET, QNX, VxWorks, and DOS. Example programs are provided for each function and each operating system to help you get started with your application development quickly.