Measurement Specialties PCI-DIO24 manual Functional Details, DIO signals, Signal level control

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Chapter 4

Functional Details

DIO signals

All digital outputs and inputs on the PCI-DIO24 are CMOS TTL. Voltages and currents associated with external devices are usually far greater than can be supplied from a PCI-DIO24.

Caution! Direct connections to high-current/high voltage devices will damage the board.

The 82C55 digital I/O chip initializes all ports as inputs on power-up and reset. The state of the digital I/O lines is not defined as either logic high or logic low when in input mode. Input devices connected to the PCI-DIO24 board may detect either a high or a low, and therefore may be turned off or on at power-up.

Signal level control

All I/O bits are set to a high impedance input mode on power up and reset. To prevent unwanted signal levels, and to drive all inputs on the device you are controlling to a known state after power up or reset, install pull-up or pull-down resistors.

A pull-up resistor pulls all digital pins up to +5 V (high logic level). A pull-down resistor pulls all digital pins down to 0 V (low logic level).

The PCI-DIO24 has open locations where you can install a 2.2 KΩ, eight-resistor single inline package (SIP) resistor network for each port. The SIP is made up of eight 2.2 KΩ resistors. One side of each resistor is connected to a single common point and brought out to a pin. The common line is marked with a dot or line at one end of the SIP. The remaining resistor ends are brought out to the other eight pins (see Figure 4-1).

2.2KOhm SIP

Dot

(LO or HI)

I/O Lines

Figure 4-1. Eight-resistor SIP schematic

Install the SIP on the PCI-DIO24 board at the locations labeled PORT A, PORT B and PORT C (adjacent to the 37-pin connector). Figure 4-2shows a schematic of an SIP installed in both the pull-up and pull-down positions.

4-1

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Contents Page PCI-DIO24 Management committed to your satisfaction Trademark and Copyright Information Table of Contents Preface Where to find more informationAbout this Users Guide What you will learn from this users guidePCI-DIO24 block diagram Introducing the PCI-DIO24Chapter Software features Additional documentation Optional components Installing the PCI-DIO24What comes with your PCI-DIO24 shipment? HardwareInstalling the software Installing the hardware Configuring the hardwareUnpacking the PCI-DIO24 Connecting the board for I/O operations Connectors, cables main I/O connectorPin out main I/O connector Cabling Field wiring and signal terminationPCI-DIO24 Users Guide Installing the PCI-DIO24 Programming and Developing Applications Programming languages Packaged applications programsRegister-level programming DIO signals Signal level controlFunctional Details User Connector Digital I/O Lines Environmental SpecificationsPower consumption Digital input / outputBoard connector, cables, and accessory equipment Main connector and pin outUSA Declaration of ConformityMailinfo@mccdaq.com

PCI-DIO24 specifications

The Measurement Specialties PCI-DIO24 is a powerful digital input/output card designed to meet the demands of industrial automation and control applications. It provides a cost-effective and versatile solution for acquiring and managing digital signals in a variety of environments. With its robust design and advanced features, the PCI-DIO24 stands out as an essential tool for engineers and technicians working with data acquisition systems.

One of the key features of the PCI-DIO24 is its ability to support a total of 24 digital I/O channels. These channels are configurable, meaning they can be set up as either input or output, providing flexibility in applications where both types of signals need to be managed. The card operates on a standard PCI bus, ensuring compatibility with a wide range of computer systems.

The PCI-DIO24 is equipped with opto-isolated inputs, which are crucial for protecting the computer and the card from voltage spikes and noise that can occur in industrial environments. This isolation enhances the reliability of the system, allowing it to function smoothly even in harsh conditions. The card also features a 24-bit resolution for digital input signals, ensuring high precision in data collection.

In addition to its input/output capabilities, the PCI-DIO24 offers interrupt-driven data acquisition, which ensures efficient processing of incoming signals. This feature is especially beneficial in applications that require real-time response to digital events, such as monitoring sensor outputs or controlling actuators.

Another noteworthy technology integrated into the PCI-DIO24 is the ability to interface with external devices easily. The card supports standard TTL and CMOS logic levels, making it compatible with a vast array of sensors and control devices. This wide compatibility allows for easy integration into existing systems and enhances the versatility of the card.

The PCI-DIO24 is also designed with durability in mind. Its industrial-grade components ensure long-lasting performance, while the compact form factor allows for easy installation in confined spaces. The card is accompanied by comprehensive software support that facilitates smooth setup and configuration, enabling users to maximize the performance of their digital I/O tasks.

In summary, Measurement Specialties’ PCI-DIO24 is a robust digital I/O card that offers a rich set of features and technologies suitable for a broad range of applications. Its flexible configuration, opto-isolated inputs, interrupt-driven data acquisition, and compatibility with various external devices make it a reliable choice for those seeking a high-performance solution for digital signal management in industrial and automation environments.
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