ADLINK 7230 Series Isolation DIO Card Selection and Engineering Application Guide

ADLINK 7230 Series Isolation Digital I/O Card Selection and Engineering Application Practical Guide

Why is it necessary to isolate digital I/O? ——The 'safety guard' of industrial sites

In industrial automation, power monitoring, mechanical control, and testing measurement systems, digital I/O (DI/DO) is the most basic and critical signal interface. However, there are often hidden dangers such as common mode voltage, ground loop interference, transient surges, etc. in industrial sites, which can lead to signal misreading in mild cases and controller burnout in severe cases. Therefore, optoelectronic isolation technology has become the first line of defense to protect expensive industrial control hosts.

The 7230 series isolated digital I/O card launched by ADLINK covers various bus forms such as PCI, Low Profile PCI, PCI Express, and CompactPCI, providing 32 isolated inputs and/or outputs. The optocoupler isolation voltage is up to 2500V~5000Vrms, and the output drive current is up to 500mA/channel. It can directly drive relays, solenoid valves, and indicator lights. This article will provide engineers with a complete selection and implementation guide, covering model comparison, electrical characteristics, interruption mechanisms, and wiring techniques.

Quick overview of the entire series of models - choose according to your needs without wasting money

The core differentiation of the 7230 series lies in the input/output direction and bus interface. According to the manual, it can be divided into the following categories:

Model Bus DI Channel DO Channel Isolation Voltage Appearance Special Function

PCI-7230 32-bit PCI 5V 16 5000Vrms standard PCI DI0/DI1 interrupt

PCI-7233 32-bit PCI 5V 320 5000Vrms Standard PCI All Channel COS Interrupt, Input Logic Inverted

PCI-7234 32-bit PCI 5V 0 32 2500Vrms standard PCI Darlington current output

PCI-7234P 32-bit PCI 5V 0 32 2500Vrms Standard PCI Source Current Output (PNP)

LPCI-7230 32-bit PCI 3.3/5V 16 2500Vrms Low Profile DI0/DI1 interrupt

LPCIe-7230 PCIe x1 16 2500Vrms Low Profile DI0/DI1 Interrupt

CPCI-7230 CompactPCI 3U 16 5000Vrms 3U Eurocard DI0/DI1 Interrupt

Key engineering selection points:

Input/output bidirectional → 7230 series (regardless of bus form) is required.

Only 32 inputs are needed, and any changes in one input need to be detected → PCI-7233 (COS interrupt).

Only 32 outputs are needed to drive high current loads → PCI-7234 (current sink) or PCI-7234P (source current, suitable for PNP loads).

The chassis is half height (2U) or PCIe slot → LPCI-7230 or LPCIe-7230.

CompactPCI chassis → cPCI-7230.

Detailed Explanation of Input Characteristics - Wide Voltage, Non Polarity, State Change Interruption

3.1 Input Range and Logic Level (Taking PCI-7230/7233 as an Example)

The isolated input terminal supports non polarity design, which means that regardless of whether it is connected in a positive or negative direction, as long as the voltage difference reaches the threshold, it can be recognized. Input range is 0~24V, logic threshold:

High level (logic 1): Input voltage ≥ 5V (typical)

Low level (logic 0): Input voltage ≤ 1.5V

Input resistance: 1.2k Ω @ 0.5W (approximately) 10mA@12V ， 20mA@24V ）

Engineering meaning: It can be directly connected to 24V DC sensors (such as photoelectric switches, proximity switches) without the need for additional voltage reducing resistors. The non-polar characteristic avoids damage caused by wiring errors.

3.2 Interrupt Trigger Mechanism - Key to Real time Response

3.2.1 7230 series: Channel 0 and 1 edge interruption

PCI-7230/LPCI/LPCIe/cPCI-7230 supports external interrupts for both DI0 and DI1 channels. Users can trigger the rising or falling edge through software settings, which is suitable for signals such as emergency stop buttons, limit switches, encoders Z that require quick response.

3.2.2 7233 Series: Change of State (COS) Interrupt -32 Channel Full Coverage

PCI-7233 is a pure input card, and its biggest highlight is that all 32 channels support state change interrupts. Any change in the level of any channel (high → low or low → high) will immediately generate an interrupt request. This greatly reduces the burden of CPU polling, especially suitable for monitoring a large number of switch states, such as circuit breaker status of distribution cabinets, cabinet door magnets, alarm signals from multiple sensors, etc.

Programming note: COS interrupts require reading the interrupt status register to determine the triggering channel and clearing the interrupt flag, otherwise they will trigger repeatedly.

3.3 Input logic inversion (unique to PCI-7233)

The manual mentions that PCI-7233 has "inverted input logic", which means the input logic is opposite to the usual (high-level input may be read as 0, low-level input as 1). This may be to be compatible with certain "normally closed" sensors (such as NPN type output indicating triggering when low). Before use, it should be carefully tested or logically reversed in the software.

Detailed explanation of output characteristics - balancing driving capability and heat dissipation

4.1 Output type: Darlington transistor (sink current/source current)