ADLINK cPCI-7432/7433/7434 isolated I/O card

ADLINK cPCI-7432/7433/7434 64 Channel Isolated Digital I/O Board Complete Technical Manual

In industrial automation control systems, high-density digital input/output (I/O) is the foundation for connecting sensors, actuators, and controllers. In the face of common ground loop interference, electrostatic discharge (ESD), and transient overvoltage in harsh industrial environments, optoelectronic isolation technology has become the key to ensuring stable system operation. The ADLINK 743X series 64 channel isolated digital I/O cards cover PCI-7432 (32DI/32DO), PCI-7433 (64DI), PCI-7434 (64DO) and their CompactPCI (cPCI) and Rear I/O versions, providing up to 5000Vrms of channel computer isolation voltage and up to 500mA/channel high current output capability. They are widely used in scenarios such as laboratory automation, industrial control, event counting, frequency measurement, and watchdog timers. This article is based on the original factory technical manual, systematically analyzing its hardware architecture, isolation principle, pin definition, register operation, and software library functions, providing engineers with complete selection, integration, and programming references.

Overview of Product Family and Key Selection Points

The 743X series covers two bus forms, PCI and 3U CompactPCI, and provides R/RP versions for rear wiring applications. The specific models are as follows:

Model Bus Digital Input Digital Output Isolation Voltage Output Type

PCI-7432/cPCI-7432/cPCI-7432R PCI/cPCI 32CH 32CH 5000Vrms (R version 2500V) Common Ground (ULN2803A)

CPCI-7432RP cPCI Rear I/O 32CH 32CH 2500Vrms Common Source (TD62783)

PCI-7433 / cPCI-7433 / cPCI-7433R PCI / cPCI 64CH — 5000/2500Vrms —

PCI-7434/cPCI-7434/cPCI-7434P PCI/cPCI-64CH 5000Vrms common ground/common source optional

CPCI-7434R/cPCI-7434RP cPCI Rear I/O-64CH 2500Vrms common ground/common source optional

Selection key:

If you need to simultaneously perform a large amount of signal acquisition and output control, choose the 7432 series (32 in/32 out).

If only a large number of switch signals (such as limit switches, button arrays) need to be monitored, select 7433 (64 input).

If you need to drive a large number of relays, solenoid valves, or indicator lights, choose 7434 (64 output).

For cPCI chassis and for easy maintenance and wiring, choose the version with R or RP suffix and match it with the corresponding rear wiring transition board (DB-100RU).

Isolation principle and electrical specifications

1. Isolate digital input

The input of the 743X series adopts a optocoupler structure, with a light-emitting diode on the input side and a phototransistor or Darlington array on the output side. The input voltage range is 0~24V (7433 supports 0~50V), with a logic high level of 5~24V and a low level of 0~1.5V. The input resistance is 2.4k Ω (0.5W), and 7433 is 2.4k Ω (1W) or 4.7k Ω. Each input channel is physically isolated from the PC bus through optocouplers, with an isolation voltage of up to 5000Vrms (PCI-7432/7434 and cPCI standard versions) or 2500Vrms (R/RP version and 7433 series).

Common ground/common source connection:

The input signal can be connected in two ways: "Current Sink" or "Current Source". If the external signal source is an NPN sensor (outputting low level), the common source method should be used, that is, the COM terminal should be connected to the positive pole of the power supply, and the signal line should be connected to the DI channel; If it is a PNP sensor, use a common ground method and connect the COM terminal to the negative terminal of the power supply.

Each input channel is grouped into groups of 8, with each group sharing a common COM terminal. For example, input channels 0 to 7 of 7432 share COM1, 8 to 15 share COM2, and so on.

2. Isolate digital output

The output channel uses a Darlington transistor array (ULN2803A or TD62783) as an open drain output, requiring an external pull-up load to VDD (5-35VDC).

Common ground output (ULN2803A): When the output is logic high (ON), the transistor conducts, and current flows from the external VDD through the load into the output channel, and then into IGND. Suitable for driving relay coils, LED lights, etc., with a maximum current of 500mA per channel (single channel) or 2.25W/device.

Common source output (TD62783): The output terminal directly provides a high level (VDD), suitable for driving loads that require positive voltage.

Inductive load protection: When driving inductive loads such as relays and motors, Flywheel diodes must be connected in parallel at both ends of the load, with the cathode connected to VDD and the anode connected to the output channel. Otherwise, the reverse induced voltage (up to several hundred volts) generated at the moment of output shutdown will break through the Darlington transistor.

Output throughput rate: up to 10kHz (0.1ms), suitable for medium and low-speed switch control.

Detailed explanation of connector pin allocation

The 743X series all use 100 pin SCSI-II type connectors (CN1), with different pin functions for different models.

1. 7432（32DI/32DO）

The pins of CN1 are divided into four groups: