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:

Input channels: IDI-0~IDI-31, with every 8 channels sharing a COM terminal (COM1~COM4). For example, IDI_1~IDI_7 correspond to COM1, IDI_8~IDI_15 correspond to COM2, and so on.

Output channels: IDO-0~IDO-31, with every 8 channels sharing a VDD terminal (VDD1~VDD4) and a common IGND (output ground).

V5V: Onboard non regulated+5V power output (note current limitation, usually 200mA).

2. 7433（64DI）

All 64 pins are used for input channels IDI_~IDI_63, grouped in 8-channel groups, with each group sharing a COM terminal (COM1~COM8). No output function.

3. 7434（64DO）

All 64 pins are used for outputting channels IDO0-IDO-63, grouped in 8-channel groups, with each group sharing a VDD terminal (VDD1~VDD8) and a common IGND. No input function. CPCI-7434P/7434RP adopts a common source output, and the connection method is slightly different from the common ground version.

Wiring points:

All VDD pins must be connected to the positive pole (5-35V) of the external power supply, and IGND must be connected to the negative pole of the external power supply.

V5V is a non regulated 5V output from the board, which can supply power to a small number of low-power optocouplers or sensors, but please note that the total current does not exceed the board's capacity (200mA for 7432 output type and 150mA for 7434).

Register Structure and Programming Interface

The 743X series adopts 32-bit I/O mapping, and all register access must use 32-bit I/O instructions (8-bit or 16 bit access is not allowed). The base address is automatically assigned by PCI PnP BIOS and can be read through PCI configuration space offset 0x18h.

1. I/O address mapping

Address offset write operation read operation

Base+0x00 Output data (DO) Input data (DI low 32 bits)

Base+0x04 7434 High 32-bit DO/7432 Unused 7433 High 32-bit DI

Base+0x08 Clear Interrupt -

Base+0x40- Interrupt status

Base+0x50 LED control (R version) slot number (R version)

2. Digital input register (read-only)

7432: Base+0x00~0x03 corresponds to IDI0~IDI-31.

7433: Base+0x00~0x07 corresponds to IDI0~IDI-63 (the low 32 bits and high 32 bits need to be read twice).

3. Digital output register (write only)

7432: Base+0x00~0x03 corresponds to IDO0~IDO-31.

7434: Base+0x00~0x07 corresponds to IDO0~IDO-63 (which needs to be written in two parts: the low 32 bits and the high 32 bits).

Note: Whether the write operation is "write 1 output ON, write 0 output OFF" or vice versa depends on the output hardware structure (common ground or common source). 7432 common ground output (ULN2803A) is write 1 conductive (output low level), while 7434P common source output (TD62783) is write 1 output high level.

Interrupt system

7432 and 7433 (non 7434) support dual interrupt sources, which can be triggered by the rising or falling edge of input channel 0 (INT1) and channel 1 (INT2), respectively. Interrupt control process:

Configure interrupt source: Call _743X_Set-INT_Control (cardNo, int1Flag, int2Flag) to enable/disable INT1 and INT2 respectively.

Enable Interrupt (Windows 95): Call W_743X_INT_Snable, pass in two event handles, and when the corresponding interrupt occurs, the system will trigger the event object.

Get interrupt status: Call _743X_Get_IRQ_Status in the interrupt service routine to determine whether INT1 or INT2 is triggered.

Clear Interrupt: Write any value to Base+0x08 to clear the current interrupt request.

Interrupt application scenarios: such as event counting, emergency stop signal detection, watchdog timeout alarm, etc.

Rear I/O special function

For the cPCI-7432R/33R/34R/RP version, in addition to the standard CN1 front-end interface, it also has the following features:

LED control: Onboard 4 user programmable LEDs, controlled by the _743XR_LED (cardNo, LED_Sata) function, using only low bytes (Bit0~Bit3).

Slot number reading: By using the _743XR_SlotNo function to read the geographic address (GA0~GA4) of the cPCI backplane, the physical slot number of the current board can be obtained, which facilitates software self identification in multi card systems.

Compatibility warning: cPCI-743XR (rear wiring version) cannot be inserted into non-standard cPCI backplanes (such as other manufacturers' chassis) because the rear wiring pin definitions (J2/P2) may be different, and forced insertion may result in permanent damage.

Software Support and Programming Guide

ADLINK provides multi-level software support for the 743X series:

DOS libraries: Borland C/C++and Microsoft C++, functions are named with the prefix _743X_.

Windows 95 DLL: Functions are named with the W_743X_ prefix and support VB, VC++, and Delphi.

PCIS-DASK: Windows 98/NT/2000/XP kernel driver and DLL, with good binary compatibility.

Third party software: Provides LabVIEW VI, HP-VEE user objects, DAQBench ActiveX controls, as well as DDE Server, OPC Server, ISaGRAF/InControl drivers (some require licenses).

Core programming functions:

Function Name (Taking 7432 as an Example)

Initial_7431_Initial (&existCards,&pciInfo)

Read the number input_7432dI (cardNo,&di_data)

Write digital output _7432dO (cardNo, do_data)

Interrupt source configuration_7432_Set-INT_Control (cardNo, int1, int2)

Get Interrupt Status (cardNo,&stat1,&stat2)

Clear interrupt and write any value to Base+0x08

LED Control (R Version) _7432R_LED (cardNo, LED_Sata)

Read slot number (R version) _7432R_SlotNo (cardNo,&lot)

Common troubleshooting

Possible causes and solutions for the phenomenon

Input cannot read signal COM terminal wiring error; Check the COM connection (common ground/common source) when the input voltage is below 5V; Measure input voltage

Output unable to drive load VDD without power supply or insufficient voltage; Connect the external power supply with a load current exceeding 5-35V; Confirm that the load current is ≤ 500mA

Output constant on or off output type (common ground/common source) does not match program logic. Check hardware model (with P suffix) and adjust write logic

Interrupt not responding, interrupt source not enabled; IRQ conflict check Set-INT_Control and INT_Snable; Check the idle IRQ of the system

After cPCI, the line card cannot recognize the insertion of non-standard backboards or insufficient power supply in the slot. Only ADLINK or compatible cPCI backboards are used; Check the power supply of the chassis

Multiple card port recognition confusion, incorrect calling of Initial function, traversal of all cards using loop call _743X_Initial, obtaining the number of cards through existCards