ADLINK PCI-7250/7251 Relay Output Card Selection and Expansion Guide

External NPN sensor: output signal connected to DI+, sensor GND connected to IGND.

External PNP sensor: The output is connected to DI+, and the negative terminal of the power supply is connected to IGND (due to the lack of polarity in the input, it can be flexibly connected in practice, but it is necessary to ensure that the voltage is within the range).

Multi card expansion installation and configuration

5.1 Hardware Connection (PCI-7250+7251)

Insert PCI-7250 into the main PCI slot, PCI-7251 does not require a slot, and connect the two through the included flat cable (pay attention to the direction, usually 20 core or specific ribbon cable).

Up to 3 PCI-7251 chips can be cascaded, and the connection sequence is recognized by software (via onboard ID jumper or address allocation).

All cards share the same PCI bus resource, and I/O addresses are mapped by the main card. Expansion cards do not occupy additional IRQ.

5.2 Software Identification

The driver (PCIS-DASK) will automatically scan the 7251 cascaded channels and address all channels uniformly. For example, the main card channels are 0-7, the first expansion channel is 8-15, and so on. When programming, users only need to specify the channel number (0-31), without worrying about the physical location.

5.3 Address Conflict Investigation

If the system cannot detect the expansion card, check if the flat cable is securely plugged in and if the correct expansion card number is set (some versions have dip switches). If still unable to recognize, you can try replacing the main card slot or reducing the PCI bus speed.

Software support and driver installation

6.1 Operating System Support

Officially supports Windows 7/Vista/XP/2000/2003 Server and Linux (via PCIS-DASK/X). For Windows 10/11, drivers can usually be installed using Windows 7 compatibility mode.

6.2 Driver kit

PCIS-DASK for Windows: Includes DLL and sample programs (C/C++, VB, Delphi, BCB).

DAQPilot for LabVIEW: Provides a VI function library for easy graphical programming.

DAQ-MTTLB for MATLAB: used for data acquisition and simulation.

ICOM Tools (not specific to this card, but can be used with a serial port card).

6.3 Brief Programming Interface

Common functions (using C language as an example):

DASK-Open()//Open the device

DASK-GetDIOScanInfo()//Get channel information

DASK-D_ReadPort()//Read all DIs

DASK-DOWritePort()//Write all relays (outputs)

DASK-DO-ReadPort()//Read back the current output status

Each relay corresponds to an output bit (1=SET, 0=RESET), and DI corresponds to an input bit.

6.4 Terminal board and cable selection

PCI-7250/7251 uses 37 pin D-sub, recommended DIN-37D-01 (DIN rail installation) or ACLD-9137-01 (universal), cable ACL-10137-1MM (1 meter).

LPCI/LPCIe/cPCI-7252 uses 50 pin SCSI-II, recommended DIN-50S-01, cable ACL-10250-1M.

Typical application scenarios and engineering cases

7.1 Automatic assembly line signal monitoring

Using PCI-7250 main card and one 7251 chip, provide 16 channels of DI acquisition fixture in place sensors, emergency stop buttons, 16 channels of relay output to control solenoid valves and alarm lights. Isolate DI to ensure that interference from the machine tool frequency converter is not transmitted to the computer.

7.2 Aging test cabinet

Multi channel relays switch power or load, operate in sequence through the upper computer program, and read back the output status to confirm whether each channel is properly engaged. 32 channels can simultaneously control multiple sets of product testing.

7.3 Building Automation (BAS)

Use LPCI-7250 (low profile, suitable for small industrial computers) to control 8 lighting circuits (SPDT relay switchable dual power supply) and collect 8 door magnetic or infrared detectors.

7.4 Replacement of discontinued ISA/PCI cards

Many old I/O cards, such as ADLINK PCI-7230 and PCI-7248, have been discontinued. The PCI-7250 series is fully compatible with relay output and isolation DI functions, and the software interface (DASK) remains consistent, requiring only minor modifications to port old programs.

Troubleshooting and Common Problems

8.1 Relay does not operate

Check if the software correctly writes the output bit and verify using the read back function.

Check the relay drive voltage (onboard+5V drive, external load requires independent power supply, contacts only switch to external circuit).

Measure whether the contacts are conductive (the coil should be normally open and closed after being pulled in).

If all channels are unresponsive, check if the PCI slot is powered normally (+5V).

8.2 Digital input always remains high or low

Confirm whether the external signal voltage is within the effective range (0~24V) and has any polarity.

Check if the input resistance is normal (use a multimeter to measure the resistance between DI+and IGND, approximately 2.2k Ω).

If filtering is enabled, try turning it off to see if it improves (although the response may be slower, it should be detectable).

Check if the common ground is correct (IGND must be connected to the external device ground).

8.3 Expansion card cannot be recognized

Check if the cascade cable is securely plugged in and if the connection sequence between the main card and the expansion card is marked.