ADLINK PCI-7250 Series Relay Output and Isolation Input Card Configuration and Protection Circuit Guide

In industrial automation control systems, the on/off control of relays and reliable acquisition of external switch signals are the most fundamental and critical requirements. Whether driving high-power contactors, controlling solenoid valves, or monitoring limit switch status, I/O cards are required to provide sufficient driving capability, electrical isolation, and anti-interference performance. ADLINK PCI-7250 series relay output and isolation digital input card provides 8 relay outputs (including Form C and Form A types) and 8 optocoupler isolated inputs, supports AC/DC signal access, can select AC filtering or non filtering mode through jumper, and is equipped with onboard LED to indicate relay status. This series covers multiple bus specifications including PCI, CompactPCI, Low profile PCI, and PCI Express, and can flexibly adapt to various industrial control platforms. This article will systematically explain the engineering application points of the PCI-7250 series from hardware configuration, pin definition, register programming, relay protection circuit to software support.

Product Family and Core Features

The PCI-7250 series includes the following models:

PCI-7250: Standard PCI specification, 8 relay outputs (R0~R3 are Form C, R4~R7 are Form A)+8 optocoupler isolated inputs, onboard LED indicates relay status.

PCI-7251: The expansion board of PCI-7250 provides an additional 8 relay outputs (all Form C) and 8 isolated inputs per board, with a maximum of 3 boards mounted, expanding the total number of channels to 32.

CPCI-7252: CompactPCI 3U specification, 8 relay outputs (all Form C)+16 isolated inputs, suitable for high-density rack mounted systems.

LPCI-7250: Low profile PCI specification, 8 relay outputs (all Form C)+8 isolated inputs, suitable for compact chassis.

LPCIe-7250: PCI Express x1 specification, with 8 relay outputs (all Form C) and 8 isolated inputs, suitable for modern motherboards without PCI slots.

All models adopt optoelectronic isolation technology (with a maximum isolation voltage of 5000Vrms) to completely isolate the on-site side from the PC ground, effectively suppressing common mode interference and surge impact. Rated capacity of relay contacts: AC 120V@0.5A Or DC 24V@1A (Partial models DC) 30V@2A ）It can directly drive small and medium-sized loads.

Hardware installation and jumper configuration

2.1 Unpacking and Anti static Treatment

The board is an electrostatic sensitive device and must be operated on an anti-static workbench, wearing a grounding wristband. Check the contents of the packaging: main card, ADLINK CD, software installation guide, and this manual. If there are any missing or damaged items, please contact the dealer.

2.2 Jumper Setting (AC Filter Selection)

PCI-7250/7251, LPCI-7250, and LPCIe-7250 are equipped with 8 sets of jumper wires, JP1~JP8, corresponding to DI0~DI7, respectively, used to select whether the input signal has undergone AC filtering:

Jumper corresponding channel function

JP1~JP8 DI0~DI7 1-2: AC filtering (AC signal, filtering out 50/60Hz noise)

2-3: Non AC filtering (DC signal, default)

Selection suggestion: If the input signal is an AC powered sensor (such as an AC proximity switch), it is recommended to enable AC filtering to eliminate false triggering caused by power frequency interference; If it is a DC signal (24VDC switch), use non AC filtering mode to obtain the fastest response speed.

2.3 PCI/PCIe slot installation

Turn off the power of the computer and all peripherals, and remove the chassis cover.

Select an idle PCI/PCIe slot, align the board and insert it, ensuring that the gold fingers are fully in contact, and secure the baffle with screws.

For cPCI-7252, insert it into the I/O slot of the CompactPCI chassis.

2.4 External connector (CN1)

The pin definitions for different models vary, please refer to Tables 2-3 to 2-5 in the manual for details. Taking PCI-7250 as an example:

Relay terminals: Each relay provides three terminals (Form C): COM (common), NO (normally open), and NC (normally closed), or COM+NO (Form A).

Digital input: DI0~DI7 are input signal terminals, IGND is common ground. Input does not need to distinguish polarity (optocoupler bidirectional), both AC and DC are acceptable.

PCI-7251 Expansion Connection: Connect PCI-7250 to PCI-7251 via a flat cable, with up to 3 expansion boards, automatically recognized by the system. The register mapping of the expansion board is from Base+2 to Base+7.

Register Mapping and Low Level Programming

The PCI-7250 series uses the PLX PCI-9050 bridge chip, and the system BIOS automatically assigns I/O base addresses. The base address can be read by offsetting the PCI configuration space by 18h. All registers are 8-bit.

3.1 PCI-7250 (including extensions) Address Mapping

Offset (hexadecimal) write operation, read operation corresponding to the card

0x00 relay output reads back to PCI-7250 motherboard

0x01 Unused isolated input PCI-7250 motherboard

0x02 Relay output readback PCI-7251 # 1

0x03 Unused isolated input PCI-7251 # 1

0x04~0x07 Same as above PCI-7251 # 2/# 3