ADLINK 7230 Series Isolation DIO Card Selection and Engineering Application Guide

7.1 Input wiring - prevent accidental triggering

Due to the input impedance of 1.2k Ω, for long-distance transmission (>10 meters), it is recommended to use shielded twisted pair cables, with the shielding layer grounded at one end (to the ground at the site).

If the sensor is a dry contact (passive contact), an external pull-up resistor should be connected to 24V (reference input current is about 10-20mA) to ensure a reliable high level when closed.

Non polar input allows reverse connection, but it is recommended to maintain consistent polarity for easy troubleshooting.

7.2 Output wiring - back electromotive force suppression

When driving inductive loads such as relays and solenoid valves, freewheeling diodes (such as 1N4007 or 1N5819) must be connected in reverse parallel at both ends of the load. Otherwise, the induced electromotive force (up to several hundred volts) generated at the moment of shutdown will break through the Darlington transistor, causing permanent damage.

7.3 Power isolation and common ground

The external output power supply (VEXT) should be completely isolated from the digital ground (GND) of the PC host, and the optocoupler should provide an isolation barrier. Do not directly connect the external power ground to the GND of the PC, otherwise it will damage the isolation effect.

If multiple boards share an external power supply, it is necessary to ensure that the power capacity is sufficient (such as 24V/2A or above).

Quick Guide to Interrupt Programming (Based on PCIS-DASK)

Taking the DI0 interrupt of PCI-7230 as an example (code style reference manual example):

Open the device DASK-DevOpen to obtain the device handle.

Set the interrupt trigger edge (rising/falling) through DASK-DI-INt_Start or similar functions (please refer to the DAQPilot API for specific function names).

Register an interrupt callback function, read the input port value in the callback, and clear the interrupt state.

The main program enters a waiting loop and automatically jumps to callback when an interrupt occurs to handle emergency events.

For the COS interrupt of PCI-7233, it is necessary to read the interrupt status register to determine the specific change channel, and then process the corresponding logic.

Troubleshooting and Frequently Asked Questions (FAQ)

Q1: Does the system fail to recognize PCI-7230 after installation?

Check if the PCI slot on the motherboard supports 5V signal (32-bit PCI). Some new motherboards only support 3.3V, so LPCI-7230 (supporting 3.3/5V universal) should be selected. If PCIe is used, LPCIe-7230 must be selected.

Q2: The input status remains high/low regardless of external signals?

Check if the external input voltage is within the range of 5-24V; Check if the COM terminal wiring is correct (non-polar input, but still requires positive and negative connections); Measure the voltage of the input terminal to COM with a multimeter to confirm if the threshold has been reached.

Q3: The output cannot drive the load, even if the program outputs 1?

Confirm that the external power supply (5-35V) has been correctly connected to the power supply terminals of the board (usually VEXT and GND). The Darlington output has an open collector internally and must be connected to an external pull-up resistor or directly connected to the load to the positive power supply (current sink type). If using PCI-7234P source current type, connect one end of the load to OUT and the other end to GND.

Q4: When multiple channels are output simultaneously, does the board heat up severely?

Please check if the total current exceeds the recommended value in the manual. It can reduce the duty cycle (using PWM) or decrease the number of channels conducting simultaneously, and if necessary, install a cooling fan. Long term high temperature will shorten the lifespan of optocouplers.

Q5: Does the COS interrupt of PCI-7233 not trigger?

Confirm that the interrupt enable bit has been correctly set; To confirm whether the input signal edge is clean (jitter may cause multiple triggers), software debounce or hardware RC filtering can be added.