ADLINK USB-7230/7250 Isolation I/O Module Operation Manual

ADLINK USB-7230/7250 Isolated Digital I/O Module Complete Application and Operation Guide

In the field of industrial automation testing and control, high voltage isolation, reliable digital signal monitoring and driving capabilities are the foundation for stable system operation. ADLINK USB-7230 and USB-7250, two digital I/O modules based on USB 2.0, provide engineers with a plug and play cost-effective solution with up to 2500V RMS isolation voltage, flexible channel configuration, and multifunctional installation. This article is based on the original hardware manual, providing a comprehensive interpretation of hardware architecture, pin definitions, functional operations, and software configuration. It also offers design suggestions in conjunction with practical engineering scenarios to help developers quickly get started and avoid common misconceptions.

Product positioning and selection differences

USB-7230 and USB-7250 cater to different output driver requirements:

USB-7230: Provides 16 optoelectronic isolated digital inputs, 16 isolated digital outputs (open drain MOSFET, maximum 250mA current per channel, 5-35V power supply), and 2 frequency/event counters. Suitable for scenarios that require a large number of digital outputs to drive small relays, LED indicator lights, or solid-state switches.

USB-7250: Provides 8 differential isolated digital inputs and 8 electromagnetic relay outputs (channels 0-3 are C-type relays, including normally open/normally closed/common terminals); Channels 4-7 are A-type relays, only normally open, and are also equipped with two counters. Suitable for situations where direct switching between AC/DC loads (up to 220VDC/250VAC, 2A) is required.

Both use USB bus power supply (5V @ 400mA), without the need for external power supply, and come standard with detachable screw terminals, multifunctional brackets (supporting desktop, DIN rail, and wall mounting), and locking USB cables to ensure reliable connection on industrial sites.

Detailed explanation of hardware interfaces and pin definitions

1. USB-7230 pin allocation (40 pin terminal)

The module provides two sets of 20 pin detachable terminals, with the following pin functions:

Pin signal Pin signal

1 DI0 21 DI8

2 DI1 22 DI9

3 DI2 23 DI10

4 DI3 24 DI11

5 DI4 25 DI12

6 DI5 26 DI13

7 DI6 27 DI14

8 DI7 28 DI15

9 COM 29 COM

10 CNT0 30 CNT1

11 CGND 31 CGND

12 DO0 32 IGND

13 DO1 33 DO8

14 DO2 34 DO9

15 DO3 35 DO10

16 DO4 36 DO11

17 DO5 37 DO12

18 DO6 38 DO13

19 DO7 39 DO14

20 VDD 40 DO15

Signal Description:

DI0~DI15: Isolated digital input, common terminal is COM. The input voltage ranges from 5 to 24V at high levels and 0 to 1.5V at low levels, and can also be connected to dry contacts (passive contacts). All inputs share a common COM, so when wiring, the reference ground or power common terminal of all DIs must be uniformly connected to the COM.

CNT0/CNT1: Input for frequency/event counter, reference ground is CGND. Supports up to 1MHz input frequency, 32-bit counting width, and can be triggered by software selection of rising or falling edge.

DO0~DO15: Isolated digital output, using open drain MOSFET structure, with IGND as the reference ground. The external load power supply needs to be connected to VDD (5-35V), with a maximum current of 250mA per channel (100% duty cycle). When DO is ON, MOSFET conducts, and current flows from VDD through the load into the DO pin and then to IGND.

VDD: The positive input of the external output power supply must be connected to the positive terminal of the load power supply.

2. USB-7250 pin allocation (40 pin terminal)

Pin signal Pin signal

1 DI0H 21 DI0L

2 DI1H 22 DI1L

3 DI2H 23 DI2L

4 DI3H 24 DI3L

5 DI4H 25 DI4L

6 DI5H 26 DI5L

7 DI6H 27 DI6L

8 DI7H 28 DI7L

9 NC0 29 NC0

10 NO0 30 COM0

11 NO1 31 COM1

12 NC1 32 NC1

13 NO2 33 COM2

14 NO2 34 NC2

15 NO3 35 COM3

16 NC3 36 NC3

17 NO4 37 COM4

18 NO5 38 COM5

19 NO6 39 COM6

20 NO7 40 COM7

(Note: Some pins in the table are duplicated, and there are layout differences in tables 1-3 of the original manual. In reality, the signal name should prevail: channels 0-3 are of type C, with COM, NO, and NC terminals.); Channels 4-7 are of type A, with COM and NO terminals. Please refer to Table 1-4 in the manual for specific details

Signal Description:

DI0H/DI0L~DI7H/DI7L: Differential isolated input pair. Each channel is independent, without a common terminal, and can be connected in any polarity (bidirectional), with a high level of 5-24V and a low level of 0-1.5V.

CNT0/CNT1: Same as USB-7230, but the reference ground is GND0/GND1 (independent ground terminal).

Relay output: COM is the common terminal, NO is the normally open terminal, and NC is the normally closed terminal (only channels 0-3). When the control bit is 1, COM and NO are conductive; When it is 0, COM and NC are conductive (type A relay is disconnected). The rated power of the contact is 60W/125VA, the switching voltage is 220VDC/250VAC, the current is 2A, the action time is about 2ms, and the release time is 1ms.

Core Function Operation and Configuration

1. Isolate digital input and dry contact detection

USB-7230: All inputs share COM and can be connected using "common ground" or "common source". If an external NPN sensor (with a valid output low level) is connected, the sensor output can be connected to DI, the sensor common terminal can be connected to COM, and COM can be connected to the positive pole (common source) of the external power supply; If connected to PNP type, connect COM to the negative pole of the power supply (common ground). The input resistance is about 2.4k Ω (0.5W), ensuring normal operation within the range of 5-24V.

USB-7250: Each channel is differentially independent, without considering polarity, and can be directly connected to passive contacts (such as DIH and DIL at both ends of the switch) or active signals (DIH at the positive end and DIL at the negative end), greatly simplifying on-site wiring.

2. Change of State (COS) detection

The COS function can monitor the logic level transition (rising edge or falling edge) of a specified input channel and generate interrupt notifications to the upper computer. The module uses a 48MHz base clock for sampling internally, with a minimum detectable pulse width of 20.83ns (1/48MHz). When a channel with COS enabled undergoes a transition, the corresponding input data is latched into the COS latch register, which is automatically cleared after reading the register. Attention: Due to software response delay, it is recommended that the COS trigger frequency not exceed 1kHz, otherwise events may be lost.

3. Frequency/Event Counter

The counter is based on a 32-bit addition counter, which can count the number of rising or falling edges of the input signal (event counting mode), or measure the signal frequency (frequency mode). Frequency measurement principle: Count the number of 48MHz base clocks within a complete signal cycle (between adjacent rising or falling edges), and then convert them into frequency values. The frequency range is 0.1Hz~1MHz, and the measurement error increases with frequency - ≤ 0.5% for ≤ 50kHz, ≤ 1% for 50kHz~500kHz, and ≤ 2% for 500kHz~1MHz. For low-frequency signals, digital filters can be used to eliminate jitter.

4. Digital filtering

The filtering function is disabled by default for all DI and counter inputs. After activation, the minimum pulse width value (filtering level N, N=1~65535) needs to be set. The actual minimum pulse width is N × 20.83ns. Any pulse with a width less than this value will be ignored, effectively suppressing false triggering caused by contact jitter or electromagnetic interference. For example, if N=10, signals with pulse width<208.3ns will be filtered out.

5. Isolated digital output (USB-7230)

The output adopts an open drain structure, and an external load must be connected to VDD (5-35V). When the output is logic 1 (ON), the MOSFET conducts, and the load current flows through the load into the DO pin and then to IGND. Important reminder: If driving an inductive load (such as a relay coil), a freewheeling diode must be connected in parallel at both ends of the load (with the cathode connected to VDD and the anode connected to DO), otherwise the reverse induced voltage generated when turning off will break down the MOSFET. The module supports programming the initial output state when powered on, and can set the default state of each channel before the driver is loaded to avoid misoperation at the moment of power on.

6. Relay output (USB-7250)

The relay is a mechanical non latch type, and when the control position is 1, the excitation coil causes the contacts to close. C-type relays (CHO~3) provide normally closed contacts, suitable for applications that require failure protection (such as maintaining continuity during power outages); Type A (CH4-7) is only normally open. The lifespan of the relay can reach 1 million operations under resistive loads (50VDC/0.1A), and higher loads will shorten the lifespan. It also supports the initial power on state setting, but please note that the relay automatically returns to a low state when reset or USB is disconnected (COM and NC are conductive, type A is disconnected).

Installation, Connection, and Device Identification

1. Mechanical installation

The module size is 156.5 × 114 × 41.3mm, matched with a multifunctional bracket. Installation steps:

Desktop placement: Simply slide the module into the bracket until it clicks.

DIN rail: Use the included rail mounting kit (spring clip) to pre hang the module on the rail and press it in place.

Wall mounted: Fixed to the wall with countersunk screws through four mounting holes with a diameter of approximately 3.4mm on the back of the bracket.

2. USB connection and driver

Connect the standard locking USB cable (2 meters) to the computer USB 2.0 port. When first inserted, the system automatically recognizes and loads the firmware, and the LED indicator light changes from amber to green to indicate readiness. The module is only powered by USB (maximum 400mA). If connected to a USB hub or a port with insufficient power supply, it may cause recognition failure. In this case, a USB hub with an external power supply should be used.

3. Device ID setting

There is a rotary switch (0-7) on the back of the module for setting the device ID. When multiple modules of the same model are connected to the same computer, a unique ID must be assigned to each module, otherwise the software cannot distinguish them. This ID is independent of the USB port number, making it easy to map fixed devices.

Software Support and Testing Tools

ADLINK provides UD-DASK driver library (supporting 32/64 bit Windows 7/Vista and higher versions), as well as DAQPilot graphical SDK, which can lower the programming threshold. In addition, the free tool U-Test can directly operate all functions without writing code - it can be used to quickly verify hardware connections, monitor input status, manually control outputs, view counter readings, and perform FFT analysis. It is recommended to first use U-Test to confirm that the module is working properly during on-site debugging, and then proceed with development.

Engineering application precautions

Input voltage range: DI high level with a minimum of 5V. If using 3.3V logic, a level conversion circuit needs to be added.

Output current limit: USB-7230 has 250mA per channel, but the overall power consumption is limited by USB power supply (5V × 400mA=2W). The total current when all channels are conducting simultaneously needs to be calculated and must not be exceeded.

Relay contact protection: When switching AC inductive loads (such as motors), it is recommended to parallel RC absorption circuits or varistors at both ends of the contacts to reduce arc erosion on the contacts.

Grounding and isolation: Although the module provides 2500V isolation, the internal isolation between different grounds such as input COM, IGND, CGND, etc. must not be short circuited externally, otherwise the isolation performance will be damaged.

Electrostatic protection: Before disassembling the terminal, make sure to turn off the power and avoid touching the pins to avoid damaging the optocoupler or MOSFET.

Common troubleshooting

Possible causes and solutions for the fault phenomenon

LED does not light up or remains amber. USB power supply is insufficient or the driver is not installed. Replace the motherboard USB port or external power hub; Reinstall UD-DASK

Input signal cannot detect COM wiring error (7230) or differential polarity reversal (7250). Check if COM is connected to the power common terminal; 7250 interchangeable DIH/DIL

Output unable to drive load VDD without power supply or voltage too low; Connect the external power supply of 5-35V when the load current exceeds the limit; Check the load impedance

The counter reading jumps and the input signal shakes or exceeds the frequency limit, enabling digital filtering; Confirm frequency ≤ 1MHz

Is the control bit written correctly when the relay does not engage? Measure the coil resistance (usually tens of ohms) with a multimeter to determine if there is an open circuit due to contact oxidation or overload burnout