ADLINK ACL-7225B Relay Isolation Input Card Guide

ADLINK ACL-7225B 16 Channel Relay and Isolation Digital Input Card Deployment and Maintenance Guide

In industrial automation control systems, the output and isolated input of switch signals are the fundamental links that connect digital controllers with on-site actuators and sensors. Whether driving solenoid valves, contactors, indicator lights, or monitoring limit switches and button status, reliable and electrically isolated I/O interfaces are required. ADLINK ACL-7225B is a 16 channel relay output and 16 channel optocoupler isolated digital input card based on ISA bus, designed for industrial ON/OFF control, energy management, laboratory automation, and external high-power relay drive scenarios. This card provides 16 Double Pole Double Throw (DPDT) relays (some of which are Form C and some are Form A) with contact ratings of 120VAC/0.5A or 24VDC/1A, which can directly drive small and medium power loads; Simultaneously providing 16 optocoupler isolation inputs, supporting AC or DC signals (polarity independent), with an isolation voltage of 1000V, effectively eliminating ground loops and transient interference. This article will provide engineers with a complete engineering application manual from the aspects of hardware architecture, jumper configuration, base address setting, input signal type selection, relay type differentiation, connector pin definition, register programming, and relay protection circuit design, especially suitable for upgrading old production lines or maintenance replacement of ISA bus systems.

Product positioning and typical application scenarios

ACL-7225B is a compact ISA bus board with a half length PCB size, which is connected to external signals through two 37 pin D-type connectors (one of which is converted through a 40 core flat cable). Its core value lies in:

16 relay outputs: can directly control AC or DC loads without the need for additional power drive circuits (but for high current loads, external contactors are still required).

16 channel optocoupler isolated input: supports 5~24V AC/DC signals, with optional response time (20 μ s without filtering, 2.2ms with AC filtering), suitable for different noise environments on site.

LED status indication: Each relay corresponds to a red LED, which intuitively displays the power on status for easy on-site debugging.

Fully isolated architecture: 1000V channel to channel and channel to ground isolation to ensure PC safety.

Typical applications include:

Motor start stop and valve switch control on industrial production lines;

The contactor coil drive in the distribution cabinet;

Monitoring the status of sensors (proximity switches, photoelectric switches);

Signal routing and switching in laboratory automation;

Old equipment renovation, replacing discrete relay arrays.

Hardware installation and jumper configuration

2.1 Anti static treatment and unpacking inspection

ACL-7225B contains electrostatic sensitive components. Before operation, it is necessary to wear a grounded wristband and operate on an anti-static pad. Check packaging contents: board card, two DB-37 male connectors (for cables), 40 pin to DB-37 flat cable converter, ADLINK driver CD, and user manual. If any physical damage is found, do not turn on the power.

2.2 Base Address Setting (SW1 DIP Switch)

ACL-7225B occupies 8 consecutive addresses in the I/O space (only the first 4: BASE~BASE+3 are actually used). The base address is set through a 6-digit DIP switch SW1, with a range of 0x200~0x3FF and a default of 0x300. DIP1~DIP6 correspond to address lines A3~A8 respectively (A9 is fixed as 1, A0~A2 are fixed as 0). When setting the base address, it is necessary to ensure that it does not conflict with PC built-in devices (such as COM/LPT) or other expansion cards. For example, by default 0x300, its binary A9~A3 are 1 1 0 0 0 0, corresponding to DIP1~DIP6 being OFF ON ON ON ON (see Table 2.1 in the manual for details). If it needs to be changed to 0x220, the corresponding bit needs to be adjusted.

2.3 Selection of Input Signal Types (JP1~JP16)

Each isolated input can be independently configured as an AC input or DC input, achieved through the corresponding jumper cap. 16 jumper wires (JP1 corresponds to DI0, JP2 corresponds to DI1,..., JP16 corresponds to DI15) are set to the DC position by default (i.e. skipping the middle two pins). If the on-site input is an AC signal (such as 50~1000Hz AC voltage), the corresponding jumper needs to be moved to the AC position. At this time, a filtering circuit will be added internally, and the response time will be extended to 2.2ms, but it can effectively suppress false triggering. For DC signals (5~24V), maintaining the DC position with a response time of only 20 μ s is suitable for high-speed switch detection.

Attention: When the input is AC, due to the bidirectional LED structure inside the optocoupler, there is no need to distinguish polarity, and any connection can be made.

Pin allocation of connectors and cable conversion

The board provides two physical connection methods:

CON2: 37 pin D-type female socket directly located on the blocking plate (can be directly plugged with standard DB-37 cable).