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Connectwell Relay / Interface Modules
August 2021

Relays have come a long way from their initial applications in the control of Telegraph signals. Over the course of almost 150 years, this fundamental switch technology has expanded to almost every space where electricity plays a role. In the modern age, Relays are a key part of Automation and DCS applications where their primary protection of the DI/DO is a critical requirement. Connectwell Relay Modules are widely used in switching, protection and isolation applications, particularly in industrial automation.

While the importance of a Relay Module is well known, it’s also important to know which kind of Relay Module optimally suits your application.

Make the right Relay Module choice for the application

Smart electrical control panel designers understand how important it is to select the right type of Relay Module for the application. That’s because every application can demand a different kind of Relay Modules. For instance, the Automobile Industry requires relays to be small in size with a high current capacity. Relay Modules with DIN RAIL mounting facility and a nominal current capacity for protection are preferred in DCS applications. In other applications, the switching frequency is much more than what an Electromechanical Relay can handle.

Connectwell is capable of providing a wide variety of Relay/Interface modules for a broad range of applications. Connectwell technical experts can recommend the right product with the required specifications to match your particular application.

Different ways to classify and select a Relay Module

1) By Type

For many projects, the kind of Relay type chosen is based on project costs. However, this can lead to a mismatch with applications. Electromechanical Relays involve physical movement, hence this kind of Relay Module is not ideal for applications with high frequency switching. On the other hand, Solid State Relays are much more expensive  and so businesses may avoid this costlier solution in the initial phase of a business.

Relay Type


2) By Changeover
Depending on the logic requirement, changeover needs to be selected. Connectwell offers three types of Relay Module changeovers with multiple channels.

- SPDT Changeover - DPDT Changeover - FPDT Changeover

These are selected by the electrical engineer depending on the process application.


3) By Current Rating
Loads can change based on the process requirements. This impacts the current required to operate the load. Hence, the relay current is also an important parameter to check before selecting the right Relay Module.


4) By Dimensions
Availability of space is one of the key considerations in panel design. So, space-saving compact Relays are preferred whenever panel space is at a premium. Connectwell offers Slim Relays which are far more compact than regular relay modules.


5) By Operating Voltage
Relays can be selected based on the load voltage requirement for the project. Connectwell Relay Modules cover a range of standard voltage options such as:

- 12VDC - 24VDC - 24VAC - 110VAC - 230VAC


6) By Contact Material

Any increase in contact resistance can increase the drop across the contacts. Hence, critical applications require contacts made with materials that offers stable conductivity. Connectwell can offer specific contact material solutions based on project needs.


7) By Diode/Polarity Protection
Protection on the Relay Module comes in a wide variety of ways. Connectwell Relay Modules offer Diode/Polarity protection for your applications.

- Freewheeling Diode Protection With inductive loads, the return current can cause issues in the relay coil, particularly the DC coil. It is therefore compulsory to use freewheeling diode protection in such applications.

- Polarity Protection When the input is applied in reverse for DC voltages, then the relay coil can be damaged. Relay cards offer polarity protection of the relay coil against polarity mismatch.


8) By Fuse Protection

Relay -Module -With -Fuse -Protection -A

A. Fuse Protection - An over current from a field signal can cause a relay damage. To protect relays, Connectwell Relay Modules offer fuse protection in three different configurations
- Fuse on Input Side
- Fuse on Output Side
- Fuse with Fuse Fail Indication

B. Snubber Protection - Some sensitive applications require Relay Modules to have over-voltage protection. For these special requirements, Connectwell can customise Relay Modules to offer the protection values required.


9) Pluggable or Soldered Relays - Pluggable Relays are not recommended for all applications. In high-vibration operations, they tend to lose fitting integrity and give faulty signals. In addition, if a relay fails with the vibrations, replacing it becomes impossible.

Therefore, Connectwell offers Pluggable Relays for non-vibration applications, as well as Soldered Relay Modules for vibration applications, with all available channels, changeovers and voltages.


10) By Mounting Option
Different applications require different mounting positions. Connectwell offers Relay Modules in DIN mounting as well Panel mounting options.


11) By Number of Channels
The number of relays change as per the DI and DO in an automation application. Instead of using an independent relay for each DI and DO, Connectwell offers Relay Modules with multiple channels to save space.
Standard numbers of Channels / Relays are 1, 2, 4, 6, 8, 12, and 16.


12) By Common Bussing Possibilities
To reduce wiring time, Connectwell Relay Modules offer different bussing possibilities.

- Common Negative Relay Module - to save time as well as extra wire usage.
- Common Positive Relay Module - for special applications.
- Standard Relay Module - bussing possibility for common negative as well common positive. Modules are provided with switchable jumpers to make a common positive or common negative relay module.


13) By type of wiring connection
In today’s fast-paced world, ever quicker implementation times have become important. Connectwell Relay / Interface Modules offer quicker wiring times with Spring-clamp connection technology. Traditional, Screw connections are also available for projects that are not as time-sensitive.

Screw Spring Connection


14) By Life Expectancy
Physical movement, or using high currents beyond the rating of a Relay Module, can cause premature contact damage and shortened product life expectancy. Connectwell Relay Modules are designed to operate under full-load conditions beyond the required rating benchmarks to ensure maximum life expectancy.

Choosing Connectwell Solid State Relays

As you can see, there are a wide variety of Relay /Interface Modules that are used inindustrial automation. While your choice of Relay Module can vary based on your project and application needs, Connectwell assures higher performance standards no matter which Relay / Interface Module you require. From raw materials to machining fabrication and testing,Connectwell Relay /Interface modules are built to specifications that meet industrial standards in Process Automation, Electrical, Machine Building, Transportation and the Oil & Gas industry.

For more information or to explore an optimal Relay/Interface Module solution for your industrial application, contact us here.