Written by Fraser Cowie, Product Marketing Manager- Interface

There are lots of ‘Smart Relay’ solutions available today and to be honest it is difficult to choose one from another because they are all very similar and offer the same features.

They all have the same disadvantages too – in that to add more digital or analogue I/O you need more space in the cabinet and if an internal relay fails, or is not man enough to switch the load, you end up replacing the base unit or adding interposing relays – all of which increases the required installation space and adds cost!

I did a blog last year about some of Phoenix Contact hidden gems – you know – the products that don’t get much focus, but have a lot to offer. One such gem is PLC Logic, the programmable logic relay system. Let’s go into a bit more detail about why this product does not suffer the same drawbacks as conventional smart relays and so deserves your attention.

Extremely compact control and switching

PLC logic is the 1^st smart controller to combine the logic, interface and field connection levels into a single solution. This means you can switch and control I/O signals using a single compact system.

How is this achieved?

Phoenix Contact have used their existing and market leading PLC relay offer and combined them with their V8 cabling adapter, that itself has been converted in to a highly flexible and powerful logic controller or ‘smart relay’.

The logic module has eight 24V DC inputs on its COMBICON connector, two of these inputs can be configured as analogue voltage inputs (0 … 10 V). The other eight signals are connected via the PLC interface side, and each of these channels can be configured as an input or output. Depending on the relay type, the relay contacts are switched or signals are read with the input relay.

There are some new analogue modules to increase the system flexibility. These analogue modules are available as AI (current / voltage input), AO (current / voltage output), or temperature transmitter (PT100 / PT1000). Each channel can be digital, analogue, input or output!

This means maximum flexibility and 16 channels at a width of only 50mm!

The system offers all known advantages of the PLC relays: plugability for fast exchange of the relay, Solid State Relays SSR for high switching cycles, bridging of the connections and screw or push-in connection technology.

There are two different base logic modules: the SAM or Stand Alone Module and the BM or Base Module. When using the SAM module you are restricted to a maximum of 16 I/O, but with the BM module you have the ability to extend the system to 48 I/O.

How do I connect to my PLC Logic controller?

You can integrate the controller into most common field bus systems, via optional adaptable fieldbus gateways. This enables bi-directional communication with a higher level controller, as well as diagnostics and visualisation.

The base controller has Modbus RTU on board, so can be used directly with any PLC or HMI with this capability to configure and view the application.

A third option of visualisation is wirelessly via a Bluetooth adapter. This is used in conjunction with a free APP that can be installed on your smart phone or tablet. The phone or tablet can then be used to adjust parameters of the logic modules. It can be used for operation and monitoring and can access all programmed variables. The Bluetooth connection enables efficient monitoring of multiple logic modules via only one visualisation device.

How is PLC Logic programmed?

With the free software called LOGIC +

LOGIC + is available for free download on the Phoenix Contact website.  The programming is simple and intuitive and can be done via function blocks or using conventional ladder, without the need for any in-depth programming knowledge. Each configuration can be easily checked using the simulation function, where the display shows all states of your current application and any possible conflicts or errors are highlighted.

What applications are suitable for the PLC Logic?

PLC Logic can be used for any simple automation task.

Existing applications include:

• Pump control
• Sand trap scrapers in sewage plants
• Door locks control on maritime vessels
• Scissor Lifts
• HVAC / Building automation
• Paper filling systems
• Car park entry and exit control etc., etc.

So in summary, PLC Logic is an easy to use, flexible and innovative logic controller for small automation tasks, is unique on the market and can be programmed and adapted via your laptop, tablet or mobile phone!

For more information or a demonstration of the software, contact Fraser on 07584 514963 or email: fcowie@phoenixcontact.com