Drives and Controls Magazine
Next-generation safety controller can switch 16A
Published:  16 February, 2015

Wieland Electric has announced a new generation of safety controllers which, it claims, have the largest I/O capacity on the market, the largest switching capacity (16A through one module), the largest program memory (512MB), and the fastest reaction time (12ms).

The 45mm-wide samosPro Compact controllers have been designed to compete with full-scale safety PLCs. They offer up to 20 built-in safe inputs and eight built-in safe outputs, including four configurable safe I/O. Using extra modules, the controllers can be expanded to provide up to 116 safe inputs and 56 safe outputs. Each I/O has a dedicated diagnostic LED indicator.

According to Wieland’s global industry manager, Paul Considine, the new safety controller is the most complicated product that his company has ever produced – containing around 1,700 components – yet it will cost 25–30% less than Wieland’s previous-generation controllers, while being far more powerful.

The controllers’ large switching capacity means that they can control the largest valves and contactors directly, without needing an interface relay. Each output has a wear-free, solid-state switching capacity of up to 4A.

The controllers have a built-in Ethernet port and Modbus gateway, and later this year Wieland plans to add support for Profinet and Ethernet/IP without needing separate gateways. There is also a USB port that can be configured as a gateway.

The safety modules will operate in temperatures from –25°C to +65°C – claimed to be a wider range than competing products, and opening up new potential applications in areas such as transport and cold stores. “They can be used in conditions not previously possible for such controllers,” says Considine.

He describes the controller’s configurable I/O as a “breakthrough”. Four of the I/Os can be set in software to be either inputs or outputs, allowing the controller to be tailored to specific applications and reducing the need for extra expansion modules. Considine points out that “every safety application is different, and usually needs more inputs and outputs”.

The controller’s 512MB of memory is in the form of a removable SD card with a proprietary format. This can be used to store application programs, diagnostic information and reporting data.

Wieland says that its new safety controller can be used instead of safety PLCs in many applications

There is a choice between plug-in screw or push-fit terminals.

The controllers are configured graphically using Wieland’s free samos Plan5+ project planning tool which includes more than 40 TÜV-certified function blocks for both standard and safety applications, including lifts and presses. The function blocks are said to simplify programming and to use less bit data than other systems. Users can also define their own function blocks to save time and complexity in projects.

A simulation function with a built-in logic analyser allows safety functions to be checked without the hardware being present. This can help to demonstrate compliance with the Machinery Directive, and the software can create the necessary documentation at the press of a button. The modules comply with SIL CL 3 and PL e / Cat 4 requirements.

Wieland’s new controllers can be accessed remotely for maintenance purposes and are claimed to offer “the most comprehensive diagnostic capabilities on the market”.

There is a choice between a USB-only safety controller for simpler applications, and an Ethernet version for more complex duties. The USB version has a similar cost to two safety relays.

Considine predicts that within five years, 85% of the safety control market will be using programmable devices such as the samosPro Compact, rather than safety relays.