New EM1 expandable safety relay is even smaller

MechanControls designs and manufactures non-contact safety switches, safety interlocks, safety relays and light curtains for machine guarding applications. Here, Managing Director Mabruk Farrah relates the pathway taken with a number of its more popular products

Based in the UK, Mechan Controls produced its first RFID safety switch in 1972, and has since developed an enviable reputation. Today, tens of thousands of applications worldwide attest to the reliability of our safety switch and interlock systems. 4 years ago, we launched all-new, modular EM1 safety relay. The goal was to develop an ‘intelligently simple’ safety relay that was expandable and more importantly, non-programmable. 

After thousands of units had been sold into a variety of applications and industries, the decision was taken to further enhance the design. The main objective of the EM1 was to eliminate fault masking without the need for programming, and this was achieved using the ESM extender module. In order to achieve CAT4, SIL3, PL-e, each dual channel safety device must be connected to its own set of safety inputs. However, this method meant the old EM1 required a considerable amount of space compared to a programmable safety relay. 

The second thing we were keen to address was the limitation on the number of ESM extender modules that could be added. The previous version supports a maximum of 12 modules, due to the power limitations as each extender module draws power from the EM1 master control unit. The new EM1 is now 1/3 of the size and features a host of new advances over its predecessor. Our team of experienced hardware and software engineers has used the latest design methods to reduce the size, double the amount of extender modules that can be added and improve the diagnostic features. 

Key features include

Dual channel outputs

Dual channel inputs

No programming required (ready to use out of the box)

Expandable up to 25 ESM units (total of 26 dual channel safety devices         can be connected to one system)

Automatic or manual reset options

Cross compatibility with older model

Normally closed volt free signalling output (included on both the EM1 and ESM)


Each EM1 and ESM includes two cross monitored safety inputs that are designed to accept ANY dual channel, volt free safety device. These can include:


Emergency Stops

Non-Contact Safety Switches

Mechanical Interlocks

Foot Switches and more

It is strongly recommended that users connect one dual channel safety device per set of safety inputs to achieve CAT4, SIL3, PL-e.

Improved diagnostic features

The new EM1 design, features advanced software via the use of microcontrollers. This method of design mean that we have been able to include more ‘intelligent’ diagnostic checks. These include:

Improved safety input monitoring, this means each safety channel is now independently checked by the EM1/ESM. If a fault is detected on the safety device, it will now display which channel is faulty, allowing the user to easily diagnose the issue.

Nuisance tripping detection intelligently checks to see if the signal is a genuine fault. For example, if one channel on the safety device changes state (maybe caused by shock or vibration), it will check to see if this is a one-off fault or recurring. If it detects the signal once and it falls within the specified safe parameters, it will ignore the signal. If the problem occurs 3 consecutive times, the EM1 will go into a fault mode, turning off the output to the machine.


The new EM1 has been independently tested and approved by TUV and cULus to CAT4, SIL3, PL-e.

Mechan Controls produces a wide selection of machine guard safety products that are suitable for connection with the EM1 safety relay. The range of volt-free, non-contact safety switches can cater for ALL non-locking applications.


The Magnasafe range comprises of reed & magnet operated safety switches. Easy to install and maintain, they are fully encapsulated non-contact switches suitable for long term for use in harsh / wet environments. Available in a wide variety of sizes and contact configurations, Magnasafe switches are suitable for machine guarding applications where guard locking is not required.


The Mechan HE-Series are coded magnetic safety switches. They can be used as a standalone safety switch or combined with our SCU1 safety relay for a CAT4 SIL3 PL-e approved safety system.  The HE-Series is designed to combine the ease of use and maintenance of a simple magnetic safety switch along with the improved security, performance levels and indication of an electronic safety switch.


The S-Type range are RFID, non-contact safety switches with volt free contact outputs. The unique RFID technology features a single master code that offers protection against manipulation, interference and defeat. The electronic design provides precision switching and on-switch indication for reliable operation.


R-Type are uniquely coded RFID (Radio Frequency Identification) safety switches with volt free contact outputs. They offer protection against manipulation, interference and defeat making them ideal for use in high risk applications. These vibration-proof safety switches feature agent resistant plastic enclosures and epoxy resin for a protection level up to IP69K. The volt free contact outputs make the R-Type compatible with most safety relays on the market.

UK based manufacturer began in 1972
UK based manufacturer began in 1972
After thousands of untis had been sold the company embarked on developing an upgraded version
After thousands of untis had been sold the company embarked on developing an upgraded version
Mechan provides a variety of safety solutions for machine designers and builders
Mechan provides a variety of safety solutions for machine designers and builders
Product range is extensive
Product range is extensive

Mechan Controls Ltd

14/16 Seddon Place
Stanley Industrial Estate

+44 (0)1695 722264

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