LedControl DC – UV LED control in category 4, PL e and SIL 3

One DC power supply unit each is needed to operate the LedControl DC and the LED module. At the 24 V auxiliary voltage the LedControl DC needs an output power of 10 W; the output power for the LED system depends on the module and lies between about 20 W and about 2000 W.

A two-channel safety door monitoring with automatic start is shown in the following example. Compared with simply separating the DC voltages, the advantage is the monitoring of the external contactors. The example is suitable up to category 4, PL e (EN ISO 13849-1) or SIL 3 (EN 62061), provided that cross-faults in the control of the actuator and in the sensor circuit can be excluded.

With the PL+ extension we supply all components ready-assembled for simple integration into a plant.

The LED systems that suit the LedControl DC have separate connections for the power supply and for the control. A seven-pole M23 flange plug for the power is built into the LED system; the control runs separately through a twelve-pole M23 flange plug.

Pre-assembled cables with sockets and open cable ends are available as a cable set. The standard length is 10 m; further cable lengths and intermediate sockets are available on request.

To make machines safe and to meet the requirements of the machinery directive 2006/42/EC, safety functions are needed in the controls. Usually the required performance level PLr is determined for every safety function. This is where the first difficulty with UV installations begins: the severity of the injury, the frequency and duration of exposure and the avoidance of the UV hazard have to be determined.

In the short term, UV exposure of the skin leads to erythema, elastosis and skin cancer; exposure of the eye can lead to photokeratitis, conjunctivitis and cataractogenesis. Skin cancer is a severe and usually irreversible injury.

Directive 2006/25/EC on artificial optical radiation permits regular exposure up to a daily exposure limit of 30 J/m². The severity of the injury can therefore be reduced through the duration and the intensity of the exposure without having to achieve absolute zero exposure: if the limit is observed, healthy adults can be expected to be exposed repeatedly without acute harmful effects. In the event of a fault, a short exposure may cause a reversible injury such as a slight erythema. The boundary is not reliable, however, and measures and safety functions are needed in every case.

Measurements are possible on existing installations; during the planning phase they are not, or only with additional effort, which is why a higher PLr is often demanded. This is exactly what the LedControl and the PLready option are for - already at the planning stage.

The PLready safety option is suitable up to PL category 4 according to EN ISO 13849-1 and SIL 3 according to EN 62061, provided that cross-faults in the control of the LED module and in the sensor circuit can be excluded.

It works with a safety extra-low voltage (SELV) of 48 VDC that is safely separated by an external circuit and can switch the LED modules off completely in the event of a fault.

The optional shutdown for the performance level separates the LED modules through an external contact:

A two-channel safety door monitoring with automatic start is shown in the following example. Compared with simply separating the DC voltages, the advantage is the monitoring of the external contactors. The example is suitable up to category 4, PL e (EN ISO 13849-1) or SIL 3 (EN 62061), provided that cross-faults in the control of the actuator and in the sensor circuit can be excluded.

The LedControl DC can be controlled through the optional programming interface - USB, RS485 or RS232 as required. Communication uses ASCII, here with "switch on" as an example:

• the control sends: LOnOff:1!
• the LedControl answers: LOnOff: 1 (CRC-16)

Every channel can be controlled individually. Remote software for testing the programming interface straight away is available.

Through the PLC interface option the LED power (0 to 10 V), switching on and off (trigger input 24 V) and the status (trigger output 24 V) are set and queried. With its robust signals this option suits simple integration into a plant.

Control uses short ASCII commands. A selection:

The test and control software shows the channels with intensity and status, switches them individually, sets timers and presets and logs the communication with the device.

The device emits UV-A and blue light. UV radiation is invisible. Any visible light is only luminescence excited by the radiation; it is usually much weaker than the exciting UV radiation. The irradiance of the device is several hundred times stronger than that of sunlight.

UV-A radiation can cause cataracts in the lens of the eye and inflammation of the retina. Always wear suitable UV protective goggles when operating the device. UV-A also causes skin discolouration and skin ageing; use suitable clothing, gloves and further personal protective equipment - depending on the irradiation dose.

The devices are designed and classified according to DIN EN 62471:2009-03 "Photobiological safety of lamps and lamp systems"; the LED modules fall into risk group 3. Do not look into the LED and do not expose the skin to the UV radiation permanently.

We are glad to support you in setting up UV workplaces and with the risk assessment according to DIN EN 14255:2005.

The LedControl DC drives one UV-LED module at 24 V and is mounted on a DIN rail.

Scope of delivery: the LedControl DC, the interface assignment, the operating manual and the options ordered. Please state the LED type, the wavelength and, where applicable, the optic and the options with your order.

With the extension the control reaches performance level e according to ISO 13849 and SIL 3.

* including the PLC interface option.

The cable set holds pre-assembled cables with sockets and open cable ends for the power and for the control; the standard length is 10 m. Further cable lengths and intermediate sockets are available on request.

The order numbers of the modules are listed on their own pages: series L, flood lamp SFL and Spot P. They are available in five wavelengths: 365, 385, 395, 405 and 450 nm.