Frequently asked questions
LVD2014/35EU Low Voltage Directive
The EU rolls out new rules to prevent unfair competition, as of April 20 2016 there is a new version of the Low Voltage Directive (LVD). This new law effects electrical equipment designed for use with a voltage rating of between 50 and 1000 V for alternating current and between 75 and 1500 V for direct current, other than the certain specified equipment. This directive is designed to enhance safety and prevent unfair competition in the market, so is likely to be good news for us that manufacture equipment in the EU and bad for companies that import cheap products from the far east. Please clip below to see some of the key points:
Do I need a Risk Assessment?
The short answer is yes: “If you are an employer or self-employed. It is a legal requirement for every employer and self-employed person to make an assessment of the health and safety risks arising out of their work. The purpose of the assessment is to identify what needs to be done to control health and safety risks. Regulation 3 of the Management of Health and Safety at Work Regulations 1999.” (From the Health and Safety Executive Website - http://www.hse.gov.uk/risk/faq.htm#q8 ). Written by Businesswise Systems Ltd
What is a ground loop?
Motion controllers and automation systems use sensitive analogue signals. To protect these analogue signals from being influenced by other signals such as hum and whistle in the case of audio signals, an outer connection which is made out of foil or braided wire is often included around the cable or groups of conductors. This is commonly called a shield and its purpose is to provide a barrier reducing the amount of noise or other signals often called "crosstalk" that effect sensitive signals.However if current is allowed to flow in the screen it can actually make things worse therefore grounding a screen at both ends is not recommended this is called a ground loop
Motor Current Torque and power
Engineers often get confused between motor ratings and the amount of power they need to provide. In most cases the answer is that the capacity of the power supply can be considerably lower than the stall current.
What is a quadrature encoder?
There are a minimum of two outputs from an incremental encoder that form the distance measuring part of the output signal. These are the A and B signals. These two signals are 90 degrees out of phase with each other. The encoder therefore sends out two signals each of which has a rising and a falling edge, counting each edge therefore gives 4 electrical pulses to each mechanical pulse. which is what quadrature means, most rotary encoders are rate in pulses per rev (PPR) and the output gained from this is the PPR x 4, for example a 1000 PPR encoder gives 4000 electrical pulses. These signals are decoded to produce a count up pulse or a count down pulse.