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Product category: Logic Controllers, Timers and Relays
News Release from: Panasonic Electric Works UK | Subject: Matsushita timers
Edited by the Engineeringtalk Editorial Team on 05 March 2007

The changing face of industrial timers

Modern timers have been designed to allow clear defined operation but with a range of auxiliary circuits to offer the user a wide range of functions to give as much flexibility as possible.

The ubiquitous timer is often overlooked in the complexity of manufacturing systems using programmable logic controllers, human machine interface devices and smart systems Yet the product has undergone a high level of technical change when compared with similar products available only a few years ago

It could be argued that many on-panel systems contain timer functions as a standard, such as the PLC, and that these prove perfectly acceptable.

Of course this is true for many applications, at least until a timing period or function has to be altered, especially during a trial or set-up period.

To change a PLC timing function some knowledge of the program is usually required along with the requirement to take the out of running mode during the time alteration.

Timers on the other hand can be continuously varied by even the most basic of operators so making adjustments very simple to achieve and monitor.

Conversely an HMI can offer an access to a timer function but this can be a costly alternative and certainly would not be an economic solution to a single application low usage timing function.

Modern timers have been designed to allow clear defined operation but with a range of auxiliary circuits to offer the user a wide range of functions to give as much flexibility as possible.

However the basic timers usually consist of an old style cradle relay with a timing circuit and analogue dial set.

A good example is that of the Matsushita S1DX timer.

This is a four-changeover-contact 5A timer that by selection of a suitable model can offer various timing periods ranging from 0.05s to 3h.

This is aimed at the user that requires a reliable timer at the lowest cost so these devices are designed with the minimum of components and auxiliary functions and their ubiquitous use indicates the popularity of such product.

Of course these basic timers have limitations, not least is that they usually only offer single timing ranges or are restricted to a particular supply voltage.

One obvious problem leading from this lack of versatility with the basic types of timer is that many individual units and part numbers must be stocked if a wide variation in time is required or different supply voltages needed.

In many applications this does not cause any great difficulty to the end user but, as in all electronic markets, the general rule is greater function for a lower price.

For some applications the fact that they can only indicate the total timing period and cannot give an indication of time remaining before operation can cause a problem in analysing a more complex timing cycle.

With the advent of low cost digital circuitry, and to give customers a universal option, manufacturers introduced digital timers based on the DIN 48mm standard case.

Ideal for panel mounting, since they share the standard sizing with a wide range of complimentary product such as counters and temperature displays, the 48mm case includes brackets and orientation slots to help with mounting difficulties.

These timers are set by a number of front mounted buttons and offer a display (originally LED but in later models this was superseded by the more power efficient LCD) that can indicate the timing period set, time remaining as well as auxiliary features such as contact condition or mode selection.

Because these types of timer are using IC processing and bistable relay actions they can offer a very wide range of timing functions including power on, signal on/off, pulse, cycling and totalising delays in addition to having a 24V DC to 240V AC supply tolerance.

Matsushita LT48 timers demonstrate the usability of this type of product allowing users to stock just one timer to cover all eventualities.

The addition of clip fronts has allowed aesthetic appeal so that the timer can be matched into the surrounding panel cover.

This helps the timer to appear as a bespoke unit rather than a standard catalogue item.

Although the digital timers offer practically all the required functions within a single package there is a demand for a hybrid timer.

This takes all the benefits of the digital unit but replaces the LCD with an analogue dial equivalent.

This is perceived as being more user friendly because as in the case of the basic timer the dial setting allows a 'hands on feel' with all the time settings and mode functions being displayed in an analogue format.

Matsushita introduced the PM4S timer to cover this requirement and the increasing sales show this to be a popular addition to the existing ranges.

Due to its popularity the DIN 48mm package is probably the most used size format for timers.

However they can be offered in many other package size.

A widely used 24mm slim-line timer allows the best space/size ratio should DIN rail mounting be required.

Industrialised screw terminals can make for easier wiring being mounted on the top and bottom of the front case rather than at the rear as is the case with other types on timer.

With a higher current switching capability than their 48mm counterparts 24mm slim line timers can eliminate the need for an intermediate relay should direct control of motor or inductive loads be required.

Matsushita's PM5 timer range offers just four types to cover all applications with IP40 construction allowing use within the majority of industrial applications.

The once accepted 72mm case has now been replaced by smaller formats.

The advantage of the larger size was the increase in the clarity of the display.

However the push to reduce panel size and the accompanying limitations in panel space available and by the fact that it is possible to utilise other display devices, such as small runner displays or HMIs, to magnify any numerics that can not be clearly seen on a 48mm unit.

The future for timers is likely to see the inclusion of more functions and auxiliary features combined with a lowering of price.

Although other factory automation products contain timing functions it would be difficult to see the demise of the standard panel timer but it would be credible to expect the end user to request a combined timer/counter or hour meter function into a standard unit.

However it should be remembered that miniaturisation, although perfectly possible, can not be taken too far as a human operator's hand still has to provide the input information and this does have finite limits.

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