Reliability Since the Design Phase

(Spanish Version)

These are some examples of how reliability factors are incorporated to Indicart's products during their design:

Protection against electrostatic-discharges

The electrostatic-discharges were always the main cause of failure for electronic equipment.

The human body is commonly charged with electric energy when it is in contact with certain materials that were under friction, like clothes, chairs and rugs. This energy discharges through the ambient's humidity or through our shoes, and most of the times we don't notice it, although sometimes it discharges abruptly when we touch a faucet some other metallic part making a small spark that can be very annoying.

The problem arises when this energy is discharged through an electronic component. This can occur if we touch the enclosure or a connector of a product that is not protected. Maybe the discharge is unnoticed by us but lethal to the equipment.

All of Indicart's products are fully protected against electrostatic discharges. On the input/output lines we place state-of-the-art semiconductors that are capable of absorbing discharges that largely exceed the maximums considered possible on quality standards. And the enclosures are mostly metallic and grounded, and the acrylic front is specified so as to have enough isolation to prevent discharges through it.

Protection against voltage spikes in the power line

The electric outlets' provision is not perfect. The specified voltage (220 volts, 110 or whatever corresponds to your country) is what we expect to have but in reality this voltage varies. There even are short spikes of much higher voltages from time to time, specially if the outlet's line has some electromechanical device, such as an elevator, connected. It is normal for the mains' voltage to experience ten spikes of a thousand volts per year!

An electronic device that claims to be reliable must be protected against these voltage spikes. The Indicart signs are. Like with the issue of electrostatic discharges, this protection is achieved with the use of state-of-the-art semiconductors.

Mechanisms to guarantee a continuos operation

The imperfections in the power line are not only spikes; sometimes the supply is interrupted. If it occurs for only a fraction of a second we might only notice a subtle blinking in lamps and we don't care about it, but it can affect the operation of an electronic device that was not designed with this in mind. A digital device may stop working. In the case of an electronic sign, this might damage the L.E.D.s.


This can't happen with an Indicart. If the power interruption is long enough the same circuit that guarantees a reliable turn-on of the sign will reset it, which means turn it on again. If the interruption is short the program that controls the sign wouldn't be affected because it was designed robustly and because the sign's hardware includes a watch-dog circuit that will reset the controller if it is necessary.

Long-life power supplies

The power supply is the circuit that converts the power-line's energy to what an electronic system needs. All common supplies use aluminum electrolytic capacitors. The disadvantage for this kind of capacitor is a limited useful life, but it is the only one that comforms to the requirements for this application.

With electronic signs, an kind of product that may be constantly on, this component is critical for reliability. That is why Indicart's products include long-life capacitors and supplies are design so as to minimize their worn-out. Concern is also put in specifying the other components with responsibility and we even carry redundant processes that improve reliability such as reforming the electrolytic

So we can assure that, after years of operation, an Indicart will be working perfectly well while others might already have needed more than one service.

Memories with no batteries

Indicart signs use EEPROM memories. This kind of memory is capable of keeping its content with no kind of power applied. The state-of-the-art of EEPROM technology is in a growing state, some years ago it would not be viable to use an EEPROM for these kinds of applications. What was done was using an ordinary memory and adding a battery to provide some power for it when the sign was unplugged.

This has a problem, which is that batteries have a limited life-time. The ones that were used in most cases were the same that are used on PC motherboards and their approximate life-time is of four years. If you had a PC for more than four years you might have had trouble with the machine's time-of-day clock loosing the time because of this. The same failure is typical in electronic signs with batteries but it implies continuos losses of the messages that were programmed.

Surely other manufacturers will also solve this problem by incorporating EEPROM technology into their products. In the case of a sign where messages can be entered by keyboard they only will if they have our commitment towards quality and work as much as we did to suit the EEPROM technology to this application with the sole objective of achieving the highest possible reliability.