Let us see some examples... 

For example in a machine, it will be convenient that in all types of instruments: pressure gauges, thermometers, etc. to mark lines or areas that indicate the ranges of normal operation and the ranges of risk.  Also analogical meters should be rotated them so that the pressure, temperature or correct reading is in the position of "the 12:00" (top). We can paint or stick color film indicating: Correct or good (green) reading; Yellow-caution; Red-danger, either if there is risk in the operation for the operator, the machine or that the product can be damaged or have poor quality. In the event of digital indicators, we should make sure to have a clear sign indicating the correct readings.  There should also exist a clear indication of what we are measuring in that instrument.  

Visual systems should also be applied to facilitate the inspection and the maintenance. For example, if in the verification list the point number 7 is a belts transmission, the corresponding belt-cover will have a number 7 clearly marked. This can be inside a square or inside a circle, this will tell us that the number is part of a check list or report.    

And speaking of belt-covers: It is very convenient to have a clear mark that tells us what type of belts and the number of them that are required. It is also helpful to have an arrow that indicates the correct rotation. This is particularly useful when a major repair is done in which it is necessary to change or to disconnect and to reconnect a motor or electric elements. Rotation arrows should be present in All Rotating Devices. Let us remember that there are many machines that can suffer serious damage if they work in the wrong rotation.    

Another aspect of great advantage is that the grease fittings and points of lubrication also be clearly identified. It is not only important to know where they are, but what type of lubricant they should be supplied with. In many cases there may be a color code for this purpose. With grease fittings, it is advisable to use covers for them. Besides helping (with their color) to identify them, the covers will avoid the contamination of bearings and lubricated surfaces.   

The same consideration for piping: standard codes exist and also conventional codes. The important issue is that all the people, who are involved with the equipment in its operation and maintenance, very clearly understand the code meaning. In most of the cases we should try to have good quality quick release plugs, which generally facilitate the maintenance operations and the tooling changes (setups), etc. Use the color codes and also clear signs and arrows showing the direction of flow on the pipes.  

Another practical application of visual systems is the use of pilot lights that allow observing from the distance some problem with an equipment or system.   

Also very important among these visual systems will be the visual board of each machine. This serves so that at all times, any person can see the performance of the equipment, name and if possible picture of the equipment’s operator(s) or "proprietors", maintenance details, operation graphics, indexes of productivity, reports and verification lists for operations of autonomous maintenance in charge of the operator "in their own words."   

In support of 5Ss, an important issue is the marking of lines and location areas on the floor. Generally, using adhesive tapes, you will be able to conserve the order and organization of the workspace. Again, this allows all persons to understand the correct use of the area.   

There is no limit for these visual supports. Let us make use, as it was said before, of the creativity of the whole personnel. I have found some with very explanatory drawings. We can even organize competitions on diverse warnings in the plant.