Company Profile

SATET provides industries and engineers with extensively researched, well written, and reasonably priced software

tools for use to its customers across world, SATET software tools are written for users who need electronic data

collection and digitalization of workflow. SATET is a supplier of real-time data collection software using cross

platform tools, .Net, Android IOS and Java platforms.

SPC Tools

Help us to identify the source of process problems, define a process’s capability to meet a customer

requirement, and assist with other insights

Control charts typically display the limits that statistical variability can explain as normal. If your process is

performing within these limits, it is said to be in control; if not, it is out of control.

Nelson Rules

How do you judge when a process is out of control? By plotting a control chart of the output of a process, it is

possible to spot special or unnatural causes of variability and indications that the process is drifting. Drifting is

defined by the mean or range of the variation changing as the process is running. The most common indication of

change is a point falling outside of the control limits, but other tests for process instability are also valuable.

Zones In Control Charts

Many of the standard rules examine points based on zones. The area between each control limit and the centerline is divided

into thirds. The third closest to the centerline is referred to as Zone A, the next third is Zone B, and the third closest to the

control limits is Zone C. Note that there are two of each of the Zones, one upper and one lower.

Zone A is also referred to as the “3-sigma zone”, Zone B is the “2-sigma zone”, and Zone C is the “1-sigma zone”. These sigma

zone terms are appropriate only when 3-sigma is used for the control limits.

Sigma is the Greek letter for s and is used in this context to denote the spread of data.

Standard control limits are located 3 sigma away from the average or centerline of the chart. The centerline is also called

the control line. These are called 3 sigma limits or 3 sigma zones. The distance from the centerline to the control limits can be

divided into 3 equal parts of one sigma each.

Statistical theory tell us that in normal data dispersion, we can expect the following percentages of data to be included within

the sigma:

 1 sigma – 68.3%

 2 sigma – 95.5%

 3 sigma – 99.7%

We can expect 99.7% of the process outcomes to be within the 3-sigma control limits.

Contact Information

Telephone –  +1 919-6374407

FAX – Please send any FAX as a pdf file attached to an email – send to contact@satet.us

Postal address – 1100 Augusta Drive, NC 27302 USA

All images on this web site, in demo programs downloadable from this web site, and in trial software downloadable

from this web site, are copyright SATET LLC, and cannot be used by others without our expressed permission.