|
Understanding 4 to 20 milliamp Loops
Robert J. Scoff, P.E.
Overview
4 to 20 milliamp loops are
found in many places in the industrial world. If we work on control circuits,
sooner or later we will get a chance to see one. At first glance, they might
seem to be confusing and complicated. However, if we really look at what they
are and how they are connected, we will see that they are really pretty simple.
Thus, the purpose of this course is to help engineers see how simple they really
are. Then when you get a chance to either apply them or troubleshoot them, you
will easily be able to do your job. Since 4 to 20 milliamp loops are all direct
current, no understanding of alternating current with its vectors and phase
angles is necessary. The mathematics is simply add, subtract, multiply, and
divide. The calculations that are necessary to work this course can be done
with a pencil and paper.
This course is designed so
that engineers of any discipline can benefit from it. There is very little
electrical theory involved. It is more of a practical application of some
simple electrical principles. After taking this course, any engineer will be
able to work with 4 to 20 milliamp loops, and, if the proper instrumentation is
available, calibrate them.
The student must take a
multiple choice quiz consisting of 20 questions at the end of the course to
obtain PDH credits. It is my intention that the material presented in this
course will help the students become better versed in applying and understanding
4 to 20 ma current loop controls.
Specific Knowledge or Skill Attained
This
course aims at teaching the following specific skills and knowledge:
- What
are 4 to 20 milliamp loops?
- When
are 4 to 20 Milliamp loops used?
- Why
are 4 to 20 milliamp used?
- How
are 4 to 20 milliamp used?
- Where
are 4 to 20 milliamp loops used?
- And
finally, who uses them?
Course
Click on the following PDF attachment and review the document
"Understanding 4 to 20 milliamp Loops" prior to taking
a quiz for credit.
Understanding 4 to 20 milliamp Loops (154 KB)
Having Trouble Downloading the PDF File?
Right click on the link. Select "Save Target As..."
Then save on your desktop. To view the file, double click the icon on your
desktop and return to this page to take the quiz.
You may need Acrobat Reader to view this document.
Click on the link below to download a free copy of Acrobat Reader.
To obtain PDH credits for this course, you will need to take a quiz for
credit. Click on the link below.
(To take the quiz,
your web browser must be set to accept cookies. See how to
check your cookie settings.)
|
