What is require for PLC Programming?

Answer Posted / carl_ellis

You'd all fail my class for failure to mention these three
things:

- A project scope document
What is to be controlled, alarmed, displayed and
communicated? What is the purpose and what are the
functional criteria for the project? What are requirements
for acceptance of the project? What limits the
dreaded 'scope creep' ("Oh, I thought it would
include . . ." or "we need to add this")

I tell my pupils that the homework problem description
constitutes the 'scope' for purposes of a class, but in the
real world it might be a 400 page scope document, but
whatever form it takes, they should never accept a verbal
description, but should insist on a written document,
because that's what defines whether their programming meets
the standard of having been done properly.

- An I/O list is absolutely essential. What are the
inputs, what are the outputs?

- The PLC's documentation
Nobody remembers all the little syntax or functional
details. It's up to the programmer to look this stuff up
because in the real world, there's no 'teacher' to answer
the question about the timer's minimum interval.

Those three things are essential. Lack of any of the 3
constitutes negligence.

Lack of mention of any of the 3 ?in the 5 answers already
posted tells me your instructors are book people, not real
world PLC programmers.

------------------------------

Carl Ellis, Measure First

Is This Answer Correct ?    2 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

i want formula for flow control.am doing project in flow control using orifice . i know value of the flow level(Q) . upstream(p1) pressure, orifice diameter(Do) , pipe diameter(Di) and oil viscosity(Vi) how can i calculate downstream pressure

1446


Can please tell mi about SIOS, PRM, SERVER, and what is the diference between PIN LAN, PCS LAN,APC Server, and please send the Doc if possible for referance,mail id patil_amit17@yahoo.com

1447


installation process of orifice,a question asked for confusion creation in interview by BARC 1.if orifice is tightly fitted with pipe ,it will act like venturi 2.if orifice is left hanging in between liquid it will not create the pressure difference exactly,

1665


In turbine, what does term CDP, NI, NH, HSSOC, means

2199


Can anyone convert a 5/2 way or 3/2 way valve into an ISO valve?

480






How is automatic reference junction compensation carried out in temperature recorders?

641


What is the start up procedure of desalter

3040


What is critcal speed. what is resonant frequency. why we want to cross crtcal speed on higher RPM (early).

1675


i have been asked by QAFCO to appear for interview for thy post of Instrument Designer(INTOOLS)..i m engineering graduate with 5 years exp. in design engineering.Will this job profile suit me??i need all ur help n suggestions for thy same?

1794


what will the sending unit in the fuel gauge utilizes?

1467


Draw a complete P&ID of a flow suction tank indicating all control & protection equipment. Indicate all its inlets and outlets. Explain the controls for this system

1102


Actual using of tube bender to bend 2 opposite 90 deg at correct measurement center to center of tubing.

1497


please send me the inteview questions in IOCL

1763


How do bending tubing provide better measurement than using tubing fittings such as elbows?

1484


how to calibrate load cell

2317