Seimens plc's

Hi people,

I know I have asked this before but I still need spacifics, I have gone through the whole seimens manuals and also looked on there Net site.

I am trying to find out there "special functions" in relation to any plc they make, I'm not picky anymore. They dont seem to bost much about it thats for sure.

Please help me I'm really stuck on this one!!!

A dictionary definition of special is :- unusual or superior: distinct, different, unusual, or superior in comparison to others of the same kind

Going by the above defintion I believe it would be difficult to list any functions on the Siemens range of PLC's that could be classed as special.

Still I will try to help you. If you would just like a list of functions availiable on S7 200's 300's and 400 PLC's, as appropriate for each range, then I might be able to help you. I take it that you would like programming functions i.e maths functions, such as equal to, greater than etc.

If this is what you want then I will email a list to you

I am also curious to know what course you are on.

Paul

Hi Paul,

I am in my final year of an HNC in engineering,

I reolise that special is very open ended and that eveyone has thier onw special functions this is why I thought I would use seimens as an example. For some reoson my email doesnt work properly at the moment even though this does, but you can try it anyway I will send it to you in a personal note if you are still willing to help.

Cindy,

How many posts is it going to take before you understand that the definition of 'special' is up to the person who wrote the test question?

Here's a suggestion for you. By now you should know the basic things that PLCs do. Go through the list of instructions supported by the PLC and pick the one that seems to you to be least connected to the basic functionality.

IM<HO, the basic instructions include anything related to Boolean logic, Timers, Counters, Math functions, and comparisons. Functionality beyond that such as PID, Shift registers, FIFO, LIFO, drum sequencers can be considered to be 'special' or 'advanced'.

Another approach you might take is to compare the functions offered on several different brands and models. Those functions offered on the fewest models of PLC could be considered 'special'.

I have a request to make of you. Once you get through this course, and have a little more time available, could you educate us Yanks on the logistics of these HNC courses. Are they offered in a traditional classroom setting where an instructor lectures on the topic of the day and the students struggle to take notes and try to understand? Is there a physical lab where you can practice? Is there ever a session where you have an opportunity to ask questions? What is the purpose of these courses?

For the most part, those of us who make our living practicing the craft of industrial automation, don't see the PLC portion as being of much use in the real world. Please help us to find out if our perception is accurate, or if it's biased by the types of questions we get asked.

Cindy
try reasearching the FM 355 Controller Module – i ran into this one during the week, its quite interesting. the controller will continue to run in"backup mode" even when the CPU fails or profibus connection if in remote I/O. I spoke with seimens tech support and they have only two people that deal with these "special" modules. worth a look!

safety plc

uh hum...?
I may be a little off here?
my company started using the safety plc for a project.
how can i find any information on this.
(no one wants to share the books)

Are you refering to the Siemens S7-400 Failsafe plc?http://www.sea.siemens.com/automat/product/plc/s74f/aus74fov.html

A-B also makes safety PLCs called the GuardPLC1200 and GuardPLC2000. Links can be found right on the A-B home page.

http://www.ab.com

Specify what brand of PLC and you'll find our help to be much more specific.....and useful.

OG

There is one other safety PLC that I know of. PILZ
Modicon also make a safety module for on of there PLCs.
Regards Alan

Cindy

If you email me with the exact question that your tutor asked I will try to assist you. As someone who went through all this many years ago I understand what you are possibly going through.
Tutors (in my experience) like to see that you are capable of researching a subject which is the reason why they set these vague, open answer questions.

To answer Steve Bailey's question, when I went through college as an electrical engineering apprentice, the lecturer did just stand at the front of the class and waffle on while you sat there struggling to make notes. Some of the work was backed up by lab work.

In defense of a lot of the lecturers I had the pleasure of being taught by, the majority were more than willing to assist you after class if there was a particular point that you did not understand.

PLucas / Cindy:

At colleges here in the States, the profs have a quaint practice called "office hours". During these (ir)regualarly scheduled times, the prof is supposed to be in his/her office, available to the students to ask any damnfool questions.

It takes some students a while (particularly engineering students, who have an ego which tells them "I'm smart - I can figure this out by myself") to realize that this is a temendous opportunity for learning and clarifaction of homeowrk quesstions.

I've seen where some profs will go so far sa to guide you through any point/question - even homework questions - that you just can't grasp.

Most profs spend "office hours" being bored (grading papers, reading journals) and truly welcome a student seeking knowledge.

I only know how my own corner of the universe works. Do they have such a custom in the UK? If so, why ddin't/aren't you taking advantage of it?

Special Functions are used in the Siemens TI-505 series of processors. Per the TI505 programming manual special functions are defined as per the following


A Special Function program consists of a set of high-level, statement-driven
programming instructions that can be called from loops, analog alarms, or
from the RLL program, much like a GOSUB subroutine in a BASIC
program or a procedure in a C language program. Typically, the types of
operations that you execute within an SF program either cannot be done
with the RLL instruction set, or they involve complex RLL programming.
Such operations include floating point math, If/Then conditional
statements, table transfers, data consolidation, etc.

Thanks to the nice guys

To everyone who did actually write something helpfull in a nice way, thankyou!!!.

Steve you have no ideah what I am going through on this course or my personal circumstances. Yes I do sit there in a class where the tutor doesn't even give lectures for you to get lost, he attempts to give some instruction to 17 students all asking for help at the same time, while a bunch of imigrants that can even speak the language are also trying to get his attention. I would have quit by now if I was in his shoes (in his defence. I do not have access to him or anyother tutor other than this 1 and half hours a week.

Steve you come across as a lecturer yourself!!!!

FM355

The 355 module i was refering to will continue to run a PID loop even when the cpu its attached to poops out. as long as you can keep 24v fed to it it will perform. i may have misunderstood Cindys question wh she was asking for "special" peices of a siemens plc.
Good Luck Cindy!

Think "Guest" go it right , try http://www.sea.siemens.com/automat/product/plc/505/au505man.html

Go to PDF Maunual "TISOFT2 Rel 6.3 thru 7.1" check out chapter 8.8