Question about scheme's terminology

Hello guys,

I want to ask question about terminology used in process engineering in certain countries.

Recently, I had opportunity to read about regulations schemes and there were blocks labeled PT1, PT2 and PT3. As far as I could conclude, PT1 block represents first order linear filter. It has one parameter in seconds, so I figure out it must be block whose transfer function is: G(s) = 1/(Ts+1), or linear differential equation: T*dy/dt+y = x, where „x“ is input and „y“ is output from the block. Regulation scheme was on German and I'm interested to know whether this is usual scheme terminology in process control in Germany or what?

Have you ever heard about PT filters? Why PT?

Thanks

You got me.

I haven't heard of PT filters either.

seems someone is doing first year degree text here!
yes that transfer function can be used to represent a passive filter, although this would be in its most basic form and many other parameters need to be considered before developing a correct model. Fuzzy logic is also an interesting control system technique, read Ken Duttons thesis on this if you have genuine interest!

http://en.wikipedia.org/wiki/Electronic_filter

I had the laziest Professor of all time in school. Anything he wanted to teach he just plugged in the laptop, opened wikipedia and found the info.

Thank you Peter for your reply!
@ryan and scot:
You obviously understand my question wrong. Question is about scheme terminology, I cant open subsystem mask to see what's under this famous PT1, so I think it's passive linear first order filter.
Have you heard or seen blocks with labels PT1, PT2 or PT3 on any process control diagram? If not, answer is simply "no".

You probably using PCS7- the PT1 filter is pretty common with Siemens- Here's a portion of the help file-

Description of PT1_P

Object name (type + number)
FB 51

Calling OBs
The OB in which you install the block (for example OB 32).
Function
The block operates in accordance with the equation:
v(s) = 1 / (TM_LAG * s +1) * u(s)
Operating principle
The input signal U is passed to the output V in accordance with the time constant TM_LAG.
The STOP_RES input can be used:
1. To stop the calculation process with "1". The output value remains unchanged for the period.
2. To reset the output (V = U) at a negative edge 1 ®? 0.

Jump response of the PTI_P
Error handling
The parameter setting TM_LAG = 0 is allowed and means no delay, i.e. V = U. Negative values for TM_LAG are regarded as parameter errors and are acknowledged with QERR = TRUE.

So Pandiani is right. PT is just a simple first order low pass filter.

PT, yet another terminology to confuse us.
This doesn't answer Pandiani's second question.

Why PT?

Click to expand...

I didnt realize this was a test, I simply responded back with the help file.

JRW said:

I didnt realize this was a test, I simply responded back with the help file.

Click to expand...

Everything is a test, just beware !

When the missus ask me a question my first thought is "Is it a trick question"?

Hey guys,

I just figured we came to this forum (and others) to escape the test traps devised by our spouses and bosses.
This was supposed to be a place where we could open up, without fear of reprisals or evaluation, wasn't it?
Daniel Chartier

I am just curious like Pandiani

How does PT translate into low pass filter? Is this a German thing or a Siemens thing to confuse the rest of us and waste our time?

Hehe, I found more information. PT1 is actually first order delay element. It has only one parameter to configure under it's parameter mask and that's delay time. So, I assumed right. PT2 is actually cascade connection of two PT1. It's a software blcok used in Siemens Teleperm. Why PT and if it is acronym for something I simply cannot even guess. Maybe P stands for passive but only guys from Siemens can answer this...

It seems that PT1 is common in German literature. i have just found online lectures from University in Bochum.
http://www.atp.ruhr-uni-bochum.de/rt1/syscontrol/node28.html