ab selection rules

govoni

Member
Join Date
Jan 2009
Location
USA
Posts
6
HI
I have my first automation project as a contractor and its AB! I am trying to spec the hardware.
I/O count is:

  • 32 DI
  • 32 DO
  • 30 AI (thermocouple)
  • 6 AI (RTD PT100)
  • 16 AI (FROM 0-5VDC)
NO PID LOOPS SYSTEM ALL AI WORK AS ALARM ONLY VIEWED BY PANEL VIEW
questions:
1) What IS THE BEST ECONOMICAL SPECS .
2) WHERE I CAN FOUND SELECTION RULE THAT TELL ME controller(COUNT,PERFORMANCE,PID...etc) limitation.

Thanks in advance.
 
govoni,

your profile indicates that this is homework, but you say you are a contractor.

my question is:
1. are you doing the electrical design as well and if so
are you familiar with the nec, nfpa79, nfpa 496, nfpa40
2. are you doing the programming?
3. what is the classification of the area where the machine
is going? class 1, class 2, class 3, general purpose?

We use slc 500's - company standard.
we also have (1) compact logix and everyone hates it so far.

regards,
james
 
As we move forward, everything will be either ControlLogix or CompactLogix, depending on the project requirements.


Govoni, you either need to get real comfortable with Allen-Bradley's website, or develop a good working relationship with you local AB rep.
 
Can you explane why you hate the CompactLogix ?
I'm replacing all our PLC5's by CompactLogix L35E and I love them...

Jack

I would venture to guess it is due to one of two reasons:

1. The OEM/Integrator did a poor programming job, so the program is unorganized, tags are unorganized and inconsistent, and descriptions and documentation is poor. Certainly reasonable to believe that would leave a sour taste in their mouth (I've been there....)

2. Internal lack of knowledge of the Logix platform and or CHANGE.
 
The reasons we dislike the logix 5000 platform.

1. tag based.
how do you debug a plc program when the printout is tag
based and the i/o structure of the electrical prints is
based on line numbers / plc I/O.

2. yes, its new and will definitely take time to literally
learn the new system of programming.

3. so far, no one can debug the system, even with a laptop
due to item #1 and i get called at all hours of the night
to come fix the problem.

so i guess the verdict is still out, but for now its thumbs down.

regards,
james
 
I don't understand. if your people can't debug the system. you should consider your tag idenitification. If they understand I:001/00 then convert to tag: I_001_00. Don't let them be confused by (Local.Data.I)etc.
 
The reasons we dislike the logix 5000 platform.

1. tag based.
how do you debug a plc program when the printout is tag
based and the i/o structure of the electrical prints is
based on line numbers / plc I/O.

2. yes, its new and will definitely take time to literally
learn the new system of programming.

3. so far, no one can debug the system, even with a laptop
due to item #1 and i get called at all hours of the night
to come fix the problem.

so i guess the verdict is still out, but for now its thumbs down.

regards,
james

So it isn't the platform itself, it's the poor integration of the platform and/or poor documentation of the electrical prints.
 
So it isn't the platform itself, it's the poor integration of the platform and/or poor documentation of the electrical prints.

I started out hating tags, grew to love them. One trick is to use the device name on the prints (PIT-1 Lube system pressure) and in the program tag name.
 
I agree with Tom. The trick we always used was to id devices by output or input location. ie: PE101 = slot 1 input 1 and M300 = slot 3 output 0 That way with proper field id you knew where each device was located in program. You didn't need print to cross reference for location in program.
 
I like to use alias tags (to real I/O) and in the tag description, call out the device name as its detailed on the drawings. So, you'll have the real I/O address right above the contact, above that the tag used in the program, and in the description how to find the device in the drawings.
 
I like to use alias tags (to real I/O) and in the tag description, call out the device name as its detailed on the drawings. So, you'll have the real I/O address right above the contact, above that the tag used in the program, and in the description how to find the device in the drawings.

I do exactly the same, but it seems that we get a little bit out of the topic.....
 
I dont see how anyone could hate the rs5000 softeware platform. IMHO, it is by far the best programming package, and the easiest to troubleshoot if implemented correctly.
 

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