S7 : where to start?

Doug-P

Member
Doug-P
Join Date
Jun 2003
Location
Pa
Posts
1,248
I feel I'm at the absolute bottom of a steep learning curve.
I've dealt with mostly A-B products for years (PLC-2, PLC-3, SLC, a brush with CLX, some Automation Direct). It's all very familiar and comfortable.

Lately though, I've had to deal with our hybrid cranes which are controlled by a Siemens S7 300. Just navigating the program is an Easter egg hunt. It seems very clunky compared to RSLogix. I downloaded some S7 manuals to try to get some familiarity with this system - LAD and STL. I discovered I need to get much more elementary - data blocks?, RLO?, :confused:

Can someone suggest some beginner level publications? Somthing like:

Introduction.
To.
Accumulator 1.

Thanks

p.s. No manuals (that I've seen) were provided by the contractor. Lovely, eh?
 
Last edited:
 
Last edited:
Thanks, Moggie! Looks like I'll be doing some printing (I'm old school that way).
 
L D[AR2 said:
Do you have access to a plc that you can experiment with, or failing that, PLCSIM?
Click to expand...

I do. It'll take a bit of doing tho', there's no local(?) I/O, everything is Profibus, something else that's new to me. The main physical I/O is all WAGO modules - a mix of digital and analog I/O. There's also an OP73 for messages/operator input, a Unidrive for the hoist control, and an encoder (absolute, IIRC) for hoist position. Excluding the last three items I can cobble together a power supply, the processor and some of our spare WAGO parts to get a basic system running.

I cannot say whether PLCSIM is available or not. If it's a part of the SIMATIC package it may be there.

Thanks for the reply.
 
I'd start with the powered up CPU and add the I/O later. Which specific model CPU do you have?
 
L D[AR2 said:
I'd start with the powered up CPU and add the I/O later. Which specific model CPU do you have?
Click to expand...
I don't have it in front of me but I think it's a 300. I won't be able to check for sure 'til Sunday night. I'll post the part number here when I find out.
 
Doug-P said:
I don't have it in front of me but I think it's a 300. I won't be able to check for sure 'til Sunday night. I'll post the part number here when I find out.
Click to expand...
300 is the series (think of it as a ControlLogix with modules).
400 is also a series but the hardware is huge compared to the 300 series (think of a PLC 5 series hardware).
CPUs come in the numbering scheme, 312, 314, 315, etc.
Then you have the 315-2DP or 315 PN/DP and such.
These are options, 2 DP is dual profibus connectors (and access points for you for that matter).
PN is Profinet similar to industrial Ethernet
There's MPI and such but for now I'd worry about the model and take it from there.
As far as the rest of the part number goes denotes the work memory and such, not imoprtant for now.
Keep in mind that newer CPUs WILL NOT work without an MMC (Memory Card).
 
I checked the processor. It's a 315-2 DP

I also printed out the 'Getting Started' manual from the link moggie provided (y) and managed to enter the first elementary programs using LAD. All went well until I got to the function block section. I managed to create the block and open it but never saw the symbol/variable table, which is supposed to appear above the LAD display. So, I gather that function blocks are analogous to subroutines in RSLogix, correct?

I havent' yet looked for the simulator.
 
Doug-P said:
I checked the processor. It's a 315-2 DP

I also printed out the 'Getting Started' manual from the link moggie provided (y) and managed to enter the first elementary programs using LAD. All went well until I got to the function block section. I managed to create the block and open it but never saw the symbol/variable table, which is supposed to appear above the LAD display. So, I gather that function blocks are analogous to subroutines in RSLogix, correct?

I havent' yet looked for the simulator.
Click to expand...
Function Blocks are Function Blocks as in the AB world Function Blocks.
They are NOT subroutines.
You can call a Function Block from OB1 or any other FC.
 
Doug-P said:
I managed to create the block and open it but never saw the symbol/variable table, which is supposed to appear above the LAD display.
Click to expand...

The section you are looking for is most likely hidden due to the window arrangement - move your mouse over the dividing line and drag it down to reveal the Interface Declaration.

sss.JPG
 
L D[AR2 said:
The section you are looking for is most likely hidden due to the window arrangement - move your mouse over the dividing line and drag it down to reveal the Interface Declaration.
Click to expand...
Yes, I stumbled on this by clicking on the window maximize button in the upper right. I was then able to enter the variable names and value as mentioned in the tutorial.
 

Similar Topics

N
OT : where would I start learning more control theory on my own?
I am currently enrolled in a 3-year technical program at a collegiate institution. This is my last year. I also work in a co-op fashion for an...
Replies
12
Views
4,707
duckman
D
D
where to start with Siemens S7-200 CPU-226
Its a S7-200 part # 6ES7 216-2BD23-0XB0 A customer sent me one of these to extract the program out of. I have zero experience with Siemens S7...
Replies
5
Views
2,224
geniusintraining
geniusintraining
V
PLC Training, where do I start??
I am currently a senior in a vocational school, for the past year I’ve been working on RSLogix and really found a passion for it. I want to become...
Replies
5
Views
1,910
JaxGTO
JaxGTO
C
Looking to get a Controls Engineering degree, where do I start?
I've been doing control systems design and PLC/HMI programming for about 3 years at my current company and I've really come to love it. However...
2
Replies
17
Views
4,156
Sydney
S
V
Where to start as a PLC NOOB!?
Hi all, noobie here to plctalk! I currently work as a robot programmer/operator, I program a ABB IRC5.15 linishing/polishing robot and a CLOOS...
Replies
10
Views
3,319
Veets
V
Back
Top Bottom