PLC 5: Using O:000 and I:000 at the same time?

It would be helpful to know how many I/O points are in each module.

Post your .RSP file. Zip it first then post.

Can you post the picture as well ?

Here is the picture. It was 5MB. I think that Photobucket limits the size. Hopefully you can see it well enough


Click for larger image

Lakee911 said:

I received a photo of the rack and by comparing the height of the rack to the width, I have determined that it's a 16-slot chassis. Most likely it is the 1771-A4B.



It is populated as follows:

• Power Supply
• Processor 5/15
• 000: AC INPUT 120V -- Red Label
• 001: AC OUTPUT 12 TO 120V -- Orange Label
• 002: AC INPUT 120V -- Red Label
• 003: AC OUTPUT 12 TO 120V -- Orange Label
• 004: AC INPUT 120V -- Red Label
• 005: POWER CONTACT OUTPUT -- Orange Label
• 006: AC INPUT 120V -- Red Label
• 007: POWER CONTACT OUTPUT -- Orange Label
• 010: AC INPUT 120V -- Red Label
• 011: DC OUTPUT 10 TO 50V -- Green Label
• 012: ANALOG IN (12 BIT) -- Pink Label
• 013: DC OUTPUT 12-24V -- Green Label
• 014: ANALOG OUT -- Yellow Label
• Empty
• 015: POWER CONTACT OUTPUT -- Orange Label
• 016: POWER CONTACT OUTPUT -- Orange Label

I think my numbering is correct.



According to the program, I have usage within the following registers:

• O:000
• O:001
• O:002
• O:003
• O:004
• O:005
• O:007
• I:001
• I:002
• I:003
• I:004

So, which card goes to which register?

What registers are used for the analog input and outputs?

Click to expand...

OK,

Most likely scenario:

You have a 16-slot chassis set up for 2-slot addressing.

Minor edit to your list.

• Power Supply
• Processor 5/15
• 000: AC INPUT 120V -- Red Label
• 000: AC OUTPUT 12 TO 120V -- Orange Label
• 001: AC INPUT 120V -- Red Label
• 001: AC OUTPUT 12 TO 120V -- Orange Label
• 002: AC INPUT 120V -- Red Label
• 002: POWER CONTACT OUTPUT -- Orange Label
• 003: AC INPUT 120V -- Red Label
• 003: POWER CONTACT OUTPUT -- Orange Label
• 004: AC INPUT 120V -- Red Label
• 004: DC OUTPUT 10 TO 50V -- Green Label
• 005: ANALOG IN (12 BIT) -- Pink Label
• 005: DC OUTPUT 12-24V -- Green Label
• 006: ANALOG OUT -- Yellow Label
• Empty
• 007: POWER CONTACT OUTPUT -- Orange Label
• 007: POWER CONTACT OUTPUT -- Orange Label

This lines up pretty well with the address usage you show.
Your list above doesn't match exactly with the screen shots from first post, I'm trusting the screen shots. They show Inputs in groups 0,1,2,3,4 and outputs in groups 0,1,2,3,4,5,7.

The analog modules won't use any addresses in the I or O tables. They are accessed thru block transfers.

In most cases you have 16-point cards in input/output pairs. These will use all 16 bits in the input table and output table for that group. The analog modules can be considered empty slots as far as the input output tables are concerned. Group 7 has two output modules, they must each be 8-point modules for this to work.

A little history might help understand this.

2-slot addressing was the original setup using all 8-point cards. Very common in PLC2 systems. A 16-slot chassis is one logical rack.

Some people upgraded these systems with 16-point cards in input/output pairs to get more I/O but kept the 2-slot addressing. Pretty common on systems upgraded from PLC2 to PLC5.

For new systems using 16-point cards, 1-slot addressing is the norm. This means 16 input and 16 output bits per physical slot. It gives you freedom to place inputs and outputs as you see fit. A 16-slot chassis is 2 logical racks.

It is possible to upgrade a 1-slot system with 32-point cards keeping the 1-slot addressing. More input/output pairs.

The norm for 32-point cards in new installations is 1/2-slot addressing, which means 32 input bits and 32 output bits per physical slot. A 16-slot chassis is 4 logical racks.

Hope that helps some.

Just a general comment.

I was really surprised to find so much "almost correct" info in this thread.

mellis said:

....The analog modules won't use any addresses in the I or O tables. They are accessed thru block transfers....

....The analog modules can be considered empty slots as far as the input output tables are concerned.....

Click to expand...

Well, yes, but...

The bits in the I/O image for an analog module are used for the "Module Control Byte" - These bits make the Block Transfers work, don't use them for anything else. If you monitor them you will see them toggling when the block transfers are active.

Otherwise I totally concur with you, I was going to post the same result.

The only thing I could add is that when using 8-bit modules and 2-slot addressing, the left-hand module is the low-order 8 bits (0-7) in the I/O image table word, and the right-hand module is the high-order bits (10-17).