SLC 500 5/05 to Compactlogix Messaging-Struggling to understand concept

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Aug 2016
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Good Evening ,

I'm sorry. so many PLC concepts I still struggle with. I need to move some 8 digit numbers from a SLC 500 5/05 processor to a CompactLogix L33ER Processor. The following are the IP Addresses of each.

SLC 500 5/05 142.218.138.13
CompactLogix L33ER 142.218.138.91

I watched a few YouTube videos , I tried to duplicate those methods, but still struggling getting the concept down .

Have you folks seen any good technotes , manuals , videos , etc. that explain Messaging for a somewhat beginner ?

Thanks so much for your help in advance.
 
You will have an easier time creating the message in the Compactlogix. Doing it from the SLC is possible, but you will still need to use the PLC/SLC Mapping in the Compactlogix in order to get it to recognize the SLC type addresses that it will be receiving. That is the biggest hurdle, getting a file:word based address across as a tag with a name. The 2nd biggest hurdle can be the message path.
 
1. Describe exactly how your "8-digit numbers" are stored in the SLC.


2. When you have that data structure, replicate it exactly in the Logix 5000 (CompactLogix) processor.


3. Once you have those conditions, the MSG Read configuration becomes obvious.


More detail for more help.
 
Good Morning,

Thanks for the response. We have a SLC 5/05 processor that runs a large conveyor system. We are having an integrator install Cognex DataMan scanners on our palletizers . We have not updated our SKU product numbers for almost 10 years. We are just running our palletizer patterns close to a product that we ran in the past .

I'm in the process of updating our SKU numbers , but we do not message these numbers to any of the other machines associated with this process. The integrator is suppling the 1769-L33ER processor. I need to send the SKU product number to their L33ER from our SLC 500 5/05.

This number , such as 642233 is coming from Data File F100:100. So what I need to do is establish a Write Message in the SLC 500 5/05 IP Address 142.218.138.13 to the new CompactLogix L33ER IP Address 142.218.138.91.

How would you folks try to accomplish this ?

Thanks again . Sorry for the lack of information.
 
It would be much easier to READ F100:100 on the SLC from the CompactLogix than is to go the other way. To write to the Compact, you will need to setup PLC/SCL mapping that assigns a SLC-type data table to an tag named array. Either way, you will need to make modifications to the Compactlogix so its easier to just read the data. Also, if you do a READ, you can tell where the data is coming from, instead of it just magically appearing and more easily tell if the message is working.
 
Ok. I didn't think of it that way. I'm trying to find some samples from other programs in the plant , but I haven't found any that have the messaging that is similar . I will continue looking . Good advice .

Would you have a sample , link , or information that would help to simply read from the SLC 500 ?

I have both here in the office I will play with.

Thanks so much.
 
As Okie mentions, it really is preferable to do this in the CompactLogix.

Writing from the SLC to the Logix
The SLC is older than the Logix and doesn't understand the idea of tag names. To write from the SLC to the Logix controller, the Logix controller would have to make tags that look like traditional data files. This is called PLC/SLC Data Mapping. You would have to create the message in the SLC, then go into the Logix and create this mapping. So you must go into each system and make changes to get this to work.

CompactLogix reading data from the SLC
If you go to the Logix controller and create a MSG to READ from the SLC, things get much easier. The Logix knows about SLC data files so it can read from the SLC data files and store the data into Logix tags. Nothing has to be done in the SLC to make this work.

Consider This
Now the other thing to consider is that we generally prefer to READ instead of WRITE. If I am working in a controller that you are writing data to, I see data appearing, but I have no idea where it is coming from. This can be difficult to troubleshoot.

But, if I am reading the data from you, then in troubleshooting, I can trace back to my READ instruction which tells me what data I am getting and where it is coming from.

The only time I really would write data is if I need that data to update as fast as the network will allow. WRITE messages are faster than READ.

EDIT: Helliana was faster than me, but I figured I would post anyway

OG
 
As Okie mentions, it really is preferable to do this in the CompactLogix.

Writing from the SLC to the Logix
The SLC is older than the Logix and doesn't understand the idea of tag names. To write from the SLC to the Logix controller, the Logix controller would have to make tags that look like traditional data files. This is called PLC/SLC Data Mapping. You would have to create the message in the SLC, then go into the Logix and create this mapping. So you must go into each system and make changes to get this to work.

CompactLogix reading data from the SLC
If you go to the Logix controller and create a MSG to READ from the SLC, things get much easier. The Logix knows about SLC data files so it can read from the SLC data files and store the data into Logix tags. Nothing has to be done in the SLC to make this work.

Consider This
Now the other thing to consider is that we generally prefer to READ instead of WRITE. If I am working in a controller that you are writing data to, I see data appearing, but I have no idea where it is coming from. This can be difficult to troubleshoot.

But, if I am reading the data from you, then in troubleshooting, I can trace back to my READ instruction which tells me what data I am getting and where it is coming from.

The only time I really would write data is if I need that data to update as fast as the network will allow. WRITE messages are faster than READ.

EDIT: Helliana was faster than me, but I figured I would post anyway

OG


This is great info, would definitely be way easier to do the messaging from the CompactLogix side. Once you understand how to format the messages, such as addresses in target device, number of elements (in words) etc, the trickiest part is determining the message path. There are some good articles and forum posts out there, but I've been having a bit of a problem finding the one that really helped me understand the format. I think Ron Beaufort made a good post about it one time, if I can find it I'll post the link.


EDIT:


Found a good example from SMOKE in another thread:



his answer ID describes how to create the correct path for a MSG instruction from a ControlLogix processor to another ControlLogix processor using Ethernet with two Ethernet cards (example 1756-ENBT) The controller that initiates the message instruction has the following path (separated by commas, no spaces):
1,S1,2,xxx.yyy.zzz.www,1,S2
Where:

  • 1 is the backplane for the first chassis (the clx backplane always uses 1)
  • S1 is the slot of the 1756-ENBT in the first chassis (the first position on the left is 0, second 1,...)
  • 2 is to go outside to the Ethernet (always 2)
  • xxx.yyy.zzz.www is the IP address of the 1756-ENBT in the second chassis
  • 1 is the backplane for the second chassis (always 1 for clx)
  • S2 is the slot of the CLX in the second chassis (starting from left the first position is 0, second 1,...)
Example 1,3,2,192.168.1.4,1,0


Now these numbers depend on things like method of communication, so the 2 for Ethernet could be different if you're using ControlNet or DH+ for example. What I find really helpful is breaking the path down into three parts:


[A,B],[Q,R],[Y,Z]


has the following format:


[PLC1 backplane,PLC1 comms card location],[message comms protocol,PLC2 comms address],[PLC2 backplane,PLC2 processor slot]
 
Last edited:
From a CompactLogix to an SLC it is a little easier.......

2 = Out the Ethernet port on the CompactLogix
Then the IP Address for the SLC

Here is an example
2, 192.168.1.99

OG
 
From a CompactLogix to an SLC it is a little easier.......

2 = Out the Ethernet port on the CompactLogix
Then the IP Address for the SLC

Here is an example
2, 192.168.1.99

OG


Good to know, I've only ever dealt with either Logix to Logix/Micro on Ethernet or Logix to PLC-5 on DH+ so I wasn't sure how it would specifically go for a SLC over Ethernet. Thanks!
 
Thanks for all your reply's , and advice. Everything seems to working well on my Messaging.

I just have another question . I trying to look at the status of an internal bit in my SLC 500 . B3:0/1 on the CompactLogix side. It seems like Messaging does not like BOOL's . I keep getting after I select "Apply" …….
" Failed to save configuration for tag. Message references a tag of BOOL data type "

What is the best way to drill down and see the status of a bit in a SLC 500 thru a READ message in a CompactLogix . Thanks again.
 
The data structure of a B table in a SLC is an INT and different than the BOOL structure. Make an INT array in the compactlogix as the destination. You will have to move the entire words, then use the individual bits as needed. For example, you could make an array named B3, and then message B3:0 with 20 elements. B3:5/0 would then be B3[5].0 in the compactlogix.
 
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