Hi all,

I am starting a project where I have to convert a PLC5 plc to Logix 5000. The code side is easy, I just have a question about the IO. Currently in the PLC 5 main rack, there is the CPU and then the rest of a 16 slot chassis is taken up with IO. There is then a RIO link to a remote rack with a 1771-ASB adaptor with a full rack. The RIO is then daisy chained to 5 further Remote Flex IO racks with 1794-ASB modules and then full racks of IO.

What I am attempting to do is provide a new CLX with a 1756-DHRIO card and then replace the PLC5 cpu with another 1771-ASB module and leave all the rest of the existing hardware.

Is there any fore seeable problems with doing this? Also if anybody has any examples of this type of configuration in Logix 5000 that they could post I would really appreciate it.

Thanks in advance

I believe it will depend on the contents of the existing racks. Also note that you will turn your local I/O in the current system into remote I/O and therefore affect the update speed and repeatability that the system presently has. The controllogix CPU will be much faster than the PLC5 at solving logic, but reading the first rack of I/O via the DHRIO/1771-ASB will probably not be as fast and repeatable as with the PLC-5 scanning it directly every cycle. This may or may not be a problem depending on the machinery being controlled.

I have no first hand experience with RIO via controllogix but have read a few comments about the limitations of such arrangements. I would suggest you make a complete list of the I/O modules and reply back here as well as thoroughly read up on the DHRIO module and its known limitations.

Paul

I have been in on at least 6 conversions to date. Most of them were multiple PLC5's to a single CLGX. We used the 1756-DHRIO back when ControlNet would not support 1771-XY cards.

My preference in a situation like this is to replace all the 1771-ASB's and the 1785-CPU with 1771-ACN's.

Using 1771-ASB's you'll need messages to read the inputs and outputs from the ASB's.

ControlNet is simpler for tags and programming, but you will need RSNETWORX.

Unfortunately my customer does not want to spend a lot of money so changing to Control Net is not an option. And as regards update times, this in not really an issue because it is not a critical process that is being controlled. I am putting an exact copy of the IO config into the logix down to all of the analog card configurations (I am just copying the INT values from the PLC5 data tables and putting them into the Logix)

It was just if there was anything out of the ordinary that I have to do in Logix that would not have been done in the PLC5 i.e Card initialization, IO mapping etc.

Thanks in advance

Here is a guide I made when doing a CLX from PLC5 reusing the PLC5 racks with the existing IO.

Configuration for DH+
Look at prints for how many racks
Look at io configuration for how many racks
configure 1756-DHRIO for correct configuration
Its not obvious how many racks are attached to the plc based on above
Ask these questions: Full, half, or 1/4 rack? Complementary io or not?
Full Rack Physically either 16 slots or 8 slots
16 slots complementary io
8 slots non complementary io
setup of 1756-DHRIO card
if using dh+ on channel a, if channel b is RIO then the baud rate can only be set to 57kbaud
if only using rio then use only channel a, then RIO baud rate can be set for 57 or 213kbaud rate
This is the dip sw changes for the processor plc5 that is changing to an asb card
DIP switch settings
note prior dip switch setting of processor and backplane settings
backplane dip sw of processor
1 2 3 4 5 6 7 8
on x
off x x x x x x x
On= 6, rest are off
backplane dip sw of 1771-ASB in first rack replacement
1 2 3 4 5 6 7 8
on x
off x x x x x x x
On= 2, rest are off

dip switch under first card
set to the "NO" Position
no change in this setting
Program conversion
Map old io with same wire numbers with the panel prefix
alias the wire numbers to the physical configuration location
All inputs need buffering in the IO inputs
Copy functionality of all old files into contrologix


Use the attachment on pdf notes out of the plc5 setting of dip switches.

Hello Again,

I am just having a few problems with setting up the configuration tree in Logix for my RIO Racks. So I was wondering if someone could help me.

In my existing IO there is the following:-
Chassis 1
PLC5 80E,
RACK 0 DC Input 10-30V 32 In, DC Input 10-30V 32 In, DC Input 10-30V 32 In, DC Input 10-30V 32 In
RACK 1 DC Output 10-60V 18 Out, DC Output 10-60V 18 Out, DC Output 10-60V 18 Out, DC Output
10-60V 18 Out
RACK 2 DC Output 10-60V 18 Out, DC Output 10-60V 18 Out, DC Output 10-60V 18 Out, DC Output
10-60V 18 Out
RACK 3 ANA IN 12 BIT, ANA IN 12 BIT, ANA IN 12 BIT, ANA OUT 12 BIT

Chassis 2
1771-ASB
RACK 4 ANA OUT 12 BIT, ANA OUT 12 BIT, ANA OUT 12 BIT, ANA OUT 12 BIT,
RACK 5 DC OUTPUT 10-60V 18 OUT, ANA OUT 12 BIT, DC OUTPUT 10-60V 18 OUT

RACK 10
1794 ASB, 1794 IB16, 1794 IB16, 1794 IB16, 1794 OB16, 1794 IB16, 1794 IE8

RACK 11
1794 ASB, 1794 IB16, 1794 IB16, 1794 IB16, 1794 IB16, 1794 IB16, 1794 IB16, 1794 IB16

RACK 12
1794 ASB, 1794 IB16, 1794 IB16, 1794 IB16, 1794 OB16, 1794 IE8, 1794 OE4

RACK 13
1794 ASB, 1794 IB16, 1794 IB16, 1794 IB16, 1794 IB16, 1794 IB16, 1794 OB16, 1794 IB16, 1794 IB16

RACK 14
1794 ASB, 1794 IB16, 1794 IB16, 1794 IB16, 1794 IB16, 1794 IB16, 1794 OB16, 1794 OB16

In My CHASSIS 1, I am removing the PLC5 CPU and replacing it with a 1771-asb
I have been searching on the web and found different opinions, some say that for the PLC 5 chassis's, I should have a 1771-asb configured for each rack, even though there is only 1 physical card. Also do I have to configure each card in each rack because in Logix, it only gives the option of a generic digital card or analog card.
So if someone could give me some pointers for this configuration I would really appreciate it.

Thanks in advance

Let Me See if I can Help Some. You must think in terms of Data Addresses Somewhat


Use a 1771ASB at Rack 0 Group 0 for a full rack 8 I/O groups. This will give you 8 Input Ints of 16 bits each that will correspond 1 to 1 with you 4 sets of 32 bits


Am a little confused by this one - Don't know of any PLC 5 18 output cards. Know of several 16 output cards with 18 terminals on the strip. I assumed you had a standard PLC 5 16 output card.

Use a 1771 ASB at Rack 1 Group 0 for full rack 8 I/O groups. This will give you 8 Input and 8 output Ints and will cover Racks 1 and 2


Use a 1771 ASB at Rack 3 Group 0 for a half rack 4 I/O Groups.
Then on this rack you'll need to add a Remote I/O Module for each analog Card.
Group 0 Slot 0 will be your first ANA IN
Group 1 Slot 0 will be your second ANA IN
Group 2 Slot 0 will be your third ANA IN
Group 3 Slot 0 will be your fourth ANA IN



Is Chassis 2 an 8 or 16 card slot rack. It will make a difference in how you configure for it.

For an 8 Card Rack with no Empty Slots.
Use a 1771ASB at Rack 4 Group 0 for a full rack 8 I/O groups.
Then on this rack you'll need to add a Remote I/O Module for each analog Card.
Group 0 Slot 0 will be your first ANA OUT
Group 1 Slot 0 will be your second ANA OUT
Group 2 Slot 0 will be your third ANA OUT
Group 3 Slot 0 will be your fourth ANA OUT

See Comment Above concerning 18 versus 16 pt modules.

The Outputs will be the last 4 16 bit ints of the data for this rack.

For an 16 Card Rack with 8 Empty Slots.
Use a 1771ASB at Rack 4 Group 0 for a half rack 4 I/O groups.
Then on this rack you'll need to add a Remote I/O Module for each analog Card.
Group 0 Slot 0 will be your first ANA OUT
Group 1 Slot 0 will be your second ANA OUT
Group 2 Slot 0 will be your third ANA OUT
Group 3 Slot 0 will be your fourth ANA OUT

See Comment Above concerning 18 versus 16 pt modules.

Use a 1771ASB at Rack 5 Group 0 for a half rack 4 I/O groups.

The Outputs will be the 16 bit ints of the data for this rack.



Use a 1794ASB at Rack 10 Group 0 for a three quarters rack 6 I/O groups.
The IB16 will line up with the Input Data Tag as will the OB16
Then on this rack you'll need to add a Remote I/O Module for each analog Card.
Group 5 Slot 0 will be your 1794-IE8


Use a 1794ASB at Rack 11 Group 0 for a full rack 8 I/O groups.


Use a 1794ASB at Rack 12 Group 0 for a three quarters rack 6 I/O groups.
The IB16 will line up with the Input Data Tag as will the OB16
Then on this rack you'll need to add a Remote I/O Module for each analog Card.
Group 4 Slot 0 will be your 1794-IE8
Group 5 Slot 0 will be your 1794-OE4



Use a 1794ASB at Rack 13 Group 0 for a full rack 8 I/O groups.


Use a 1794ASB at Rack 14 Group 0 for a full rack 8 I/O groups.


If this is not enough help post your attempt at laying out the tree and we'll try and guide you.

The attached Picture was my start at it until I hit the problem with racks 4 and 5.
[attachmentid=6999]

BobLfoot

Thank you very much for your help on the matter, Your explanation was extremely helpful. Racks 4 and 5 are in a 16 slot chassis, sorry for not making that more clear.....
About the DO cards, they are 16 out, sorry about that too....

Anyway, thanks again for your help....

No Problem Jay - Keep us psoted on how the conversion goes.

BTW a couple tricks from someone who has done several.
1. Keep the PLC 5/80 around and use weekend/down time for I/O check of your new. The conversion from 5 to 5000 can take less than an hour even on a large system. This lets you run your proven PLC 5 code until you've gained comfort with your conversion.

2. Create Tags with names like I000_00 ; I000_01 ; I000_02 and so forth and alias these to the actual Control logix names. This way your PLC 5 experienced folks will be able to find the ins and outs by much the same name as before. A real time saver when troubleshooting.

BobLfoot

I have configured the Logix as per your advice and have attached a screen shot of it below.
One thing that I have a question about is that For my Rack 3, you have said to assign the 3 Ana Ins and the 1 Ana Out to Groups 0,1,2,3 respectively. However, in the existing PLC5 code, the BTR's for these analogs are configured to look at groups 0,2,4,6 respectively. Is this just something that has changed in Logix or is there a different explantation. It is the same for all of the ana INs and OUTs. Also in the existing PLC5 Channel Properties it has Rack 4 and 5 as full racks whereas you have suggested 1/2 racks.
I am not questioning your advice because you obviously know more about it than I do, I was just wondering why there would be differences.

Also, thanks for your suggestions. I will create the alias tags because, as you say, it will make it an easier transition for the On Site service people

Again, thanks for your help.

Jay

Hi All

I thought that while I was on a roll of asking questions I might as well ask another one.

In my existing PLC5 code, double indirect addressing is used i.e. the data file and the word address
#N[N30:30]:[N30:10]

As far as I know, indirectly accessing the tag name cannot be done in CLX. So any advice on how to get around this, bearing in mind that the customer does not really want any more indirect code than I have to.

I have started trying converting the first tag value to a string and trying to build the required tag name that way but have not yet got it to work, so any help would be appreciated.

Thanks in advance

Jay

Jay if the original PLC 5 is using groups 0,2,4,6 then you'll probably need groups o,2,4,6 in your CLGX. This of course will mean changing rack 3 from a half to a full rack.

Concerning racks 4 and 5, I've been thinking about that also and I'd recommend on 2nd thought they be full racks. some of the data points will refer to empty slots but they need to be there.



Your code N[N30:30]:[N30:10] could refer to N17:10 if N30:30 is 17 and N30:10 is 10.

What you need in ControlLogix is a Tag I'd call mine Array_Integer_Data for example. It would need to be a DINT array of dimensions like 1000 for DIM1 and 255 for DIM 2.

You would also create tags Pointer1 and Pointer2. You could then have addresses like Array_Integer_Data([Pointer2],[Pointer1]). You would use Pointer2 for N30:30 and Pointer1 for N30:10.

I can't test the above since I am off for the weekend and without LOGIX 5000. But the theory is solid.

If you can't do double-indirect addressing, remember that a CLX can use expressions inside your indirect addressing function, unlike PLC-5. So you could create two_dim_table[2000], and then use an indirect address like this: two_dim_table[N30[30]*20+N30[10]]

If the client is too cheap to buy an ASB card, I'd consider just putting the PLC-5 into adapter mode and using it as your ASB card.

Second, one thing to watch out for when doing these conversions. Once you exceed 12 analog block transfers and especially when you get over 16 block transfers, there are some performance problems with a DHRIO card compared to the original native IO stuff. AB has some tech notes on this (and it's worth a phone call or two). My strong advice is to split your DHRIO runs into multiples if you can, trying mostly to balance out the block transfers and keep them under 8-10.

I ran into this myself on a recent conversion. We were converting 3 PLC-5's with their associated IO into a single CLX chassis. Once of the PLC's (31 nodes total) had to be split into two separate DHRIO channels because of performance problems.

You can avoid this problem a lot if you use timers to schedule your RIO. For instance, you can almost always reduce the block transfers to thermocouple cards down to say scanning once per second since the input data changes so slowly.

I see you configured the 1756-DRIO on channel B. This limits the baud rate to 57kbaud. Is this fast enough for your io? Reminder, if on channel B your baud rate can only be 57kbaud. So if you want to go to 230kbaud you might want to consider moving the IO to channel A.

Reminder, remember to buffer your IO since it can change during a program scan, that way your inputs will stay in the same state during program scan.

Startup idea, schedule a dry run a couple weeks before the the real turnover where you have the contrologix installed and can go through the procedure and checkout during this time. And if you have any snags you are not running around with your head cutoff and have time to respond with all the adjustments as necessary during the 2 weeks for the real turnover date.

Having been thru several PLC 5 to CLGX conversions let me suggest you take it a step further as follows:
This scheduled is based on the assumption that after production ends Friday you convert from PLC to CLGX wiring and that late on Sunday you convert back for a weeks production using PLC5.

1. Install your CLGX in a new panel with ability to run the RIO to the PLC5 Cabinet.

2. Plan on 2 or 3 weekends of non production time to verify your I/O and make sure all inputs and outputs are where you expected them to be.

3. Plan for 2 weekends of "Dry Shakedown" this lets you confirm timing and speeds of devices etc. No raw material is placed in the machine at this time.

4. Plan for 2 weekends of "Wet Shakedown" this lets you confirm production of each sub-component. Raw material in small quantities and batches is run. Usually the end of wet shakedown weekend #2 does not have a convert back to PLC 5 but marks the first production week on CLGX.

Hi all,

Thanks for all the advice about my installation. Unfortunately I dont have that kind of luxury. The plant runs 24/7. They have scheduled 5 days downtime for maintenance and it is during this down time that I have to do my changeover. So fingers crossed that all goes well. I am building a test rig in the office to test my comms as much as possible so hopefully all will go smoothly.

Jay