# CIP Connection Size Parameter **URL:** \ **Category:** Ignition\ **Tags:** ignition79\ **Created:** [July 3, 2017, 11:42pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681 "2017-07-03T23:42:05Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [May 3, 2019, 3:40pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/21 "2019-05-03T15:40:03Z")
v20.55 works with the old driver? That’s interesting… what model even has a firmware 20.55 available? ---
**Author:** ![mreynolds](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/mreynolds/32/7515_2.png) [@mreynolds](https://forum.inductiveautomation.com/u/mreynolds)\ **Post date:** [May 3, 2019, 3:41pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/22 "2019-05-03T15:41:23Z")
1756-L75 ControlLogix 5575 Controller Revision 20.55 ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [May 3, 2019, 3:43pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/23 "2019-05-03T15:43:06Z")
Maybe the firmware ranges I mentioned only apply to CompactLogix then. Not sure what the story is for your model. ---
**Author:** ![mreynolds](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/mreynolds/32/7515_2.png) [@mreynolds](https://forum.inductiveautomation.com/u/mreynolds)\ **Post date:** [May 3, 2019, 3:45pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/24 "2019-05-03T15:45:17Z")
Maybe. It’s also worth noting that this driver was “just there” when Ignition was upgraded from 7.7.2 to 7.9.9 and I haven’t tried adding the controller again using the old driver. It also doesn’t work _well_ with the old driver which is why I was trying to test the newer one in the first place. ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [May 3, 2019, 3:49pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/25 "2019-05-03T15:49:14Z")
It seems like the Redundant variants are the ones with these .5x firmware releases… explains why I haven’t seen it at least. ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [May 3, 2019, 3:51pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/26 "2019-05-03T15:51:12Z")
There’s an interesting note [here](https://digitalsupport.ge.com/en_US/Article/Receiving-CIP-0x0F-Permission-Denied-in-the-IGS-Event-Viewer-log-Using-Firmware-V20-19) that suggests 20.55 happens to work but later versions would not. ---
**Author:** ![mreynolds](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/mreynolds/32/7515_2.png) [@mreynolds](https://forum.inductiveautomation.com/u/mreynolds)\ **Post date:** [May 3, 2019, 4:03pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/27 "2019-05-03T16:03:18Z")
I think at this point (since I’m already nearly done changing OPC addresses in all of the tags) it’s best to at least finish and try the performance with the new driver. If it doesn’t help I can always import my backup of the old tag structure and switch back. Like I mentioned before, with an increased CIP size I was seeing promising early results with this. ---
**Author:** ![richardNZ15](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/richardnz15/32/33373_2.png) [@richardNZ15](https://forum.inductiveautomation.com/u/richardNZ15)\ **Post date:** [July 11, 2021, 8:52pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/28 "2021-07-11T20:52:25Z")
Just going to provide an update on this one… I’m using a 1756-L85E v31.11. We were pushing our PLC MSG utilization to 85-100% (put PLC IP addr into web browser, see “Tasks” tab) with ~22k tags (reported by the Ignition Gateway/Status/Devices page). Scan class for majority of tags was set to Direct @ 1100ms. Ignition device connections are all set to 4 concurrent requests, 4000 CIP connection size. We have 4 device connections to the same PLC, but majority of load comes from 2 connections with aprox ~11k tags each. I’ve heard of these PLC’s being able to service up to 30k tags no problem. Does anyone have any tips on what they are doing to achieve this? I’m going to spend some time today trying to play with different scan classes and Device settings. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [July 11, 2021, 9:01pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/29 "2021-07-11T21:01:35Z")
Have you seen this discussion about AOI issues? > [@Cannot read some tags inside Rockwell AOI](http://forum.inductiveautomation.com/t/cannot-read-some-tags-inside-rockwell-aoi/38393/3): > > What Mike said, but also: Don’t. All AOI’s have EnableIn and EnableOut booleans that are locked to “Hidden” and therefore prevent most optimization of the data traffic to read instances of these data types. Ignition’s Logix driver cannot do bulk reads on AOIs. Do very much of this and your Logix driver will choke. I strongly recommend that any AOI you design yourself use one or more InOut parameters of another data type, with instances of those datatypes elsewhere. Place all of your extern… ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [July 11, 2021, 9:34pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/30 "2021-07-11T21:34:53Z")
Probably ought to review the discussions that also link to that post. ---
**Author:** ![richardNZ15](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/richardnz15/32/33373_2.png) [@richardNZ15](https://forum.inductiveautomation.com/u/richardNZ15)\ **Post date:** [July 11, 2021, 9:36pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/31 "2021-07-11T21:36:42Z")
Hi Phil, thanks no i hadn’t, but i’ve read quite a lot on the topic now, from that post and a few other related ones. One thing i did notice straight away, is that the EnableIn and Out booleans in the AOI’s are currently set to ReadOnly External Access in my project. You mentioned that they were forced to Hidden in older posts, is this something that is changed potentially? ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [July 11, 2021, 9:38pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/32 "2021-07-11T21:38:47Z")
Could be. I’ll play with Studio 5000 to see where that became possible. Or maybe it’s only possible for AOIs you create yourself. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [July 11, 2021, 11:04pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/33 "2021-07-11T23:04:09Z")
Hmmm. Everything back to v16 where AOIs were introduced show those booleans as External\_ReadOnly. The part that seems locked to hidden is the AOI’s Local tags. You can toggle display of the external access column for those, which then shows “ReadWrite”, but they aren’t. I need to confirm this in my lab tomorrow. I may have misidentified the culprit. ---
**Author:** ![richardNZ15](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/richardnz15/32/33373_2.png) [@richardNZ15](https://forum.inductiveautomation.com/u/richardNZ15)\ **Post date:** [July 11, 2021, 11:42pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/34 "2021-07-11T23:42:58Z")
Hi Phil, thanks for looking into it. We are using an AOI local tag that we can read from Ignition, and we have been doing so for quite a while. Interested to hear what you find out. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [July 12, 2021, 3:40pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/35 "2021-07-12T15:40:00Z")
Well, that was interesting. It isn’t an issue with external access. Or rather, setting every member of the AOI to read or read/write is _ **necessary** _ for bulk reads, but the Logix driver won’t do bulk reads on AOIs anyways. ): I’ve passed my findings on to @Kevin.Herron for future driver improvements. ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [July 12, 2021, 3:56pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/36 "2021-07-12T15:56:31Z")
Yes, to clear things up, our driver will not attempt to read Module-defined, Predefined, or AOI structures as a whole, at the recommendation of the Logix 5000 Controllers Data Access guide (1756-pm020). > IMPORTANT > The information described in this manual about accessing and understanding structures should not be used to access complete Module-Defined structures, Predefined structures, Add-On-Defined structures, or system tags, whether they are stand alone, an alias, or nested within another user created tag. Tags of these types have rules for dealing with host members and mapping of BOOLS, which are beyond the scope of this document. If such structures are manipulated or accessed, results can be unpredictable. Phil has shared some of his findings about how BOOLs are mapped in AOIs and PDTs and in the future I'll probably look into this to see if there are any other risks or rule changes involved in trying to read AOIs or PDTs, but I can't really put any timeline on it. ---
**Author:** ![richardNZ15](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/richardnz15/32/33373_2.png) [@richardNZ15](https://forum.inductiveautomation.com/u/richardNZ15)\ **Post date:** [July 12, 2021, 10:28pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/37 "2021-07-12T22:28:57Z")
Thanks guys for the updates. In terms of my own update, we’ve managed to get some stability from the PLC with the following changes: - set our Direct scan classes to 2500ms. - move a few UDT members from default fast Direct scan class to a slower direct scan class that didn’t need to be polled as often. Note 1: Adding additional device connections didn’t seem to help much (we already have multiple). Note 2: Increasing CIP connection size \> 4000 broke the connection. **Current stats:** Device Connection 1: 11k tags. Direct @ 2500ms. Request count 87, Mean response 17ms, Load Factor 15%. Device Connection 2: 11k tags. Direct @ 2500ms. Request count 180, Mean response 5ms, Load Factor 9%. EDIT: Don’t use any leased scan classes in this particular example. ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [July 12, 2021, 10:45pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/38 "2021-07-12T22:45:20Z")
Do you really see much difference between 2 devices with 4 logical CIP connections each vs 1 device with 8 connections? Usually we only recommend separate device connections where you put all your leased stuff on one and direct on the other so the relatively frequent re-optimization of the leased tags doesn’t affect the direct tags. ---
**Author:** ![richardNZ15](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/richardnz15/32/33373_2.png) [@richardNZ15](https://forum.inductiveautomation.com/u/richardNZ15)\ **Post date:** [July 12, 2021, 11:05pm UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/39 "2021-07-12T23:05:17Z")
I noticed a big difference when using the Omron driver for an NJ job, splitting 1 device connection into two. Can’t recall how many CIP connections were on the device connections at the time. I remember Cody saying they had better success with everything on Direct, but i think the part where we split Direct and Leased into different device connections may have been lost in translation somewhere. I’ll try have another go with that in mind. ---
**Author:** ![richardNZ15](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/richardnz15/32/33373_2.png) [@richardNZ15](https://forum.inductiveautomation.com/u/richardNZ15)\ **Post date:** [July 13, 2021, 4:33am UTC](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681/40 "2021-07-13T04:33:01Z")
To clarify, we don't actually have ANY leased scan classes in this particular project. I've updated my comment above to read: > - move a few UDT members from default fast Direct scan class to a slower direct scan class that didn’t need to be polled as often. Instead of: > - move a few UDT members from Direct to Leased scan classes that didn’t need to be polled regularly. [Previous page](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681.md?page=1) [Next page](https://forum.inductiveautomation.com/t/cip-connection-size-parameter/14681.md?page=3)