# How many Logix tags can I have in a 500ms scan class?

**URL:** <https://forum.inductiveautomation.com/t/how-many-logix-tags-can-i-have-in-a-500ms-scan-class/20445>\
**Category:** Ignition\
**Created:** [October 30, 2018, 3:15am UTC](https://forum.inductiveautomation.com/t/how-many-logix-tags-can-i-have-in-a-500ms-scan-class/20445 "2018-10-30T03:15:40Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![dtamada](https://avatars.discourse-cdn.com/v4/letter/d/f14d63/32.png) [@dtamada](https://forum.inductiveautomation.com/u/dtamada)\
**Post date:** [October 30, 2018, 3:15am UTC](https://forum.inductiveautomation.com/t/how-many-logix-tags-can-i-have-in-a-500ms-scan-class/20445/1 "2018-10-30T03:15:40Z")

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Ignition 7.9.9  
Rockwell Control Logix 74 processor  
Time slice is 20 %

How many maximum number of tags can i create in ignition with scan class of 500 ms?

I try to add 1500 tags but load factor for that particular device is around 700 %.

Max connections requests : 4  
CIP connection is : 1500

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<div class="post-metadata">

**Author:** ![dtamada](https://avatars.discourse-cdn.com/v4/letter/d/f14d63/32.png) [@dtamada](https://forum.inductiveautomation.com/u/dtamada)\
**Post date:** [October 30, 2018, 3:20am UTC](https://forum.inductiveautomation.com/t/how-many-logix-tags-can-i-have-in-a-500ms-scan-class/20445/2 "2018-10-30T03:20:41Z")

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Hi,

Is it possible to create a SCADA with approximate 20000 tags per device using ignition with Scan class 1s sec.

Rockwell PLC : 1756 L74  
Time Slice : 20%

Thanks,

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<div class="post-metadata">

**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:** [October 30, 2018, 11:39am UTC](https://forum.inductiveautomation.com/t/how-many-logix-tags-can-i-have-in-a-500ms-scan-class/20445/3 "2018-10-30T11:39:33Z")

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Individual tags or aliases? No. Lots of elements (INTs, DINTs, REALs, etc) packed into arrays or structures that can be read in bulk with no gaps? Probably. Or very close. Try creating four arrays of 5000 DINTs each in your processor, and subscribing them in Ignition by themselves. (Disable all your other tags.) See what you get.  
BTW, if a connection path in Rockwell products supports buffer sizes above the default, they’ll generally support a buffer of 4000. There’s no point using 1500. Consider also switching from a time slice-based comms allocation to fixed periodic pacing of your PLC’s tasks. Eliminating the continuous task in a PLC (or converting it to periodic) generally yields better comms processing without sacrificing necessary logic latency.