# Singel Vision Instance

**URL:** <https://forum.inductiveautomation.com/t/singel-vision-instance/29845>\
**Category:** General Discussion\
**Created:** [November 11, 2019, 3:00pm UTC](https://forum.inductiveautomation.com/t/singel-vision-instance/29845 "2019-11-11T15:00:36Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![roland.scheuer](https://avatars.discourse-cdn.com/v4/letter/r/c57346/32.png) [@roland.scheuer](https://forum.inductiveautomation.com/u/roland.scheuer)\
**Post date:** [November 11, 2019, 3:00pm UTC](https://forum.inductiveautomation.com/t/singel-vision-instance/29845/1 "2019-11-11T15:00:36Z")

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Hello,

is it possible to allow only 1 started Vision-Client Instance per computer.

Today i was looking on a Computer where operator started 8 Instances :S.

Many Thanks in advance.

br,  
Roland

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**Author:** ![JordanCClark](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jordancclark/32/83362_2.png) [@JordanCClark](https://forum.inductiveautomation.com/u/JordanCClark)\
**Post date:** [November 11, 2019, 3:49pm UTC](https://forum.inductiveautomation.com/t/singel-vision-instance/29845/2 "2019-11-11T15:49:46Z")

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Something like this in the client startup script:

```python
# Get current session info
tagNames =	['[System]Client/User/Username',
			 '[System]Client/System/ProjectName',
			 '[System]Client/Network/Hostname'
			]

tagsIn = system.tag.readBlocking(tagNames)

userName = tagsIn[0].value
project = tagsIn[1].value
hostName = tagsIn[2].value

# Get all session information
sessionInfo = system.util.getSessionInfo()

# Filter sessionInfo for matches of username, host and project.
x = [row for row in sessionInfo if row['username'] == userName and row['project'] == project and row['address'] == hostName]

# If there is more than one matching session, commit suicide
if len(x) > 1:
	from java.lang import System
	System.exit(0)

```

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<div class="post-metadata">

**Author:** ![roland.scheuer](https://avatars.discourse-cdn.com/v4/letter/r/c57346/32.png) [@roland.scheuer](https://forum.inductiveautomation.com/u/roland.scheuer)\
**Post date:** [November 11, 2019, 3:50pm UTC](https://forum.inductiveautomation.com/t/singel-vision-instance/29845/3 "2019-11-11T15:50:40Z")

</div>

perfect, this make sense 🙂  
Thank you

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<div class="post-metadata">

**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:** [November 11, 2019, 4:02pm UTC](https://forum.inductiveautomation.com/t/singel-vision-instance/29845/4 "2019-11-11T16:02:43Z")

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You might pop a message box and let them know what’s happening before they call support about the Vision client “crashing”… 😬

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<div class="post-metadata">

**Author:** ![JordanCClark](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jordancclark/32/83362_2.png) [@JordanCClark](https://forum.inductiveautomation.com/u/JordanCClark)\
**Post date:** [November 11, 2019, 4:11pm UTC](https://forum.inductiveautomation.com/t/singel-vision-instance/29845/5 "2019-11-11T16:11:43Z")

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Nope. No fun there. 😛

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**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:** [November 11, 2019, 5:14pm UTC](https://forum.inductiveautomation.com/t/singel-vision-instance/29845/6 "2019-11-11T17:14:37Z")

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Note that it won’t work properly for clients behind a NAT. If you need to support such clients, I recommend using the MacID in the client of the outbound network connection to uniquely identify the Vision client. Use system.util.sendRequest to report new clients to the gateway, and a maintain a global map of client IDs vs MacIDs there.