# OPC-UA device protocol - cyclic read vs. subscription

**URL:** <https://community.cumulocity.com/t/opc-ua-device-protocol-cyclic-read-vs-subscription/1443>\
**Category:** Forum\
**Tags:** device-connectivity, cumulocity\
**Created:** [May 10, 2022, 3:47pm UTC](https://community.cumulocity.com/t/opc-ua-device-protocol-cyclic-read-vs-subscription/1443 "2022-05-10T15:47:10Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![strasser.manfred](https://dub1.discourse-cdn.com/flex005/user_avatar/community.cumulocity.com/strasser.manfred/32/32198_2.png) [@strasser.manfred](https://community.cumulocity.com/u/strasser.manfred)\
**Post date:** [August 1, 2022, 6:41am UTC](https://community.cumulocity.com/t/opc-ua-device-protocol-cyclic-read-vs-subscription/1443/4 "2022-08-01T06:41:37Z")

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Hi there,  
I would like to add some information about this topic.

I am not sure if it is a good way to reply to this topic. Any suggestions are welcome.

**First** : a correction.  
As defined [here](https://reference.opcfoundation.org/v104/Core/docs/Part8/6.2/), the deadband in Percent is not a corresponding change of %-Value of the current value but rather depending on the EU-Range.

```auto
e.g. 
EU-Range High = 100.0
EU-Range Low = 50.0

Deadband Percent = 10% --> **deadband value = 5.0** // ( hi - low ) * deadband / 100.0

Calculation is done based on the last transmitted value

Examples:
The information in the original post suggests that it would need to change from 
50.0 to 55.0 
or
90.0 to 99.0 (10% of last transmitted value)

**Correct**
50.0 to 55.0
or
90.0 to 95.0

```

**Second** :  
There is a problem in the Current UI of the device-management (as of UI: 1011.0.12)  
In the section of the device-protocol where one could configure the deadband of the protocol, it does not work (there exists a workaround for e.g. Postman)  
It is supposed to be solved in  
UI: 1011.0.15 upwards

–  
BR Manfred

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