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Modbus Simatic Manager: want to read the first byte

7/2/2023 3:02 PM	Rate (0)
mazur866 Member Joined: 4/17/2021 Last visit: 5/1/2025 Posts: 3 Rating: (0)	Thank you for the quick reply . I'm just starting to play with the s7-300 so I may have questions. I already have communication with my slave. it is the ambient temperature indicator. I want to read the first byte. the temperature is 27.0 C. I'm getting strange results, please help. ------------------------------------------------------------------------------------------ Split from Modbus Sample Project Simatic Manager. Attachment modbus.png (436 Downloads)
	Last edited by: Jen_Moderator at: 07/03/2023 11:31:03 New subject after splitting
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7/2/2023 3:04 PM	Rate (0)
mazur866 Member Joined: 4/17/2021 Last visit: 5/1/2025 Posts: 3 Rating: (0)	modbuspoll read Attachment modbus1.png (406 Downloads)

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7/3/2023 12:58 AM	Rate (0)
Saravana kumar Platinum Member Joined: 2/6/2009 Last visit: 9/26/2025 Posts: 940 Rating: (119)	Hi, Based the image from Modbus poll the data type seems to Int/Word (16 bit) where as in VAT table is reading as floating point (32 bit). Read the Int/Word variables from DB4.DBW 0 onwards. Also check the manual of the slave device if there is any byte swapping if you still not able to read as 16 bit variable.
	_______________________________________________________________ Best Regards T.Saravana Kumar "All for the Best"
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