adccommunitymod (AutomationDirect) asked a question.
Created Date: February 25,2018
Created By: spyder_walker
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I am trying to read a value to ea3 screen from PLC via Modbus. In PLC I have a REAL value between 0-50. On EA3, however the number is a 5 digit to 7 digit number. PLC is sending it as two addresses 40070, 40071, EA3 is setup as 0070 with a memory type of 4, unsigned Int 32. I have tried all the signed, unsigned, 16, 32 and can't seem to be getting a valid value being transferred from PLC to EA3. Number Is not even stable, jumps from 5132 to 90000 and back again. I am using the memory type 4 as these are holding registers. PLC address is set to 5 digit 40070, 40071. Thanks very much.
Created Date: February 25,2018
Created by: spyder_walker
I am trying to read a value to ea3 screen from PLC via Modbus. In PLC I have a REAL value between 0-50. On EA3, however the number is a 5 digit to 7 digit number.
PLC is sending it as two addresses 40070, 40071, EA3 is setup as 0070 with a memory type of 4, unsigned Int 32. I have tried all the signed, unsigned, 16, 32 and can't seem to be getting a valid value being transferred from PLC to EA3. Number Is not even stable, jumps from 5132 to 90000 and back again.
I am using the memory type 4 as these are holding registers. PLC address is set to 5 digit 40070, 40071.
Thanks very much.
Created Date: February 25,2018
Created by: kewakl
I am trying to read a value to ea3 screen from PLC via Modbus. In PLC I have a REAL value between 0-50. On EA3, however the number is a 5 digit to 7 digit number.
PLC is sending it as two addresses 40070, 40071, EA3 is setup as 0070 with a memory type of 4, unsigned Int 32 . I have tried all the signed, unsigned, 16, 32 and can't seem to be getting a valid value being transferred from PLC to EA3. Number Is not even stable, jumps from 5132 to 90000 and back again.
I am using the memory type 4 as these are holding registers. PLC address is set to 5 digit 40070, 40071.
Thanks very much.
In the EA3, try setting the Tag Data Type to Floating PT 32.
Created Date: February 25,2018
Created by: spyder_walker
Thankyou for quick response
That a little playing byte order, word order and character order in register helped.
Why Floating pt32 instead of signed integer 32?
I had to set byte order to high byte, low byte, word order to low word, high word, character order char2, char1.
Anyone want to explain this please...
Created Date: February 25,2018
Created by: OkiePC
"REAL " is a term that can be equated with the more specific term "32 bit float ". A 32 bit unsigned integer is a totally different representation of whole numbers.
More about integers (whole numbers) here:
https://en.wikipedia.org/wiki/Integer_(computer_science )
More about the most commonly used form of 32 bit real numbers here:
https://en.wikipedia.org/wiki/IEEE_754