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4 Wiring with 800
4.4 Circuit diagram elements
110
Control Relay easy800 11/11 MN04902001Z-EN www.eaton.com
Retentive markers
You can declare a freely definable contiguous range between marker bytes
as retentive.
Device
easy800 standard
easy800-SWD
The setting of retentive markers is explained in ￫ section 8.2.6, "Retentive
data storage", page 308.
Number formats
The values of the marker byte (MB) and marker word (MW) data types are
processed as unsigned. In order to store negative values, you must use a
marker double word.
This fact must be particularly taken into account if the output of a function
block can take on a negative value. You must temporarily store this value in a
marker double word in order to transfer it to the input of a function block,
otherwise the sign information will be lost.
The easy800 device processes calculations with a signed 31-bit value.
The value range is: –2147483648 to +2147483647
With a 31-bit value, the 32nd bit is the sign bit.
Bit 32 = status 0 -> positive number.
Bit 32 = status 1 -> negative number.
Example:
00000000000000000000010000010010
Example:
11111110110111001111010001000111
Marker range that can be declared as retentive
MB01 - MB96
max. 400 bytes from MB01 - MB512
= 412
bin
= FEDCF447
bin
= 1042
hex
dec
= –19073977
hex
dez
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