Eaton easy800, Руководство пользователя

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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.
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
bin
= 412
hex
= 1042
dec
Example:
11111110110111001111010001000111
bin
= FEDCF447
hex
= –19073977
dez
Device Marker range that can be declared as retentive
easy800 standard
MB01 - MB96
easy800-SWD
max. 400 bytes from MB01 - MB512