Siemens SIMATIC NET Spezifikationen PDF herunterladen (Seite 196)

186 Siemens Simatic S7 Driver Online Help

Read

Algorithm

Reads from an S5 Time register.

Bits 11 to 0 of the Raw_value are

then separated into three nibbles (4

bits) prior to converting the value to

BCD. Each nibble is examined for a

value greater than 9 (A-F hex). If a

hexadecimal value between A and F

is found, a range alarm is generated,

indicating the value is not within

BCD range. Otherwise, the BCD

value is converted to seconds using

the following algorithm:

Result = (BCD_value *

Time_Resolution)

Read

Algorithm

Variables

Raw_value – the value stored in the

field device’s register.

Time_Resolution – the value stored

in bits 13 and 12 of the register

converted as follows:

00 – yields a resolution of 0.01

01 – yields a resolution of 0.1

10 – yields a resolution of 1

11 – yields a resolution of 10

BCD_Value – bit 11 to 0 of the

Raw_value converted into a

3BCD value.

Result – the scaled value stored in

the database block.

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Siemens SIMATIC NET Spezifikationen Seite 196