Internal Register Structures (continued)

Input registers WX49 ± WX54 consist of special flag bits that may be interrogated in the controller ladder program to detect alarm conditions, overrange or underrange conditions, or arithmetic overflow conditions due to scaling operations. See Figure 3-3.

WX49

Channel 1±16 Alarm flag bits

WX50

Channel 1±16 High alarm flag bits

WX51

Channel 1±16 Low alarm flag bits

WX52

Channel 1±16 Overrange flag bits

WX53

Channel 1±16 Underrange flag bits

WX54

Channel 1±16 Arithmetic overflow flag bits

WX55

Channel 1±16 Open Thermocouple flag bits

WX56

Channel 1±16 Front panel temperature

.WX64

Reserved for future use

For each word, the bits are correlated to the channels according to the following:

MSB

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LSB

 

1

 

0

0

0

0

0

0

0

0

0

0

0

0

0

0

 

16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CH 1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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CH 16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 3-3 Input Flag Bits

If the peak or valley hold functions are enabled and Y31=1, then the data returned in WX49 ± WX64 is the peak (Y30=1) or valley (Y30=0) value measured. See Table 3-3.

Table 3-3 Peak/Valley Hold Input Words

WX 49

.

.

WX 64

Channel 1

.

.

Channel 16

Peak/Valley value

.

.

Peak/Valley value

3-6

Advanced Function Programming

SIMATIC 505±2557 Installation and Operation Guide

Page 36
Image 36
Siemens 505-2557 installation and operation guide Input Flag Bits, Peak/Valley Hold Input Words