Siemens S5-135U/155U System Manual page 437

Siemens network card system manual
Table of Contents

Advertisement

In the selective sampling mode, a measured value is encoded on the central
initiative of the CPU. At the start of conversion, the module must be
addressed once with a write operation (T PW) by the user program. An active
bit (T = 1) is set during encoding.
With the transition to T = 0, the measured value becomes valid. With
non-constant cycle times, there may be non-periodic measured value
aquisition. If you operate the module in this mode, you must set a module
address from 128 to 255. You can also use the address range from 0 to 127
for selective sampling after appropriate programming in DB 1 of the user
program.
Time-Controlled
Another method is that of time-controlled program processing. With this
Program
method, certain program segments (e.g. FB 13) are automatically inserted
Processing
into program processing at the 100 ms rate by a time-
controlled block (OB 13). A constant timebase is thus achieved.
FB 13
SEGMENT 1
NAME: SELSAMPL
0005
0006
0007
0008
0009
000A
000B
000C
000D
000E
000F
0010
Function Block
You can read analog values of analog input modules with a function block
from the "basic functions" package.
BASP (Output
The BASP signal is not interpreted by the 460 analog input module.
Inhibit)
System Manual
C79000-G8576-C199-06
SPRM-B
:
:
:L
PW128
:T
FW128
:S
F 129.2
:JC
= END
:T
FW10
:T
PB128
END
:
:
:BE
Analog Input/Output Modules
LEN=22
ABS
SHEET 1
EXAMPLE OF SELECTIVE SAMPLING
READ ANALOG VALUE
IN TO AUX: FLAG 128
SCAN ACTIVITY=1?
IF = 1, JUMP TO END
IF = 0, MEASURED VALUE IN FW 10
INITIATE SAMPLING
(1ST VALUE INVALID AFTER START)
9-55

Hide quick links:

Advertisement

Table of Contents
loading

This manual is also suitable for:

S5-135uS5-155u

Table of Contents