Siemens S5-135U/155U appendix To AUX Flag

Analog Input/Output Modules

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		SPRM-B	LEN=22	ABS
					SHEET 1
	SEGMENT 1
	NAME: SELSAMPL			EXAMPLE OF SELECTIVE SAMPLING
	0005	:
	0006	:
	0007	:L	PW128	READ ANALOG VALUE
	0008	:T	FW128	IN TO AUX: FLAG 128
	0009	:S	F 129.2	SCAN ACTIVITY=1?
	000A	:JC	= END	IF = 1, JUMP TO END
	000B	:T	FW10	IF = 0, MEASURED VALUE IN FW 10
	000C	:T	PB128	INITIATE SAMPLING
	000D END	:		(1ST VALUE INVALID AFTER START)
	000E
	000F	:
	0010	:BE

Function Block You can read analog values of analog input modules with a function block from the ªbasic functionsº package.

BASP (Output	The BASP signal is not interpreted by the 460 analog input module.
Inhibit)

System Manual	9-55
C79000-G8576-C199-06