Siemens S7-200 PLC Addressing

Topic: CM479

Memory Type	Range	Description	Read/Write	Data Type	Memory Type
I	I	0.00 - 15.7	Input Memory	R/W	Bit
	IB	0 - 15			Byte
	IW	0 - 14			Word
	ID	0 - 12			Double Word
Q	Q	0.00 - 15.7	Output Memory	R/W	Bit
	QB	0 - 15			Byte
	QW	0 -14			Word
	QD	0 - 12			Double Word
M	M	0.00 - 31.7	Internal Memory	R/W	Bit
	MB	0 - 31			Byte
	MW	0 - 30			Word
	MD	0 - 28			Double Word
SM	SM	0.00 - 549.7	Special Internal Memory	Read Only	Bit
	SMB	0 - 549			Byte
	SMW	0 -548			Word
	SMD	0 - 546			Double Word
V	V	0.00 - 10239.7	Internal Variable memory	R/W	Bit
	VB	0 - 10239			Byte/String
	VW	0 - 10238			Word
	VD	0 - 10236			Double Word
T	T	0 - 255	Timer Done	Read Only	Bit
T	TW*	0 - 255	Timer Acc.	R/W	Word
C	C	0 - 255	Counter Done	Read Only	Bit
C	CW*	0 - 255	Counter Acc.	R/W	Word
AIW		0 - 62	Analog Input	Read Only	Word
AQW		0 - 62	Analog Output	R/W	Word
* These addresses are accessed without the W in the PLC by simply changing the Data type to a numeric form, e.g. the tag C-more shows as C1 will be C1, format “Bit” in the PLC and the tag C-more shows as CW1 will be C1, format “Signed” in the PLC.