VM overview

As the interface for S7 communication, VM (Variable Memory) is used as a local communication buffer for data exchange by means of connection/data-transfer configuration.

The network topology can only be constructed through LOGO!Soft Comfort by Tools -> Ethernet Connections.

The data exchange process is described as follows:

• The Server stores the required data into the VM area specified by S7 connection and data transfer. This is defined as a "share" action in the following section.

• The Client unit reads the Server's VM area and then updates the corresponding local VM area in its network process step.

• After the local update, the circuit program in the Client can use the information in the local VM originated from the Server.

Data type and VM address

The following illustrates VM addressing and data type usage.

Create a parameter VM mapping

You can update inputs, outputs and markers to the local VM automatically. Also, you can change a parameter value in the local VM, and then the value in LOGO!Soft Comfort is changed accordingly. In this way, the information in LOGO!Soft Comfort and the information in the local VM are synchronized with each other in real time. Through the parameter VM mapping function, you can create a mapping between a block and a VM. The parameter values of a block are synchronized to the specified VM each cycle. After the synchronization, the VM can be used to communicate with other SIMATIC devices. You can have up to 64 parameters mapped in the VM for each LOGO! 0BA7 Base Module. A configuration dialog of parameter VM mapping is shown as follows:

The SFBs that have parameters in the current program are listed in the Block column. The Parameter column provides a select list of the parameters of the corresponding block. The Type column displays the data type of the selected parameter. The Address column is also configurable. It`s used to identify the VM address used to save a parameter value.

The flag behind a parameter name indicates the property of this parameter:

	The parameter value is a setting value and is writable.
	The parameter value is an actual value and is read-only.
	Although the parameter value is an actual value, the value still can be changed. NOTE: Only the Counter parameter of Up/Down counter has such a flag.
	The parameter value is referenced from an actual value of another already-programmed function block.
Note that if no flag appears, then the parameter value is a system value and cannot be changed.

Within the parameter VM mapping window, you can:

• select multiple record lines by pressing the Ctrl key or Shift key and clicking the ID of the desired line.

• insert a down line by pressing Enter key on the last cell of the desired line

• insert a up line by clicking the ID of the desired line and pressing the Insert key, or right-clicking the desired line and selecting Insert Row from the context menu.

• delete a line by clicking the ID of the desired line and pressing the Delete key, or right-clicking the desired line and selecting Delete from the context menu.

You cannot change the parameter type and must configure a unique address for each parameter. Range for a parameter address is from 0 to 850. If the value you input exceeds this range, inputs and outputs will be addressed to the specific VM addresses. The following table provides mappings between I/Os and VM addresses.

DI	VM Address	DQ	VM Address
I1	V923.0	Q1	V942.0
I2	V923.1	Q2	V942.1
I3	V923.2	Q3	V942.2
I4	V923.3	Q4	V942.3
I5	V923.4	Q5	V942.4
I6	V923.5	Q6	V942.5
I7	V923.6	Q7	V942.6
I8	V923.7	Q8	V942.7
I9	V924.0	Q9	V943.0
I10	V924.1	Q10	V943.1
I11	V924.2	Q11	V943.2
I12	V924.3	Q12	V943.3
I13	V924.4	Q13	V943.4
I14	V924.5	Q14	V943.5
I15	V924.6	Q15	V943.6
I16	V924.7	Q16	V943.7
I17	V925.0
I18	V925.1
I19	V925.2
I20	V925.3
I21	V925.4
I22	V925.5
I23	V925.6
I24	V925.7
AI	VM Address	AQ	VM Address
AI1	VW926	AQ1	VW944
AI2	VW928	AQ2	VW946
AI3	VW930
AI4	VW932
AI5	VW934
AI6	VW936
AI7	VW938
AI8	VW940
AM	VM Address	M	VM Address
AM1	VW952	M1	V948.0
AM2	VW954	M2	V948.1
AM3	VW956	M3	V948.2
AM4	VW958	M4	V948.3
AM5	VW960	M5	V948.4
AM6	VW962	M6	V948.5
AM7	VW964	M7	V948.6
AM8	VW966	M8	V948.7
AM9	VW968	M9	V949.0
AM10	VW970	M10	V949.1
AM11	VW972	M11	V949.2
AM12	VW974	M12	V949.3
AM13	VW976	M13	V949.4
AM14	VW978	M14	V949.5
AM15	VW980	M15	V949.6
AM16	VW982	M16	V949.7
		M17	V950.0
		M18	V950.1
		M19	V950.2
		M20	V950.3
		M21	V950.4
		M22	V950.5
		M23	V950.6
		M24	V950.7
		M25	V951.0
		M26	V951.1
		M27	V951.2

The LOGO! 0BA7 Base Module can share the following data by S7 communication interface:

Data Type	Number	Memory Type
Digital input	24	Byte
Digital output	16	Byte
Digital flag	27	Byte
Analog input	8	Word
Analog output	2	Word
Analog flag	16	Word
Value parameter	**	**
Actual value	**	**

The length (Byte, Word, or DWord) indicates the number of bytes in the VM area required by the parameter.

Block parameters that you specify in the Variable Memory Configuration dialog are linked to a VM address.

Not all of the VM area is available for configuration. Some bytes of the VM area are reserved. You cannot specify more than 64 parameters. If you attempt to specify more than 64, LOGO!Soft Comfort displays a failed operation message.

Parameter settings

Function Block	Data type	Read/Write	Parameter settings in LOGO!Soft Comfort	Parameter settings on a partner device
On-Delay
Current Time	VW	R
On-Delay	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Remaining Time	VW	R
On-Delay Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Off-Delay
Current Time	VW	R
On-Delay	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Remaining Time	VW	R
On-Delay Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
On-/Off-Delay
Current Time	VW	R
On Time (TH)	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Off Time (TL)	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
On Time (TH) Remaining Time	VW	R
Off Time (TL) Remaining Time	VW	R
On Time (TH) Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Off Time (TL) Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Current Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Retentive On-Delay
Current Time	VW	R
On-Delay	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Remaining Time	VW	R
On-Delay Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Wiping Relay (Pulse Output)
Current Time	VW	R
Off Time (TL)	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Off Time (TL) Remaining Time	VW	R
Off Time (TL) time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Edge Triggered Wiping Relay
Current Time	VW	R
Pulse Width (TH)	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Interpulse Width (TL)	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Pulse Width (TH) Remaining Time	VW	R
Interpulse Width (TL) Remaining Time	VW	R
Pulse Width (TH) Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Interpulse Width (TL) Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Current Time Base	VB	R	10 milliseconds	1
			Seconds	2
			Minutes	3
Asynchronous Pulse Generator
Current Time	VW	R
Pulse Width	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Interpulse Width	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Pulse Remaining Time	VW	R
Interpulse Remaining Time	VW	R
Pulse Width (TH) Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Interpulse Width (TL) Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Current Time Base	VB	R	10 milliseconds	1
			Seconds	2
			Minutes	3
Random Generator
Current Time	VW	R
Max. On Delay (TH)	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Max. Off Delay (TL)	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Max. On Delay (TH) Remaining Time	VW	R
Max. Off Delay (TL) Remaining Time	VW	R
Max. On Delay (TH) Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Max. Off Delay (TL) Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Current Time Base	VB	R	10 milliseconds	1
			Seconds	2
			Minutes	3
Stairway Lighting Switch
Current Time	VW	R
Off Delay	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Pre-Warning Time (T!)	VW	R
Pre-Warning Period (T!L)	VW	R
Off Delay Remaining	VW	R
Pre-Warning Time (T!) Remaining	VW	R
Pre-Warning Period (T!L) Remaining	VW	R
Off Delay Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Multiple Function Switch
Current Time	VW	R
Off Delay Time (T)	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Permanent Light (TL)	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Pre-Warning Time (T!)	VW	R
Pre-Warning Period (T!L)	VW	R
Off Delay Time (T) Remaining	VW	R
Permanent Light (TL) Remaining	VW	R
Pre-Warning Time (T!) Remaining	VW	R
Pre-Warning Period (T!L) Remaining	VW	R
Off Delay Time (T) Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Permanent Light (TL) Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Current Time Base	VB	R	10 milliseconds	1
			Seconds	2
			Minutes	3
Weekly Timer (When an entry box is set unavailable or a function is disabled, "0xFF" is displayed on an HMI or S7 PLC and "-" is displayed on a Base Module.)
Week Day 1	VB	R/W	Sunday	Bit 0
			Monday	Bit 1
			Tuesday	Bit 2
			Wednesday	Bit 3
			Thursday	Bit 4
			Friday	Bit 5
			Saturday	Bit 6
				NOTE: If the related bit is 1, then the day is set.
On Time 1	VW	R/W	h:m	h:m
Off Time 1	VW	R/W	h:m	h:m
Week Day 2	VB	R/W	Sunday	Bit 0
			Monday	Bit 1
			Tuesday	Bit 2
			Wednesday	Bit 3
			Thursday	Bit 4
			Friday	Bit 5
			Saturday	Bit 6
				NOTE: If the related bit is 1, then the day is set.
On Time 2	VW	R/W	h:m	h:m
Off Time 2	VW	R/W	h:m	h:m
Week Day 3	VB	R/W	Sunday	Bit 0
			Monday	Bit 1
			Tuesday	Bit 2
			Wednesday	Bit 3
			Thursday	Bit 4
			Friday	Bit 5
			Saturday	Bit 6
				NOTE: If the related bit is 1, then the day is set.
On Time 3	VW	R/W	h:m	h:m
Off Time 3	VW	R/W	h:m	h:m
Pulsely	VB	R/W	Off	0
			On	1
Yearly Timer (When an entry box is set unavailable, "0xFF" is displayed on an HMI or S7 PLC and "-" is displayed on a Base Module.)
On Time	VW	R/W	Month:Day	Month:Day
Off Time	VW	R/W	Month:Day	Month:Day
On Year	VB	R/W	Year	Year
Off Year	VB	R/W	Year	Year
Monthly	VB	R/W	No	0
			Yes	1
Yearly	VB	R/W	No	0
			Yes	1
Pulsely	VB	R/W	Off	0
			On	1
Astronomical Clock
Longitude	VD	R/W		VBx+0
			W	1
			E	0
			°	VBx+1
			'	VBx+2
			"	VBx+3
Latitude	VD	R/W		VBx+0
			S	1
			N	0
			°	VBx+1
			'	VBx+2
			"	VBx+3
Time Zero (E+; W-)	VW	R/W		-11 to 12 Low byte bit 7 means sign, for example: 00000001 10000000 means -1.
SunRise Time	VW	R		h:m
SunSet Time	VW	R		h:m
Stop Watch
Time Base	VB	R/W	10 milliseconds	0
			Seconds	1
			Minutes	2
			Hours	3
Current Time	VD	R
Lap Time	VD	R
Output Time	VW	R
Up/Down Counter
Counter	VD	R/W		0 to 999999
On Threshold	VD	R/W		0 to 999999
Off Threshold	VD	R/W		0 to 999999
start value	VD	R/W		0 to 999999
Hours Counter
Maintenance Interval (MI)	VD	R/W		0 to 599999 (9999H 59M)
Time-to-Go (MN)	VD	R
Total Time (OT)	VD	R
Threshold Trigger
Frequency	VW	R
On Threshold	VW	R/W		0 to 9999
Off Threshold	VW	R/W		0 to 9999
Gate Time	VW	R
Analog Threshold Trigger
On	VW	R/W		-20000 to 20000
Off	VW	R/W		-20000 to 20000
Gain	VW	R
Offset	VW	R
Ax, Amplified	VW	R
Analog Differential Trigger
On	VW	R/W		-20000 to 20000
Differential	VW	R/W		-20000 to 20000
Gain	VW	R
Offset	VW	R
Ax, Amplified	VW	R
Off	VW	R
Analog Comparator
On	VW	R/W		-20000 to 20000
Off	VW	R/W		-20000 to 20000
Gain	VW	R
Offset	VW	R
Ax, Amplified	VW	R
Ay, Amplified	VW	R
Ax (Amplified)-Ay (Amplified)	VW	R
Analog Watchdog
Gain	VW	R
Offset	VW	R
Aen (Comparison Value)	VW	R
Ax, Amplified	VW	R
Differential (+)	VW	R/W		0 to 20000
Differential (-)	VW	R/W		0 to 20000
Analog Amplifier
Analog Amplifier: Gain	VW	R/W		-1000 to 1000
Analog Amplifier: Offset	VW	R/W		-10000 to 10000
Analog Amplifier: Ax, Amplified	VW	R
Analog Multiplexer
AQ Amplified	VW	R
V1 (S1=0; S2=0)	VW	R/W		-32768 to 32767
V2 (S1=0; S2=1)	VW	R/W		-32768 to 32767
V3 (S1=1; S2=0)	VW	R/W		-32768 to 32767
V4 (S1=1; S2=1)	VW	R/W		-32768 to 32767
PWM
Min.	VW	R/W		-10000 to 20000
Max.	VW	R/W		-10000 to 20000
Gain	VW	R/W		-1000 to 1000
Offset	VW	R/W		-10000 to 10000
Ax, Amplified (Current Period)	VW	R
T	VW	R/W	Unit: Seconds	Value range: 0 to 9999
			Unit: Minutes or Hours	Value range: 0 to 5999
Periodic Time Time Base	VB	R/W	10 milliseconds	1
			Seconds	2
			Minutes	3
Mathematic Instructions
AQ Amplified	VW	R
V1	VW	R/W		-32768 to 32767
V2	VW	R/W		-32768 to 32767
V3	VW	R/W		-32768 to 32767
V4	VW	R/W		-32768 to 32767
Operator 1	VB	R/W		VBx+0
			+	0
			-	1
			*	2
			/	3
Operator 2	VB	R/W		VBx+0
			+	0
			+	1
			*	2
			/	3
Operator 3	VB	R/W		VBx+0
			+	0
			-	1
			*	2
			/	3
Priority1	VB	R/W	L	0
			M	1
			H	2
Priority2	VB	R/W	L	0
			M	1
			H	2
Priority3	VB	R/W	L	0
			M	1
			H	2
Reset Mode	VB	R/W	Reset to zero	0
			Keep last value	1
Analog Ramp
Gain	VW	R
Offset	VW	R
Current Level	VW	R
Level 1 (L1)	VW	R/W		-10000 to 20000
Level 2 (L2)	VW	R/W		-10000 to 20000
Largest Output Value	VW	R
Start/Stop Offset	VW	R/W		0 to 20000
Speed of Change	VW	R/W		1 to 10000
PI Controller
Set Value (SP)	VW	R/W		-10000 to 20000
PV, Amplified	VW	R
Aq	VW	R
Kc	VW	R/W		0 to 9999
Integeration Time (TI)	VW	R/W	Unit: Minutes	0 to 5999
Direction	VB	R/W	+	0
			-	1
Manual Output (Mq)	VW	R/W		0 to 1000
min	VW	R/W		-10000 to 20000
max	VW	R/W		-10000 to 20000
Gain	VW	R		-1000 to 1000
Offset	VW	R		-10000 to 10000
Analog Filter
Dialog Parameter Averge Value Sample Number	VB	R/W		3 to 8
			8	3
			16	4
			32	5
			64	6
			128	7
			256	8
Ax	VW	R
Aq	VW	R
Max/Min
Mode	VB	R/W		0, 1, 2 and other value
Ax	VW	R
Minimum Value	VW	R
Maximum Value	VW	R
Aq	VW	R
When reset=0, reset Min/Max	VB	R/W		0 or 1
Average Value
Sample Time	VW	R/W	Unit: Seconds or Minutes	Value range: 0 to 59
			Unit: Hours	Value range: 0 to 23
			Unit: Days	Value range: 0 to 365
Number of Samples	VW	R/W	Unit: Seconds	Value range: 1 to St*100
			Unit: Days	Value range: 1 to 32767
			Unit: Hours	Value range: 1 to 32767
			Unit: Seconds and ≤ 5 Minutes	Value range: 1 to St*6000
			Unit: Seconds and ≥ 6 Minutes	Value range: 1 to 32767
Ax	VW	R
Aq	VW	R
Sample Time Time Base	VB	R/W	Seconds	1
			Minutes	2
			Hours	3
			Days	4