Description:
Operation of the controller via the operator panel can be released/locked not only via the user administration, but also using a key switch. This entry shows you one way to lock/activate access to specific screens using a key switch. This can be an external key switch that is connected to an ET200S, for example, or using a Mobile Panel with integrated key switch - see Fig. 01.

Contents:

1. How to lock operation with key switch
2. Programming in STEP 7
   2.1 Structure of the STEP 7 program
   2.2 Programming automatic screen selection
   2.3 Special feature of integrated key switch on Mobile Panel
   2.4 Data blocks used
3. Configuring in WinCC flexible
   3.1 Configuring with external key switch
   3.2 Configuring a Mobile Panel with integrated key switch
   3.3 Parameterizing WinCC flexible Runtime
4. Download

Fig. 01

Note:
As an alternative, you can also make the connection with the Industrial Ethernet.

Links:

• Information about locking multiple operator panels
  Entry ID: 32967536
• Information on user logon with chip card and card reader via RFID
  Entry ID: 26481978

1. How to lock operation with key switch
The operation lock in this example depends on the current position of the key switch and the screen that is open. If you call a released screen on the operator panel and then operate the key switch again, then the screen called is locked again. The locking can be realized by the deactivation of the separate objects in all the relevant screens or by the automatic screen selection for a screen that is not locked.
Object-related locking is implemented in the Start screen of the WinCC flexible project by deactivating the buttons.
This is also included in the sample project to demonstrate the automatic screen selection option. The screens to be locked are stored in a data block with a screen number. The screen numbers stored are compared with the current screen number. If the current screen number is stored in the data block and you operate the key switch again to lock operation, this starts the automatic screen selection.

2. Programming in STEP 7
Special features of the system must be taken into account when evaluating the position of the key switch integrated in the Mobile Panel. The external key switch is only simulated in this example. In a real system, you just have to replace the relevant parameter with the parameter of the (distributed) I/O (for example, E22.0).

2.1 Structure of the STEP 7 program
All the screens to be locked are stored in a matrix or data block. If operation is locked with the key switch, the basic screen is called automatically via the controller by a PLC job.

Large plants are usually divided into function groups. Similar to the entry dealing with "Locking multiple control panels" (see Entry ID: 32967536) the matrix is used as shown in Table 01.
 

Function group	Screen
	01	02	03	04	05	06	07	08	09	10
FG 00	1	-	-	-	-	-	-	-	-	-
FG 01	10	11	-	-	-	-	-	-	-	-
:	:	:	:	:	:	:	:	:	:	:
FG 10	-	-	-	-	-	-	-	-	-	-

Table 01

Figure 02 outlines the basic program for locking operation with the key switch.

Fig. 02

2.2 Programming automatic screen selection
Automatic screen selection can be used instead of object-related locking. The function or function module FC 502 must be called and parameterized appropriately for each operator panel.

Description of function FC 502
The function module FC502 "** ActivateScreen" does the automatic screen selection after release is locked via the key switch. Release via the key switch is transferred to the function module by the "Unlock" parameter. If the screen currently displayed on the operator panel is stored with the corresponding screen number in data block "DB500" and released is locked through the key switch, then the screen specified in the parameter "StartScreen" is selected automatically. The external parameterization is done primarily with data blocks DB501 "DB_AreaPointerScreenNo", DB502 "DB_AreaPointerJobMailbox" and DB505 "DB_Unlock".

Fig. 03
 

Parameter	Data type	Interface	Description
ActiveScreenNumber	Word	INPUT	Current screen number of operator panel
Unlock	Boolean	INPUT	Release via key switch
StartScreen	Word	INPUT	Target screen with automatic screen selection
ScreenDB	Any	INPUT	List of lockable screen numbers
Release	Boolean	OUTPUT	Release via key switch
AP_JobMailbox	Pointer	INOUT	Area pointer of controller job
StartsJob	Boolean	INOUT	Start of controller job
JobActive	Boolean	INOUT	Controller job is active
LoopCounter	Word	INOUT	Loop counter

Table 02 - Parameters of FC 502 "** ActivateScreen"

2.3 Special feature of integrated key switch on Mobile Panel
The system permits the Mobile Panel to be disconnected from the interface box. Undocking must be taken into account in the STEP 7 program to ensure that the key switch position is not inconsistent in the control program.

In addition to function module FC 502 for automatic screen selection you also need function module FC 503 in the Mobile Panel. Function module FC 503 evaluates the current key switch position.

Description of function FC 503
The function module FC 503 "** Keyswitch MobilePanel" cyclically updates the key switch position on the Mobile Panel. The toggling life bit of the operator panel is used for updating and is transferred in the "AuxiliaryTag" parameter. The operator panel's life bit transferred by the controller's "Coordination" area pointer and must be specified in the "Coordination" parameter. The "Keyswitch_PLC" parameter gives the operator panel's current key switch position.
 

Key switch position
Position		Process value
	Center	0
	Left	1
	Right	2

Table 03 - Key switch positions of the Mobile Panel "Keyswitch_PLC"

The operator panel's life bit is monitored by both timers. If the life bit does not change within two seconds, the key switch position is set to invalid and the "Unlock" parameter is reset. External parameterization is done primarily with data block DB505 "DB_Unlock".

Fig. 04
 

Parameter	Data type	Interface	Description
Timer_Low	Timer	INPUT	Timer for evaluation of the life bit by the operator panel (Low and High signal)
Timer_High	Timer	INPUT
WatchDogTime	S5Time	INPUT	Monitoring time of life bit
Valid	Boolean	OUTPUT	Key switch position is valid
Unlock	Boolean	OUTPUT	Release via integrated key switch
Coordination	Word	INOUT	"Coordination" area pointer of HMI
AuxiliaryTag	Int	INOUT	Update of the key switch position
Keyswitch_PLC	Int	INOUT	Key switch position

Table 04 - Parameters of FC 503 "** Keyswitch MobilePanel"

2.4 Data blocks used
The following data blocks are used in this sample project:
 

Data block
Number	Name	Description
DB8	DB_Coordination	DB for the HMI area pointer "Coordination"
DB500	DB_FunctionGroups	DB contains the matrix for the screen numbers to be locked
DB501	DB_AreaPointerScreenNo	DB for the HMI area pointer "Screen Number"
DB502	DB_AreaPointerJobMailbox	DB for the HMI area pointer "Controller job"
DB505	DB_Unlock	DB for operation locking and automatic screen selection

Table 05 - Data blocks used in STEP 7

3. Configuring in WinCC flexible
On a station operator panel, the external key switch is simulated by a button on the operator panel. When using the integrated key switch on the Mobile Panel, you must configure this explicitly on the operator panel.

3.1 Configuring with external key switch
The minimum configuration of WinCC flexible is described here.
 

No.	Procedure
1	Start WinCC flexible Open or start WinCC flexible ES. Mark the MP277, for example, and click on "OK". Fig. 05
2	Add screens Change the screen's name from "Screen_1" to "100_StartScreen" and change the screen number to "100". In the project tree, create two folders under "Screens" and name them "FG00" and "FG01". Add the screen "001_FG00_General" with screen number1" to the screen folder "FG00". In screen folder "FG01" you create the screens "010_FG01" and "011_FG01" with screen numbers "10" and "11" respectively. Fig. 06
3	Add libraries Download the WinCC flexible library "ConfigScreen.wlf", that is available at the end of this entry under Download. In the "Tools" window you right-click under the "Library" category to open the pop-up menu. In the pop-up menu you click on "Library... > Open". Then select the "ConfigScreen.wlf" library. Fig. 07
4	Add screens from library Use drag-and-drop to add the "Config" screen folder to the screens in the project tree. Fig. 08
5	Add buttons Add four buttons and arrange them as shown in Fig. 09. Label the buttons as follows: "FG00" "FG01" "Config" "Terminate RT" Fig. 09
6	Add system functions Link the following system functions to the buttons under the "Press" event:   No. Button System function 1 "FG00" Activate screen -Screen name: -Object name: "FG00\001_FG00_General" 0 2 "FG01" Activate screen -Screen name: -Object name: "FG01\010_FG01" 0 3 "Config" Activate screen -Screen name: -Object name: "Config\500_Param" 0 4 "Terminate RT" Stop Runtime -Mode: "Runtime" Fig. 10
7	Configure connection In the project tree, click on "Communication > Connections". Select the communication driver "SIMATIC S7 300/400". Configure the appropriate connection parameters. Fig. 11
8	Create area pointer Click on the "Area pointer" tab in "Connections". Create the area pointer "Screen number" and assign the corresponding address ("DB501.DBW0" in the first panel). Note: The tag address specified refers to the first panel. If you are using multiple panels, then the address must be changed accordingly - see DB501 in the STEP 7 project.   Activate the "Controller job" area pointer and assign the corresponding address ("DB502.DBW0" in the first panel). Note: The tag address specified refers to the first panel. If you are using multiple panels, then the address must be changed accordingly - see DB502 in the STEP 7 project. Fig. 12
9	Create tags Create the three following tags in the tag editor:   No. Tag Address 1 "DB_Unlock.Panel_01.Unlock_Release" DB505.DBX0.1 2 "DB_Unlock.Panel_01.Unlock_Key" DB505.DBX0.0 Note: The tag addresses specified refer to the first panel. If you are using multiple panels, then the address must be changed accordingly - see DB505 in the STEP 7 project. Fig. 13
10	Connect tags Activate the animations listed for the "FG00" and "FG01" buttons:   No. Button Animation 1 "FG00" Layout -Tag: -Value 0: -Value 1: "DB_Unlock.Panel_01.Unlock_Release" Foreground: gray Foreground: black Operability -Tag: -Status: -Area: "DB_Unlock.Panel_01.Unlock_Release" Activated from "1" to "1" 2 "FG01" Layout -Tag: -Value 0: -Value 1: "DB_Unlock.Panel_01.Unlock_Release" Foreground: gray Foreground: black Operability -Tag: -Status:  -Area:   "DB_Unlock.Panel_01.Unlock_Release" Activated from "1" to "1" Fig. 14
11	Add key switch In this example, the key switch is simulated as a visual switch by WinCC flexible. Open "Template". Add a "switch" to the "template". Change type from "Switch" to "Switch with text". Note: Alternatively you can also insert a "Switch with graphics" - as in the sample project.   Label the buttons as follows:   Value Label 0 Closed 1 Open   Link the "DB_Unlock.Panel_01.Unlock_Key" tag with the switch. Fig. 15

3.2 Configuring a Mobile Panel with integrated key switch
Below is a description of how to configure the key switch on the Mobile Panel.
Configuring is based on the description in section "3.1 Configuring with external key switch".
 

No.	Procedure
1	Open/create a Mobile Panel project Start WinCC flexible. Open or create a WinCC flexible project in a Mobile Panel - see also Figure 05.
2	Create tags Open the Tag Editor of the WinCC flexible project. Create the following tags:   No. Tag Connection Data type Address 1 Keyswitch_PLC External Int DB 505.DBW14 2 AuxiliaryTag External Int DB505.DBW12 3 Position_Keyswitch Internal Int - Note: In the case of integrated project, you can also use the symbolic connection. The symbolic connection matches the tag name to the symbolic name - see Fig. 16. Fig. 16
3	Configure system functions For the following tags, you configure the listed system functions for the "Value change" event - see also Fig. 16:   No. Tag System function 1 AuxiliaryTag SetValue -Tag: -Value: Keyswitch_PLC Position_Keyswitch 2 Position_Keyswitch SetValue -Tag: -Value: Keyswitch_PLC Position_Keyswitch Note: The "Position_Keyswitch" tag gives the current key switch position. In order to have the key switch position updated cyclically in the controller via the "Keyswitch_PLC" tag, you must add the "SetValue" system function to the "Value change" event of the "AuxiliaryTag" tag. Fig. 17
4	Connect tag to key switch Open the template. Click on the key switch and open the Properties window if required. Connect the "Position_Keyswitch" tag. Fig. 18

3.3 Parameterizing WinCC flexible Runtime
The corresponding screens must be stored in the data block for the automatic screen selection to be activated during Runtime.
 

No.	Procedure
1	Start WinCC flexible Runtime Transfer the project to the operator panel or start the WinCC flexible Runtime. Press on the "Config" button. Fig. 19
2	Parameterize operator panel Enter the number of function groups, the number of operator panels and the number of the operator panel. Then click the "Screens" button. Fig. 20
3	Parameterize function groups Enter screen number "1" in "FG00". Enter screen numbers "10" and "11" in "FG01". Then press "Back". Press the "Basic screen" button - see Fig. 20. Fig. 21
4	Unlock function groups Operate the key switch or press the key (1) for simulation of the key switch to release the screens. Press the "FG01" button (2). Fig. 22
5	Lock function groups Lock function groups again with the key switch or simulation switch. Note: If the screen number is entered in the data block and you have parameterized FC 502 accordingly, then the parameterized screen - the basic screen, for example - is selected by the automatic screen selection. Terminate the WinCC flexible Runtime. Fig. 23

4. Download
Attachment 1 contains the sample project described including the Mobile Panel 277 with integrated key switch and the stationary operator panel with simulation switch.

Attachment 1: WinCC_flexible_Keyswitch_Interlock.zip ( 4859 KB )

Attachment 2 contains the WinCC flexible library "ConfigScreen.wlf" with the two configuration screens.

Attachment 2: WinCC_flexible_Library_ConfigScreens.zip ( 983 KB )

Runnability and test environment:
The following table lists the components that have been used to create this entry and verify the functions described.
 

Components	Product and version designation
PC operating system	Microsoft Windows XP SP2
Standard tools	-
Engineering tool	STEP 7 V5.4 SP4
HMI software	WinCC flexible 2007 HF4
HMI system	MP 277 & Mobile Panel 277

Keywords:
Operation lock, Key, Lock