The following screen objects are available for the input and display of process values (Fig. 16.9):
b I/O field: Input and display of numerical values
b Symbolic I/O field: Input and display of numerical values with text support b Graphic I/O field: Input and display of numerical values with graphic support b Date/time field: Display of date and time
b Bar: Display of a numerical process value in the form of a bar graph
b Trend view: Display of several associated, numerical process values as a trend
The input and display of process values in association with alarms and recipes as well as user administration are described in the following sections. How to configure the objects can be found in Sections 16.3.8 “Working with objects in process screens”
on page 522 and 16.3.9 “Changing screen objects during runtime” on page 524.
HMI objects
The I/O field object is used for the input and display of process values. During con- figuration, you can define the mode in which the I/O field is to work during runtime:
Input, Input/output or Output. You can set that the input remains hidden (only aster- isks are then displayed) and you can assign an input privilege to the I/O field. Pos- sible display formats include the decimal value with sign and decimal place, date/time, and string. You can set a change in color depending on upper and lower limits.
Fig. 16.9 Screen objects for input and display of process values I/O field Symbolic I/O field
Switch Button
Date/time field
Bar Screen objects for input and display of process values
Graphic I/O field Trend view
The Symbolic I/O field object is used for the input or output of a process value with display of a text. If the I/O field is configured as an input field, a value is assigned to the configured tag depending on the displayed text which is selected from a text list during runtime. With an output field, the text stored in a text list is displayed, de- pending on the value of a selection tag. Working with text lists is described in the next section.
The Graphic I/O field object is used for the input or output of a process value with display of a graphic. If the I/O field is configured as an input field, a value is assigned to the configured tag depending on the displayed graphic which is selected from a graphics list during runtime. With an output field, the graphic stored in a graphics list is displayed depending on the value of a selection tag. Working with graphics lists is described in the next section.
The Date/time field object can be used to display and enter the date and/or time.
The date/time tag can be the system time of the HMI station or an HMI tag.
The Button object is used to trigger a configurable action. A function list with sys- tem functions can be processed depending on the event (e.g. press, release). The in- scription can be text or a graphic, either fixed or selected from a text or graphics list.
The processing of text, graphics and function lists is described in the next sections.
The Switch object enables the selection of two configurable states. The current state can be shown in the switch by a text or graphic. A function list with system functions can be processed depending on events (e.g. switch ON, switch OFF).
The processing of function lists is described in the section after next.
The Bar object displays a process value in graphic form. The display properties which can be set include: the color response (change in color on violation of limits), the marking of limits, the division into bar segments, and the scale inscriptions and division.
The Trend view object displays tag values in the form of trends. You can set trend display features with regard to position, geometry, style, color and font in the in- spector window. You can also specifically define whether a value table, a ruler or a grid is to be displayed in addition to the coordinate system.
Working with text and graphics lists
Text lists consist of individual texts which are assigned to the values of a tag. For ex- ample, a text list can be assigned as a selection list to a symbolic I/O field: if the I/O field is an input field, the tag assumes a specific value when a text is selected;
if the I/O field is an output field, the corresponding text is displayed if the tag has a specific value.
Graphics lists consist of individual graphics which are assigned to the values of a tag. A graphic can be present in a graphics library or be an existing file in the stan- dard file format. Graphics lists are handled like text lists.
A multilingual configuration is possible for a text or graphics list, which is dis- played in the current operating during operation (runtime). This is meaningful e.g. for the graphic text of a graphics list.
To create a text or graphics list, double-click in the project tree under the HMI project on Text and graphics lists. Create the text lists in the Text lists tab, and the graphics lists in the Graphics lists tab.
Double-click on <Add> in the table, and assign a meaningful name to the text or graphics list. Select the list type under Selection which defines how the tag linked to the list is to be interpreted:
b As Value/Range, then the text or graphic is displayed if the tag value is within the range or ranges
b As Bit (0, 1); a different text or graphic is then displayed for the signal states
“0” and “1”
b As Bit number (0 to 31); texts or graphics are then assigned to the individual bits.
Then define the list contents. Select the list and enter the values of the tags and the text or graphics in the Entries in text/graphics list table: Double-click on <Add> to open a drop-down dialog box which depends on the range selection for the text/graphics list:
b If Value/Range is selected, you can select Single value and enter the value or you select Range and specify the range; you can repeat this in the next lines with additional ranges or values
b If Bit is selected you can enter the texts/graphics for the signal states “0” and
“1”
b If Bit number is selected you can enter the texts/graphics for the bit numbers 0 to 31
By activating Standard in the entries of the selection Value/Range and Bit num- ber, you define the text or graphic to be output if the tag assumes an undefined value.
In the runtime settings under Screens you can define the response when several bits are set as the bit number: if the Bit selection for text and graphics lists check box is activated, the text or graphic that has been configured for a set bit with the least significance is shown. If the check box is not activated, the text or graphic that has been configured for a single set bit only is shown. If several bits are set, the text or graphic set as standard is then shown.
Working with function lists
System functions are predefined functions which cannot be changed, for example for calculating the value of a tag, for setting a bit in the PLC station, or for changing the user.
An HMI object may have configurable events, e.g. a button has the Click event.
A function list containing the system functions can be assigned to an event, which are then executed when the event occurs.
To configure a function list, select the object in the process screen and open the Events group in the Properties tab of the inspector window. Select an event, click in the function list on <Add function> and select the desired system function from the drop-down list.
It may be necessary to supply the system function with parameters. You can assign more than one system function to an event.