Canvas uses JavaScript ES5 for scripting. Nearly all objects and functions that are supported in ES5 are available. For a complete list of supported features, see the ES5 specification: https://262.ecma-international.org/5.1/.
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Below is a list of the built-in functions provided by Canvas.
alarm
Provides a way to interact with Gateway alarms.
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// Write a CSV to a USB drive. Only contains alarms with the label "myLabel"
alarm.createCsv("myLabel", Storage.Usb); |
datalog
Provides a way to interact with Gateway data log models.
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// Store a CSV with the past hour of data to an SD card
var current = new Date(Date.now());
var past = new Date(current);
past.setHours(past.getHours() - 1);
datalog.createCsvForRange("myModel", past, current, Storage.Sd); |
keyboard
Allows for sending keyboard events and bringing up keyboard popups for inputting values.
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// Edit a string tag with custom display options
keyboard.launchKeyboard("stringTag", {"header": "Setting OtherTag", "x": 100, "y": 200}); |
notification
Provides a way to interact with the notifications system.
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// Send a notification that automatically dismisses itself after 3 seconds
notification.send("Hello for a moment.", 3000); |
page
Allows for manipulation of project pages and the current page.
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// If the page "WarningPage" is currently open, open the page "WarningPopupPage"
// Otherwise, open the page with index 1
if (page.currentName() == "WarningPage") {
page.open("WarningPopupPage");
} else {
page.openIndex(1);
} |
schedule
Provides a way to enable and disable schedules.
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// Toggle whether the schedule "mySchedule" is enabled
schedule.setEnable("mySchedule", !schedule.isEnabled("mySchedule")); |
Storage
The Storage object allows you to specify a location for saving various data within scripts. Either the numerical value (0, 1, 2, 3) or the enum value (Storage.Invalid, Storage.Local, Storage.Usb, Storage.SdCard) may be used whenever a storageType argument is required.
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// Store a data log CSV to the HMI
datalog.createCsv("model", Storage.Local); |
system
Provides a way to interact with the runtime application.
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// Exit the runtime and stop the project system.exit(); |
tag
Allows for the manipulation of tags.
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Note: See the Reading and Writing Tag Values section for more information.
thread
Pauses the script for a specified amount of time. Only affects the calling script’s thread.
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// Gradually increase a tag value from 0 to 10 over the course of 1 second
var value = 0;
while (value < 10) {
tag.write("myTag", value);
value += 1;
thread.msleep(100);
} |
Rapidly writing tag values may cause performance issues, especially when using tags that are not local to the runtime.