Frequently Asked Questions

SystemLink Cloud Overview

What is SystemLink Cloud?
SystemLink Cloud is a cloud-based platform offered by NI. It enables you to securely access, monitor, and interact with applications from anywhere in the world without the burden of hosting and managing a server yourself. SystemLink Cloud hosts a suite of services, which includes a hosting service, a highly-scalable data service, a dashboard service, and data storage service. Access SystemLink Cloud with your NI User Account credentials and start enhancing your applications now.
How do I start using SystemLink Cloud?
Check out our Getting Started Guide for help.
Are there examples that show how SystemLink Cloud works?
The SystemLink Cloud team created an example to show you how SystemLink Cloud works. Let the Readme.md guide you through setting up, building, and hosting a web application on SystemLink Cloud.
What to see more? Check out our GitHub repository for more examples.

SystemLink Cloud Requirements

What software do I need to create applications that access SystemLink Cloud?
To build applications with APIs that communicate with SystemLink Cloud, you need to install one of the following product combinations with NI Package Manager:
If you do not have NI Package Manager, download and install the latest version now.
After you install the required products, launch LabVIEW, G Web Development Software or LabVIEW NXG Web Module and locate the SystemLink APIs on the Data Communication palette. If the SystemLink APIs are not there, you did not install them. To install them, refer to SystemLink API Installation for LabVIEW for more help.

API Key Info

What is an API key?
An API key authenticates an application trying to access SystemLink Cloud. It can be helpful to think of an API key like a username and password. When you log in somewhere, your username and password authenticate who you are and, if they’re correct, grant you access. An API key functions similarly for your application accessing SystemLink Cloud.
API keys are more secure than usernames and passwords because you can create and delete them on-demand. Furthermore, the only time you can see an API key is when you create it. So, keep it somewhere safe.
How do I create an API key?
Check out our Getting Started Guide to walk you through your first moments on SystemLink Cloud. Learn how to create your first API key and more there.
When should I use an API key?
Use an API key whenever you want to connect your application or WebVI to SystemLink Cloud from LabVIEW, G Web Development Software or LabVIEW NXG Web Module to make API calls.
Do I need to use an API key for web applications hosted on SystemLink Cloud?
It depends. If you want to host your web application on SystemLink Cloud, you can either delete the API key from your web application or keep it. If you plan to host your web appliaction on a third-party server, you must include the API key in your hosted web application in order to connect to SystemLink Cloud and communicate with SystemLink data services. You can limit access to the web application by creating a custom policy and assigning it to the API key.
Refer to the Hosting Authentication Credentials Securely section of Security in NI Web Technology for more information.
What happens if I lose an API key?
You can’t recover API keys. The only time you see an API key is when you create it. Therefore, consider saving your API key when you create it.
What is a policy, and how does it relate to an API key?
A policy is comprised of permissions, which define the actions an application can make against a resource. You then assign a policy to an API key, which then defines the limits of what an application using that API key can do.
Can I modify a policy and after I assign it to an API key?
Yes, you can change the policy permissions for the API key.
Any API call using an API key with the policy assigned immediately validates against the updated permissions.
How long does it take for a change in a policy to occur?
Policy reevaluation occurs every five minutes. Therefore, you must wait five minutes to see permission changes materialize in the application.

Tags and Messages

What are tags?
Tags are used to send pieces of low frequent data between distributed systems and applications. They are highly scalable, and SystemLink Cloud quickly syncs with them.
Use the Tag API to send and receive test and measurement data from one system to other systems, SystemLink Server, or SystemLink Cloud. Refer to the SystemLink Cloud API Docs to find out more.
What is a tag path?
Think of a tag path as structured way to idenity a tag. NI highly encourages using a period (.) as the tag path delimiter. You can set tag permissions based on the Tag path you enter in the Tag path field.
Note: Tag paths are character-sensitive.
What is a wildcard?
A wildcard is a symbol you use to replace one or more characters. On SystemLink Cloud, the wildcard is an asterisk (*).
What is wildcard syntax?
Wildcard syntax comes in handy when you want to set permissions for a group of tags, messages, or files, or query a collection of tags, messages, or files on SystemLink Cloud in one operation. To do this, you need to use the wildcard (*), which enables SystemLink Cloud to search for all tags, messages, or files that begin with the same characters preceding or following the wildcard symbol.
For example, to return every tag on SystemLink Cloud that begins with foo.bar, enter foo.bar* in the Tag path field. SystemLink Cloud then returns all tags that begin with foo.bar, regardless of the character differences after foo.bar.
What are messages?
Messages enable communication between systems using a publish-subscribe model. Use the Message API to send warning messages, status updates, or commands from one system to other systems. Refer to the SystemLink Cloud API Docs to find out more.
What is a message topic?
A message topic is a channel to which messages are published and subscribed to by endpoints, such as web applications. Set Message permissions for a single topic or multiple topics by entering the name of topic in the Message Topic field.
Note: Use the wildcard symbol if you want to set message permissions for multiple topics in the Message Topic field.
How do I limit access to specific tags?
Users can limit the tags an application may access within the settings of the policy assigned to the API key used by that application.
For example, you have an application where you want to allow read/write access to all tags that start with the path foo but want to have read only access to tags that start with the path bar. Check out the steps below for how to limit tags.
  1. Go to Security and click the Policies tab.
  2. Click + NEW POLICY.
  3. Name this policy Foo Read-Write.
  4. Select Read and Write as the tag permissions.
  5. In the Tag path, enter foo*.
  6. Make sure at least one of the Message permissions is selected and click Create.
  7. Create a new policy and name it Bar Read Only.
  8. Select Read as the tag permission.
  9. In the Tag path, enter bar*.
  10. Make sure at least one of the message permissions is selected and click Create.
  11. Switch to the API keys tab and click + NEW API KEY.
  12. Name the API key Example and select Foo Read-Write and Bar Read-Only as the policies.
  13. Click Create to limit access to specific tags for the application.

Web App Info

How do I host my WebVI on SystemLink Cloud?
Let the Getting Started Guide help you through the steps of hosting your web applications on SystemLink Cloud.
When I host my application on SystemLink Cloud, do I need to configure my Open Configuration API Key node a certain way?
If you want to use the policy attached to an API key for authorization include the server url and api key inputs. If you want to assign a policy to a web application directly leave the server url and api key inputs empty. You can then modify the policy by clicking on the gear icon next to the web application and selecting Modify security policy.
What is the difference between private, public, and shared web applications?

Dashboards Info

Where can I find documentation about Dashboards?
Check out the SystemLink Cloud Manual for documentation about Dashboards.
What is the difference between private, public, and shared dashboards?

Limitations

Why did my web app fail to upload?
Check out the Service Requirements section of this topic for more information.
How many tags, messages, files, tag history values, and hosted Web applications can I use or have?
Check out the Service Limits section of this topic for more information.

The Nitty-Gritty

Do I have to pay or have a license to access SystemLink Cloud?
How do I get G Web Development Software?
Purchase G Web Development Software on ni.com to start hosting your web applications on SystemLink Cloud.
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