Real-Time Clock (RTC) Synchronization
Technical Note 5083
Applicable Model(s)
HMI5000 Series
cMT Series
Title
Real-Time Clock (RTC) Synchronization
Date
01/20/2023
Rev
02
P/N
0907-5083
Summary
There are times when it is advantageous for the RTC (Real-Time Clock) in the HMI to be synchronized with an external device such as a connected PLC. Also, it may be required to sync the HMI’s RTC to a specific time zone using a NTP (Network Time Protocol) server, or simply synchronized with the local time and date of the development PC.
Solution
There are several ways to synchronize the HMI’s internal RTC with an external RTC. You can use the HMI’s System Parameter Settings, use a Data Transfer Object, or sync with the development PC when the project is downloaded into the HMI. The following pages provide details on each of the available options.
Using Network Time Protocol (NTP) Server
Note: To successfully sync with the NTP Server, the HMI must be granted outside internet access when it is in operation. Always adhere to your Company guidelines for Information Technology best practices and procedures as it relates to granting devices access to the internet.
The System Parameters menu has a Time Sync./DST tab that will allow the HMI to maintain its RTC sync with a Network Time Protocol (NTP) Server.
1.
Under the Home menu select System Parameters…
2.
Select the Time Sync. / DST tab.
3.
Enable time sync by checking the Enable check-box.
4.
Enter the address of the NTP Server(s) you want the HMI to sync up with, and the update interval (in seconds). A list of public NTP servers can be readily found at the National Institute of Standards and Technology (NIST) website.
5.
Enter the Daylight Saving Time (DST) option if desired.
5.
Click OK to exit the System Parameter Settings window.
Data Transfer Object (Trigger-based)
To update the RTC more frequently than one-time at startup, or if the HMI does not have outside internet access, you can use a Data Transfer Object. This Data Transfer can be either Trigger-based or Time-based depending on the application.
NOTE: Data Transfer Objects can be either Per-page or Global. Per-page objects are active only when the window they are placed on is the active window in the project. By contrast, Global objects are always active, and will perform actions regardless of which window is currently open. In the examples below we will use the Global object.
1.
Select Data Transfer (Global) under the Objects menu.
2.
Select the Bit Trigger tab at the top of the window.
3.
Click New… to create a new Data Transfer Object.
4.
The following window will be displayed:
In the Source address section, select the address in the external device that holds the first of the RTC values. The RTC values in the external device must be consecutive and in the following format:
Address = local second (0-59)
Address+1 = local minute (0-59)
Address+2 = local hour (0-23)
Address+3 = local day (1-31)
Address+4 = local month (1-12)
Address+5 = local year (0-9999)
5.
In the Destination address section, select the Local HMI system tag LW-9017 (16bit): local second.
6.
In the Attribute section input a 6 into the No. of word: input field.
7.
Select Touch trigger or External trigger depending on the application.
8.
Click OK and place the Object on the Window.
Data Transfer Object (Time-based)
1.
Select Data Transfer (Global) under the Objects menu.
2.
Click the New… button.
3.
The following window will be displayed:
4.
Under the Attribute section select Word for the Address type.
5.
Select the Interval, or time in between Data Transfers.
6.
Next to No. of word: input a 6.
7.
In the Source address section, select the address in the external device that holds the first of the RTC values. The RTC values in the external device must be consecutive and in the following format:
Address = local second (0-59)
Address+1 = local minute (0-59)
Address+2 = local hour (0-23)
Address+3 = local day (1-31)
Address+4 = local month (1-12)
Address+5 = local year (0-9999)
8.
In the Destination address section, select the Local HMI system tag LW-9017 (16bit): local second.
9.
Click OK.
Sync with Development PC
When downloading a project to the HMI with EBPro (or EZwarePlus v5.05.02.114 or newer), you can easily adjust the HMI’s time and date to match with the development PC.
1.
Under the Project menu, select Download.
2.
Select the Synchronize HMI clock with PC check box in the lower half of the Download window.
3.
Choose any other download options by selecting / deselecting the appropriate check boxes.
4.
Click the Download button to commence download to the HMI. The HMI will show the progress of the download in the top portion of the Download window.
5.
When the HMI reboots, its RTC time and date will be updated with the information from the PC.