Panasonic FP User Manual

NTP Server for PLC Clock Synchronization 

 

FP Web-Server V2.11 

140 

This function is used to synchronized the PLC clock with a network time server. 

 

For a detailed description of each field or button in the dialog, set the cursor into the field and 
press <F1> or highlight the button with <Tab> and press <F1>. 

In most LANs a Network Time Server (NTP or SNTP) is available to synchronize the real-time 
clock (RTC) and calendar date of the network units (computers). Such NTP servers provide 
accurate world date/time information in UTC format (Universal Time Coordinate).  

The FP Web-Server can request the current UTC time from the NTP server. Optionally the FP 
Web-Server can calculate the local time with a daylight saving time (DST) offset. And then the 
FP Web-Server can update the date/time RTC registers within the PLC. The update of the PLC 
clock can be done independently of the PLC program in constant time intervals.  

Additionally the FP Web-Server can be set up in this way so that a PLC-controlled internal relay 
can trigger a PLC clock update.  

The FP Web-Server can also save clock information in a user-definable DT register address. 
This is especially useful for PLCs having no integrated RTC. 

The time function is mainly designed to request the current time from an NTP server located in 
the LAN to update the PLC clock. "Example15" also shows how to dial up the Internet to request 
the time from an Internet NTP server to update the PLC clock. 

For more information on world time and DST see: 

•  http://www.worldtimezone.com/       
• http://www.twinsun.com/tz/tz-link.htm