UTC (Universal Time) functions

Both protocols use a standardized data format that refers to UTC (Coordinated Universal Time), and to no other time zones. They are used to synchronize timekeeping among a set of distributed time servers and clients.

RFC-868

RFC-1305

UTC: Setting/Synchronizing the Real Time Clock (RTC) via Ladder

Via VisiLogic's UTC functions, you can set the Real Time Clock (RTC) within an Ethernet-enabled Vision controller. Via Ethernet, you can:

Using RFC-868 to synchronize networked controllers

When a Vision receives a TCP request via Port 37, the Vision 'server' automatically sends its RTC time value to the requesting client device.

In the Vision 'server' :

Initialize the TCP/IP card and initialize a socket to TCP, Local Port 37, Slave as shown in the following figure.

When a Vision receives a TCP request via Port 37, the Vision automatically sends its RTC time value to the requesting client device.

In a Vision requesting the time:

Initialize the TCP/IP card and initialize a socket to TCP, Master.
Place a TCP/IP Connect function, set to Remote Port 37, as shown in the following figure.

When a Vision receives data via TCP request through Port 37, the Vision automatically sets its RTC, writing this value to all RTC SIs, 30 to 34.

Using RFC-1305 to synchronize a Vision's RTC to a UTC PC server

When a UTC PC server receives a UDP request via Port 123, the server automatically sends the time value to the requesting client device.

To request the data from the server, use the RFC-1305 function, located in Com>TCP\IP.

Initialize the TCP/IP card and initialize a socket to UDP.
Place the RFC-1305 function in the net, entering the PC server's IP address and the socket set in Socket Init. Note that the Protocol type and Port are set by default.

To write the time value received from the server into the controller and set the RTC, use the UTC to RTC function, located in Clock> UTC.

Link a positive transition contact to the RFC-1305 Function in Progress MB
Place a UTC to RTC function as shown in the following figure. Storing the UTC Resulting Value into SI 30 automatically writes the appropriate UTC values into all RTC SIs, 30 to 34, setting the RTC.

Clock menu	UTC to RTC The value in a DW is converted to a real-time clock format. Sending the value to SI 30 will set the controller's RTC by automatically overwriting SIs 30-34.
Clock menu	RTC to UTC Selecting SI 30 will convert the RTC value into a DW.
Com>TCP/IP menu	RFC-1305 Retrieves, via Ethernet UDP, the current time from a PC UTC server. This may be used to synchronize a Vision RTC with UTC.
HMI Clock Variables	Clock Display Variable, UTC This may be set as read only, or as a Keypad Entry variable used to set the RTC.

Note ♦	Note that these functions use the DW as a 32-bit binary number containing the UTC value in seconds, where 1900-01-01 = 00:00.00 UTC. Vision controllers support a range from 2004 to 2035.
♦	Since the DW is the value in seconds, you can perform time value calculations. For example, you can convert the RTC values to DWs, then calculate the difference in order to figure a time interval.

UTC (Universal Time) Functions

UTC: Setting/Synchronizing the Real Time Clock (RTC) via Ladder

Using RFC-868 to synchronize networked controllers

Using RFC-1305 to synchronize a Vision's RTC to a UTC PC server