Sntp Client (Msntp) - WAGO 750 Series Manual

4.5.4 SNTP Client (msntp)

The msntp program provides SNTP client functionality.
SNTP (Simple Network Time Protocol) is a simplified version of NTP
(Network Time Protocol). SNTP allows communication with a remote SNTP
server via UDP frame and port 123. If you want to connect to an SNTP server
on the Internet, routing and the firewall must be configured accordingly.
SNTP transmits time as a 64 bit value, i.e. it has a resolution of approx. 0.25
ns. The accuracy of time transmission is said to be +/-10 ms on the Internet
and up to +/-200 μs in local networks (Marzullo's algorithm, by Keith
Marzullo, University of San Diego).
To get the time from an SNTP server, start msntp as follows:
msntp <Hostname/IP-Adresse>
Examples:
msntp 192.168.1.11
msntp WagoLFBC
The output is, for example:
2005 Aug 31 06:44:41.897 – 94504 +/- 34 secs
First, the date and the time of the time server are shown. The following
number is the deviation (in this case -94.504 seconds). The last number
indicates the jitter. The more the network is loaded or the farer away the time
server is, the bigger the jitter becomes.
Msntp can also directly change the time of the local system:
msntp -r <Hostname/IP-Adresse>
Example:
The output is, for example:
The correction time is 94.493 +/-0.33+0.045seconds
Do you want correct the time anyway?
If you enter y, the time in the RTC chip and in the Linux kernel is changed via
the internal function
previous query.
WAGO-I/O-SYSTEM 750
Linux Fieldbus Coupler
msntp -r 192.168.1.11
settimeofday()
Board Support Package (BSP)
Ethernet Interface Services
using the correction value of the
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