100/180 mm PAPERLESS GRAPHIC RECORDER: USER GUIDE
User Guide
Page 215
HA028910
Issue 13 Sep 16
4.5.1 NETWORK ADDRESS (Cont.)
IP ADDRESS
Allows manual entry of the recorder’s internet protocol (IP) address only if ‘Specify an IP address’ is se-
lected in the ‘IP address lookup’ picklist above.
Notes:
1. DHCP attempts to connect to the network continuously, until successful. Only when successful
will the network settings be updated and appear at the address page. This can take up to 13
seconds after power up.
2. It takes 2 to 3 minutes for a DHCP failure to be reported, so an instrument alarm would not be
generated for 2 to 3 minutes after power up, should the connection fail to be established.
SUBNET MASK
This fi eld is editable only if ‘Specify an IP address’ is selected in the ‘IP address lookup’ picklist above.
The subnet mask is the network address plus the bits in the host address reserved for sub-network identi-
fi cation. By convention, all the network address bits are set to 1. The subnet mask is used to identify the
subnet to which an IP address belongs by performing a bitwise AND on the mask and the IP address.
DEFAULT GATEWAY
To deliver traffi c from one subnet to another, devices called ‘routers’ or ‘gateways’ are placed between
segments. The default gateway address informs each network device where to send data if the target
station does not reside on the same subnet as the source.
SNTP SERVER ENABLE
This tick box allows the recorder to act as an SNTP time server.
SNTP CLIENT ENABLE
This tickbox allows time synchronisation from a Simple Network Time Protocol (SNTP) server to be ena-
bled and disabled. When enabled, the instrument time is updated every 15 minutes.
Note: SNTP always works using UTC/GMT. Time zones are handled separately.
SNTP SERVER
If ‘Obtain from BootP server’ or ‘Obtain from DHCP server’ is selected as the IP address look-up (see
above), then this address appears automatically. Otherwise this area allows an IP address to be entered
for the SNTP server.
Notes:
1 SNTP is a protocol that allows clients on a TCP/IP network to set their times to that of a server
- port number 123. The recorder can act both as a client and as a server; when acting as a
server, the resolution is 1 msec.
2. SNTP time is based on elapsed seconds since 00:00 hrs on 1st January 1900. The time is not
affected by time zones or daylight saving adjustments.
3. If the instrument time differs from the SNTP time by less than 2 seconds, the instrument time is
updated gradually (1 msec 8 times a second) to prevent time change events being recorded. If
the difference is greater than 2 seconds, this is defi ned as a ‘time change event’, the results of
which are that the recorder time is immediately updated, and a green line is drawn across the
chart (vertical/horizontal trend modes only) to indicate the time change.
4. If more than 5 time change events occur within 24 hours, a ‘Time Synchronisation failure’ instru-
ment alarm is set 24 hours after the fi rst event. Once synchronisation is re-established, the
alarm self-clears within 24 hours.
(Continued)
