Metrohm 857 Titrando - Manual (Page 18)

2 Installation
14 825 Lab Link, Instructions for Use
This is only intended for "debugging" in cooperation with Metrohm
Service.
Recommendation: Keep the Log-File Level as low as possible in
order to avoid unnecessary CPU and memory occupancy.
periodic status test
After the definition of a connection has been concluded (see Sec-
tion 2.6), the 825 Lab Link Server attempts to contact the corre-
sponding 825 hardware. All the defined Ethernet connections are
checked at regular intervals. The status test for an individual con-
nection consists of two parts:
a) an ICMP (Internet Control Message Protocol = "Ping") to the
corresponding TCP/IP address
b) an info-package request to the connected 825 hardware
The result of the status test directly determines the connection
status shown in column 3 of the server list (Connection status).
The status test cycle is defined in this input field. A short cycle pe-
riod enables a rapid reaction to status changes, but subjects the
network to a slightly greater load. A long cycle period lengthens
the reaction time to a newly switched-on 825 hardware, but re-
sults in less network traffic. The time must be selected so that the
Lab Link Server program always has the opportunity of opening
the TCP/IP connection to newly switched-on 825 hardware before
the Titrando system terminates the setting up of a connection to
the Lab Link Server. At the earliest, the connection setup takes
place 25 seconds after switch-on and is terminated after 50 sec-
onds at the latest with an error message if no connection is made
within this time. The following equation can be used as an aid for
calculating the optimal time:
periodic status test time
= 42 s - (no. of defined connections * ICMP timeout)
ICMP timeout
As described above, the periodic status test also includes a con-
nection from an ICMP (Internet Control Message Protocol) to the
corresponding TCP/IP address. If the target address does not re-
ply within the timeout period defined here then the connection will
be regarded as being non-existent.