Mitsubishi Electric MELSEC Q Series User Manual page 197

(4) Precautions
(a) Number of connections
Connections from multiple Telnet tools to the same C Controller module is not allowed.
Telnet tool must be connected to the C Controller module on a one-to-one basis.
Further, be sure close the Telnet tool being connected and connect another Telnet tool to the C Controller
module.
(b) Timeout
When the line is disconnected during Telnet connection, it takes 30 seconds before Telnet connection (TCP
connection) times out on the C Controller module. Telnet cannot be reconnected until it times out.
Timeout time may be changed by the (ipcom_sysvar_set) command provided by VxWorks.
• Obtaining timeout time
<Q24DHCCPU-V/-VG>
Timeout time = iptcp.KeepIdle value + (iptcp.KeepIntvl value  iptcp.KeepCnt value)
iptcp.KeepIdle: Interval from line disconnection to the first retry
iptcp.KeepIntvl: Interval between retries
iptcp.KeepCnt: Number of retries
• Program example
ipcom_sysvar_set("iptcp.KeepIdle", "XX", 1);
ipcom_sysvar_set("iptcp.KeepIntvl", "YY", 1);
ipcom_sysvar_set("iptcp.KeepCnt", "ZZ", 1);
ipcom_ipd_kill ("iptelnets");
ipcom_ipd_start ("iptelnets");
XX: Specify the time (in seconds). When this is specified to "0", no timeout will occur'
YY: Specify the time (in seconds). When this is specified to "0", no timeout will occur'
ZZ: Specify the number of retries
<Q12DCCPU-V>
Timeout time = net.inet.tcp.keepidle + ( net.inet.tcp.keepintvl  8 (number of retries) )
net.inet.tcp.keepidle: Interval from line disconnection to the first retry
net.inet.tcp.keepintvl: Interval between retries
• Program example
Sysctl("net.inet.tcp.keepidle = XXXXX");
Sysctl("net.inet.tcp.keepintvl = YYYYY");
XXXXX: Specify the time (in ms).
YYYYY: Specify the time (in ms).
CHAPTER 12 FUNCTIONS ACCESSED VIA ETHERNET PORTS
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