140 NOE 771 x1 / 140 NOC 78• 00 IP Address Assignment
Original instructions
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Configuring a 140 NOE 771 •1 / 140 NOC 78• 00 Module
Since the primary and standby PLCs in a Quantum Hot Standby system have identical configurations, the configured 140 NOE 771 •1 / 140 NOC 78• 00 module IP addresses are the same. The current local Hot Standby mode determines the IP address.
This table shows how the 140 NOE 771 •1 / 140 NOC 78• 00 module IP addresses are assigned:
Hot Standby State
IP Address
primary CPU
IP address configured in Control Expert
standby CPU
IP address configured in Control Expert + 1
transition from primary to offline
IP address configured in Control Expert, if peer controller does not go to primary
transition from standby to offline
IP address configured in Control Expert + 1
IP Address Restrictions
Do not use either the broadcast IP address -1 or broadcast IP address - 2 to configure a 140 NOE 771 •1 / 140 NOC 78• 00 module.
For example, do not configure the primary CPU address as nnn.nnn.nnn.254. This causes the standby CPU IP address to be nnn.nnn.nnn.255. The standby CPU would then return the diagnostic code Bad IP configuration.
IP Address Transparency
WARNING
UNINTENDED EQUIPMENT OPERATION
For a Quantum Hot Standby configuration:
  • Do not use the IP address configured in Control Expert + 1.
  • Do not use consecutive IP addresses of the IP address configured in Control Expert.
Failure to follow these instructions can result in death, serious injury, or equipment damage.
When a switchover occurs, the new primary PLC takes the IP address of the old primary PLC.
When the PLC that has stopped becomes operational again and rejoins the Hot Standby system, it takes the IP address of the standby PLC.
The new primary 140 NOE 771 •1 / 140 NOC 78• 00 module has the same IP address as the former primary module. The IP address in the secondary module is IP address + 1.
The 140 NOE 771 •1 / 140 NOC 78• 00 modules integrated into the Quantum Hot Standby configuration coordinate this swapping of IP addresses with the management of Ethernet services used.
140 NOE 771 •1 IP Address Swap Time
The following table details the 140 NOE 771 •1 module IP address swap time:
Service
Typical Swap Time
Maximum Swap Time
swap IP address
6 ms
500 ms
I/O scanning
1 initial cycle of I/O scanning
500 ms + 1 initial cycle of I/O scanning
140 NOC 78• 00 IP Address Swap Time
The following table details the 140 NOC 78• 00 module IP address swap time:
Maximum swap time
500 ms (IP address swapping) + connection establishment time (3 s)
Recommended setting for implicit message
Set RPI to 1/2 of MAST cycle time (50 ms maximum)
Timeout multiplier setting for EtherNet/IP (EIP) scanner connections:
MAST Cycle Time (ms)
Recommended RPI (ms)
Timeout Multiplier
Connection Timeout (ms)
20
10
16
160
50
25
8
200
100
50
4
200
200
50
4
200
255
50
4
200
NOTE: The maximum swap time may increase if the end device does not respond in a timely manner.
NOTE: During the swap, there may be disruption in communication between the 140 NOE 771 •1 / 140 NOC 78• 00 module and the end device. Confirm that the application can tolerate this communication disruption.