Viper SC+™ IP Router for Licensed Spectrum PN 001-5008-000 Rev. C
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Table 19 Mnemonics and Data Types with Description for Allen-Bradley -Logix PLCs
Mnemonic
Data
Type
Description
UnconnectedTimeout
INT
Timeout for an unconnected message or for making a connection. The default value
is 30 seconds.
If the message is Then
Unconnected
The ER bit turns on if the controller doesn’t receive a response
within the UnconnectedTimeout time.
Connected
The ER bit turns on if the controller doesn’t get a response for
making the connection within the UnconnectedTimeout time.
ConnectionRate
INT
Timeout for a connected message once it has a connection. This timeout is
for the response from the other device about the sending of the data.
TimeoutMultiplier
INT
This timeout applies only after the connection is made.
The timeout = ConnectionRate × TimeoutMultiplier.
The default ConnectionRate is 7.5 seconds.
The default TimeoutMultiplier is 0 (which is a multiplication factor of 4).
The default timeout for connected messages is 30 seconds (7.5 seconds× 4 = 30
seconds).
To change the timeout, change the ConnectionRate and leave the
TimeoutMultiplier at the default value.
For the Logix controllers, the UnconnectedTimeout has to be individually adjusted in each message instruction tag. The
default is 30,000,000 microseconds (μsec or μs), or 30 seconds.
Figure 100 – MSG1 UnconnectedTimeout, ConnectionRate, and TimeoutMultiplier
When Communication Is Between ControlLogix or CompactLogix And Other –Logix Series PLCs
To lower the on-air traffic, uncheck Connected in the Message Configuration » Communication tab in the PLC setup.
The following figure shows an example when the Message Type is CIP Data Table Read or CIP Data Table Write. Note
that the Connected checkbox should be unchecked. This is because if you leave it checked, then every time the MSG
instruction is executed, a CIP connection (with CIP Open message) will be established and broken (with CIP close
message) which adds unnecessarily to the network traffic.
