Corrected Anomaly with Firmware Revision 20.022

Known Anomaly First Identified as of Firmware Revision 20.013

Catalog Numbers:

• 1756-CN2/B
• 1756-CN2R/B
• 1756-CN2RXT/B

When a 1756 discrete output module using a rack-optimized connection in a remote chassis establishes a connection, outputs briefly transition to a random non-commanded state. This time period starts when a new connection is established and ends when the first data is received from the controller.    

A connection is established by one of the following:

• Downloading a project to the controller
• Cycling power
• Inhibiting/uninhibiting the communication bridge or adapter in the Logix application
• Making the initial connection (first-time connection)
• Reconnecting after a network cable break

Rack-optimized connections are made by configuring the communication adapter rack connection to ‘Rack Optimization’. This configuration is done in the I/O configuration of RSLogix 5000^® or Studio 5000^® programming software. To use a direct connection, set the rack connection to ‘none’.

Channel faults (Late clock lock) (Lgx00186820)

Corrected Anomaly with V20.022

Known Anomaly First Identified as of Firmware Revision 20.009

Catalog Numbers:

• 1756-CN2/B
• 1756-CN2R/B
• 1756-CN2RXT/B

A rare combination of conditions, including multiple noise sources coupled onto the ControlNet cable, can occasionally result in a module failing to lock onto the preamble within 16 bit times when the edges of the incoming data and the local sample clock initially coincide.

These conditions occur infrequently and cause one packet to be lost. No data is corrupted and no connections are dropped.

Changing the edge detector to run at twice the sample rate significantly improves the ability of the module to sense the preamble when these conditions occur.

Cycle Power to Unit: Assert in File CnetSchedTransmitList.cpp Line 258 (Lgx00176648)

Corrected Anomaly with V20.022

Known Anomaly First Identified as of Firmware Revision 20.013

Catalog Numbers:

• 1756-CN2/B
• 1756-CN2R/B
• 1756-CN2RXT/B
  

While running RSLogix 5000^® V20.00.00 and RSNetWorx™ for ControlNet 21.01.00 application software, the ControlNet bridge faulted as described above.

Fixed the mutex lock.