Siemens TALON Series Technical Reference Manual page 49

Siemens Industry, Inc.
588-587
If too many of these outputs are configured, the voltage may drop too much so that all
modules switch off. When the voltage recovers, the modules switch on again, and so
forth, 1 to 2 times per second.
In this case, the TC Modular or TC-36 reacts by switching off the communication after
5 cycles (shortcut between CD and CS, the COM LED will light brightly).
CONFIDENTIAL: For internal use only
Troubleshooting the TX-I/O Island Bus
TALON TX-I/O Modules and Island Bus Technical Reference
49
4/6/2010