Rockwell Automation T3488/T3488A ICS regent Monitored Guarded Output Modules - Manual (Page 7)

Monitored Guarded Output Modules (T3481/81A, 84 and 88/88A)
P D - 6 0 3 3 M a r - 0 6 (Issue 2)
7
When the module is installed in the I/O chassis or when logic
power (from the I/O power supply modules) is first applied to
the module, it will be in the shutdown mode until the first
output scan, regardless of the fault mode jumper settings.
Also, removing two I/O transceiver modules, two I/O power
supply modules, or two power legs will cause the module to be
in the shutdown mode. Note: