Rockwell Automation 1760-xxxx Pico Controller User Manual - Manual (Page 183)

Publication 1760-UM001D-EN-P - September 2005
Use of Expansion Modules 9-5
Module Status Example Power can be applied to the expansion unit later than it is applied to
the Pico controller. This means that Pico is switched to Run with the
expansion module missing. The Pico circuit diagram below detects
whether the expansion unit is operational or not.
As long as I14 = 1, the remaining circuit diagram is skipped. If I14 = 0,
the circuit diagram is processed. If the expansion module drops out
for any reason, the circuit diagram is skipped. M1 detects whether the
circuit diagram was processed for at least one cycle after the power
supply switched on. If the circuit diagram is skipped, all the outputs
retain their previous state. The next example should be used if this is
not desired.
Example with LCD Output and Reset of the Outputs
-----------SM1
I14--------[:8
I1-I2------[Q1
Q1
I14-M1-----[:8
-----------SM1
I14--------[:8
I1-I2------[Q1
Q1
I14-M1-----[:8
I14--------[:8
:8---------[D1
RQ1
:8
I14--------[D1