Rockwell Automation 1732DS-IB8 User Manual page 14

10 About the Modules
Publication 1791DS-UM001H-EN-P - April 2009
For 1791DS-IB4XOW4 modules, follow these instructions on isolating
transformer use. Refer to the isolating transformer figure.
Use an isolating transformer to isolate between over-voltage
category III and II, such as TR1, to conform to IEC 60742.
Be sure the insulation between first input and secondary output
satisfies at least basic insulation of over-voltage category III.
Be sure one side of a secondary output of the isolating
transformer is grounded to prevent electric shock to personnel
due to a short to ground or short to the frame of the isolating
transformer.
Insert fuses, in case of a short to the frame, to protect the
isolating transformer and prevent electric shock to personnel,
per transformer specifications, at points such as F1, F2, and F3.
Use of Isolating Transformer
400V ac/ 230V ac
L1 L2 L3
F1
F7 F8
F6
F2
MA
MB
Load
III
1791DS-IB4XOW4
F4
F3
TR1
F1...F8 - Fuses
MA, MB - Electromagnetic Switches
TR1 - Insulated Transformer
Over-voltage Category
F5
MB
MA
44151
II