Rockwell Automation 1738-EXT1, EXT3 ArmorPoint Extension Units - Manual (Page 5)

Publication 1738-IN018A-EN-E - December 2004
ArmorPoint Extension Units, Series A 5
Extension Unit
Application Rules
All the following rules apply for both the 1738-EXT1 and 1738-EXT3
extension unit.
• For all adapters except the 1738-ADNX:
• Up to four extension units can be used per network adapter.
• For the 1738-ADNX adapter:
• Only one extension unit can be used if there are fewer than
32 modules on the backplane.
• The first module after an extension unit must be either a
1738-FPD or a 1738-EP24DC.
– A 1738-EP24DC is needed:
– if additional backplane power is needed because of
module current consumption, or
– after 2 extension units.
– A 1738-FPD is needed in all other configurations. The only
exception to this rule is if the modules in the segment after
the extension unit are only 1738-IT2IM12s, 1738-IR2M12s,
1738-OW4M12s, or 1738-OW4M12ACs. If only these modules
are used, no 1738-FPD or 1738-EP24DC is needed.
• The number or mix of modules you use between extension
cables does not matter as long as you do not exceed the rated
adapter or 1738-EP24DC current output.