ProSoft Technology MVI69-HART - Manual (Page 160)

Reference MVI69-HART ♦ CompactLogix Platform
User Manual HART Multi-drop Master Communication Module
Page 160 of 169 ProSoft Technology, Inc.
March 29, 2012
5 For multi-drop applications, the 1KΩ resistor should be normally used when
one transmitter is connected to the port. If you increase the number of
devices connected to a single port, you may need to reduce the size of the
resistor.