in reply to: HART Multi-drop network posted by Zaheer on 04 July 2013 at 07:29:52.
Presumably you have correctly allocated different non-zero polling addresses to each HART device before connecting them in multidrop.
Are all the HART devices set to park their loop current? Are any of the devices HART rev. 6 or 7? Or the gateway? (Rev. 6 introduced a change to command 6 used to set the polling address and current mode, but all devices should retain compatibility.)
I am thinking maybe you run out of power to the extra field devices; have you measured the total loop current and supply voltage?
What is the make and model of the HART/Ethernet gateway? And of the field devices?
What is the total length of cable on the multidrop network?