User manual

Reference MVI56-HART ♦ ControlLogix Platform
User Manual HART Multi-drop Master Communication Module
Page 94 of 171 ProSoft Technology, Inc.
October 13, 2011
Point-to-Point Mode
Important: If the HART device address is 0 you must configure the channel for
Point-to-Point mode.
In point-to-point mode, the module only polls for a single instrument with a polling
address of zero. When the instrument is found by the channel, it continuously polls for the
data using command 3. Occasionally, it will poll for the configuration information for the
device. This is accomplished with HART commands 13, 14 and 15. Less frequently, the
channel will perform a HART command 0 request to see if any of the data for the
instrument has changed. If communications is lost with the device, the module will try to
establish communications with the device using command 0. If user commands are
present and enabled, they will be executed after each data poll.
When the point-to-point mode of auto-polling is enabled (Auto-Poll Code = P), the
following diagram applies to the channel operation: