User Manual

Chapter 7: Enabling and Using HART on the 1769sc-IF4IH0
U ser 's M a n u a l 0 300 21 5- 03 R ev. A
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•
HART channel device information is available.
RUNNING will be sent back when all of the following conditions are met:
•
Command and HART Cha nnel number are bot h valid .
•
HART channel is enabled and communication has been estab lished, meani ng at
least the device addressing information is available.
•
HART channel is already in the state of gathering device information. Reply
will be sent back without additional events triggered.
DEAD will be sent back if any of the following conditions is true:
•
Command or HART Chan nel number is invalid
•
HART channel is not enabled
•
HART communication has not been establis hed , meaning that the 5-b yte unique
address has not been determined yet.
•
All other conditioned not generating RUNNING or SUCCESS.
7.4.2 HART Channel Suspension and Resume
Sometimes referred to as "Out of Service" and "In Service" respectively, these commands
can be utilized to suspend or resume op e r ation of an enabled HART channel. When a
suspend H ART command is sent, the HART module will keep the current HART
configuration information and stop all communication processes on the selected channel.
However, there are overriding conditions such as a configuratio n change whic h can cause
the HART functio n to reset. Normal HART operation will resume if the resume HART
command is sent to the module during a HART suspension.
Note: The HART suspend and resume can be initiated b y setting a bit in the output
image. Refer to Chapter 6 for m ore details.
Note: If the resume command is received, without previously receiving a suspension
command, it will be ignored.
Note: The selected channel will resume normal HART operations three m inutes after
the suspension command has been received by the module. Pass-through for that
channel resets the time r to 3 minutes.
Table 7-12 (HART Suspend/Resu me)
HART Channel S uspend/Resume command request – co mmand message packet structure
Field Value Definition
HART Channel
Number
0x00 – 0x03 (1 byte)
0xFF (-1) Apply to all 8 channels
Enabled HART
channe l number
Command Number (1 byte)
0x05: Suspend (Set service mode)
0x06: Resume (Reset service mode)
The command
number to suspend
or resume