Analog modules
9.3 SM 336; F-AI 6 x 0/4 ... 20 mA HART
Fail-safe signal modules
Installation and Operating Manual, 01/2010, A5E00085586-10
289
9.3.17.3
HART communication records
Transfer data records
HART communication can be controlled by one client per channel. Each channel has a
separate transfer area available. Each transfer area consists of the command and reply data
records.
Coordination rules for HART communication
●
Fixed data record numbers are assigned to each client/channel:
Channel
Client
Data record
0
Command
80
0
Reply
81
1
Command
82
1
Reply
83
2
Command
84
2
Reply
85
3
Command
86
3
Reply
87
4
Command
88
4
Reply
89
5
Command
90
5
Reply
91
●
After writing a command data record, a client has to read the reply data record before
writing another command data record.
●
From master class 2 (e. g.
SIMATIC PDM or the engineering system with PROFIBUS
master), the client can evaluate the "processing status" in the reply data record: If the
processing status is "successful" or "faulty", the data record contains current reply data or
error displays.
●
The data record must always be read in its entirety, since after it is first read with a
successful or faulty status, the data record can be changed by the module.
●
The status component in the reply data record (= HART status bytes) provides
information on whether and which errors have occurred.
