DB80: Compact message format
Byte Initial value (hex) Comment (Hex)
0 20 Req_Control
(20 = Compact message format
60 = Compact message format with SHC string)
1 05 Number of preamble bytes (5…20, 255)
2 01 Command (CMD)
3 00 Length in bytes
You can learn when the response from the eld device was received by cyclically reading data
record DS81 for HART channel 0. The response is always supplied in transparent message format.
FC81: Read the response with SFB 52 to DB81
Explanation
m3: CALL SFB52, DB52
REQ :=M1 Read request
ID :=DW#16#200
INDEX :=81
Module address
Data record number 81
MLEN :=200 Target length
VALID :=M49.7
BUSY :=M49.1
ERROR :=M49.6
STATUS :=MD100
LEN :=MW104
RECORD :=P#DB81.DBX0.0 BYTE 200
A M 49.1
SPB m3
BE
Block status or error information
Target area in DB81
The program part A M 49.1 to SPB m3 is only required if reading is to occur within a block cycle.
As long as the processing status (byte 0 of DB81) is at 3 (waiting, executing), the response has
not yet been received from the eld device. As soon as the processing status changes to greater
than 3, the HART request is nished.
With a processing status of 4, the request nished without errors and the response data can be
evaluated.
With a processing status of 5, the request also nished without errors but without response data
from the eld device.
With a processing status of 6 or 7, the request nished with errors. You can nd more detailed
information in byte 1 of DB81 (see table "HART group fault display") and for a HART protocol error
also in byte 2 of DB81 (see table "HART protocol error during response").
HART operating data records
A.3 HART request and response data records
F-AI 8xI 2-/4-wire HART HA
102 Equipment Manual, 09/2021, A5E50557845-AA
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