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5.4.
RS485
COMMUNICATION VIA
M
ULTI
CONT
PROCESS CONTROLLER
5.4.1
Remote data query via HART
®
protocol
Knowing the HART commands of the transmitters, there is a possibility to query the data of the connected transmitters with the help of USER RS485 interface of
MultiCONT process controller (the MultiCONT acts as a bridge). This can be done the following way:
the MASTER inserts the HART frame to the data field of the HART frame, which is sent to the transmitters by the MultiCONT,
the MultiCONT unpacks the HART frame (received from the MASTER) and sends it to the transmitter,
the MultiCONT packs the HART answer of the transmitter and sends it to the MASTER in the data field of the HART frame.
The detailed description of remote programming can be found in the
“USER RS485 protocol for MultiCONT”
programming manual.
Designations: contents of the PA, SD and AD fields: see details in chapter 6.1. Command Structure*
MASTER
MultiCONT
(request)
Index:
list number of the transmitter.
PA SD AD
CD=241 (F1h)
BC=2h
CSD=232 (E8h)
Index=0
FCS(XOR)
In case of ‘Index
≠
0’ Index error will be sent in the answer!
MultiCONT
MASTER
(answer)
PA SD AD CD=241(F1h)
BC=48(30h) Status
S(0)
and S(1)
DATA D(0)…D(45) FCS(XOR)
The status bytes are described in details in chapter 6.1.1.*
The content of the DATA field:
B
YTE NUMBER
N
AME
D
ATA TYPE
N
OTE
0…3 MultiCONT
status
Bit32
4
CSD:
sub-command code
Unsigned 8
CSD = 232(E8h)
5
Index:
list number of the transmitter
Unsigned 8
Index = 0…Dn-1 (see 6.2.5.7. chapter)*
6
Number of sensors in a probe (1…15)
Unsigned 8
7
Dimension (Unit of measurement)
Unsigned 8
ºC = 32(20h) or °F=33(21h)
8…37
Sensor temperatures ×10, S1…S15 in order
Signed int 16
38…39
Transmitted Primary Value (PV) ×10
Signed int 16
(MAX, MIN, SELECTED SENSOR, AVG)
40…42
Date of last transmitter refresh
Date*
43…45
Time of last transmitter refresh
Time*
*
This chapter is in the “Description of the USER RS485 protocol for MultiCONT” programming manual.