NIVELCO THERMOPOINT TM/J-500, Руководство пользователя и программирования

Страница: 24 / 28

24 / 28

tmh5554a0600p_06

tmh555en2106p
5.4.2 Remote data query with MODBUS 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 MODBUS 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 Modbus frame.
The detailed description of remote programming can be found in the “USER RS485 protocol for MultiCONT” programming manual.
Designations: ADDR, FNC and BCNT fields: see details in chapter 6.1. Command Structure*
MASTER

MultiCONT (request)
ADDR FNC=03h
START QUANTITY CRC
7000h+N*0040h+00…14h HI=00h LO=01h…16h HI LO
N=0…Dn-1, where Dn is the number of the HART devices (see: Table of system variables 0012h address)*
MultiCONT

MASTER (answer)
ADDR FNC=03h BCNT (byte number)
DATA bytes in the read address
B(0)…B(BCNT-1)
CRC
HI LO
B
YTE NUMBER
N
AME
D
ATA TYPE
N
OTE
7000h Number of sensors in a probe (1…15) Unsigned 16
7001h Dimension (unit of measurement) Unsigned 16 ºC or °F
7002h S1 Sensor temperature×10 Signed Int 16
7003h S2 Sensor temperature×10 Signed Int 16
…
Sn Sensor temperature ×10 Signed Int 16
700Fh S14 Sensor temperature ×10 Signed Int 16
7010h S15 Sensor temperature ×10 Signed Int 16
7011h Transmitted Primary Value (PV) ×10 Signed Int 16 (MAX, MIN, SELECTED SENSOR, AVG)
7012h Date of last table refresh Date*
7014h Time of last table refresh Time*
* This chapter is in the “Description of the USER RS485 protocol for MultiCONT” programming manual.