Fluid Components Intl ST51A, Installation, Operation & Maintenance Instruction Manual

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OPERATION ST51A/ST75A/ST75AV Mass Flow Meters
40 Fluid Components International LLC
HART Command List Reference
The HART commands are divided into three classes.
● Universal Commands
● Common Practice Commands
● Device Specific Commands
Barring no communication error, a field or slave device returns a response code as part of the 2-byte status response to a command. Refer
to Command Status Bytes on page 52 . The ST51A/ST75A/ST75AV response codes listed in the following command summaries are a
subset of the response codes listed in the HART specification.
ST51A/ST75A/ST75AV HART Universal Commands
The ST51A/ST75A/ST75AV HART supports Universal Commands 0 through 22 and 38 and 48. Commands 4 and 5 are reserved under
Universal Command Specification Rev. 7.1 (HCF_SPEC-127, Revision 7.1) and not implemented in this specification. There is no HART
command 10. Table 12 below summarizes the instrument’s HART Universal command set and the data associated with each command.
Table 12 – HART Universal Commands
Command 0: Read Unique Identifier
Byte Format Description
Request Data Bytes None
Response Data Bytes 0 Unsigned-8 254
1–2 Enum Expanded Device Type
3 Unsigned-8 Minimum number of preambles from master to slave
4 Unsigned-8 HART Protocol Revision Number: 7
5 Unsigned-8 Device Revision Number
6 Unsigned-8 Software Revision Number
7 Unsigned-5 (Most Significant 5 Bits) Hardware Revision Level: 1
7 Enum Physical Signaling Code: 00 = Bell 202 Current (4-20 mA)
8 Bits Flags: 01 = Multisensor
9–11 Unsigned-24 Device ID
12 Unsigned-8 Minimum number of preambles from the slave to master
13 Unsigned-8 Maximum Number of Device Variables
14–15 Unsigned-16 Configuration Change Counter
16 Bits Extended Field Device Status
17–18 Enum Manufacturer ID Code: 166
DEC
/00A6
HEX
(FCI)
19–20 Enum Private Label Distributor Code
21 Enum Device Profile = 1 “HART Process Automation Device”
Response Codes: See Table 16 , page 53 , for response code list.
Command 1: Read Primary Variable (Flow Units, & Flow Value)
Byte Format Description
Request Data Bytes None
Response Data Bytes 0 Enum Primary Variable Units Code
1–4 Float Primary Variable Value
Response Codes: See Table 16 , page 53 , for response code list.
Command 2: Read Primary Variable Loop Current and Percent of Range
Byte Format Description
Request Data Bytes None
Response Data Bytes 0–3 Float Primary Variable Loop Current (mA)
4–7 Float Primary Variable Percent of Range (%)
Response Codes: See Table 16 , page 53 , for response code list.