SMAR HI302, Руководство пользователя

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Advanced Configuration
4.2
Commands
See below some examples of HART commands and how to create a reading and writing
configuration for the variables. For a more detailed explanation, see the device manual.
We will use Universal Commands, although any HART command can be described the
same way.
Get the HART command documentation beforehand, as shown below:
Command 0 – Universal Identifier using polling address
Request Data Bytes
Byte Format Description
None
Response Data Bytes
Byte Format Description
0 Unsigned-8 “254”
1 Enum Manufacturer Identification Code.
2 Enum Device type.
3 Unsigned-8
Minimum number of Preambles required for the request
message from the Master to the Slave. This number
includes the two preambles used in asynchronous
Physical Layers (along with the Delimiter) to detect the
start of the message.
4 Unsigned-8
Universal Command Main Revision Number implemented
by this device. For HART Revision 6, this value must be
the number 6.
5 Unsigned-8 Device Revision Level.
6 Unsigned-8
Software Revision Level of this device. Levels 254 and
255 are reserved for special purposes.
Command 3 – Read the Loop current and up to 4 well-defined dynamic variable
Request Data Bytes
Byte Format Description
None
Response Data Bytes
Byte Format Description
0-3 Float Primary Variable Loop Current (units of milli-amperes)
4 Enum Primary Variable Units Code
5-8 Float Primary Variable
9 Enum Secondary Variable Units Code
10-13 Float Secondary Variable
14 Enum Tertiary Variable Units Code
15-18 Float Tertiary Variable
19 Enum Quaternary Variable Units Code
20-23 Float Quaternary Variable