Schweitzer Engineering Laboratories SEL-749M, Инструкция по эксплуатации

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D.6
SEL-749M Relay Instruction Manual Date Code 20080918
Modbus RTU Communications Protocol
Communications Protocol
The Parameter Descriptor field is defined in Table D.13 :
The Parameter Conversion field is defined in Table D.14 :
A successful response from the slave will have the following format:
1 byte Slave Address
1 byte Function Code (60h)
2 bytes Parameter Number
1 byte Parameter Descriptor
1 byte Parameter Conversion
2 bytes Parameter Minimum Settable Value
2 bytes Parameter Maximum Settable Value
2 bytes Parameter Default Value
2 bytes CRC-16
Table D.13 60h Read Parameter Descriptor Field Definition
Bit Name Description
0 RO: Read-only 1 when the setting is read-only
1 H: Hidden 1 when the setting is hidden
2 DBL: 32-bit 1 when the following setting is a fractional value of this setting
3 RA: RAM-only 1 when the setting is not saved in nonvolatile memory
4 RR: Read-only
if running 1 when the setting is read-only if in running/operational state
5‘ P: Power Cycle
or Reset 1 when the setting change requires a power cycle or reset
6 0 Reserved
7 Extend Reserved to extend the descriptor table
Table D.14 60h Read Parameter Conversion Field Definition
Conversion Value Type Multiplier Divisor Offset Base
0 Boolean 1 1 0 1
1 Unsigned Integer 1 1 0 1
2 Unsigned Integer 1 10 0 1
3 Unsigned Integer 1 100 0 1
4 Unsigned Integer 1 1000 0 1
5 Hexidecimal 1 1 0 1
6 Integer 1 1 0 1
7 Integer 1 10 0 1
8 Integer 1 100 0 1
9 Integer 1 1000 0 1
10 Enumeration 1 1 0 1
11 Bit Enumeration 1 1 0 1
Table D.12 60h Read Parameter Information Command (Sheet 2 of 2)
Bytes Field
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