9.18
SEL-2032 Communications Processor Instruction Manual Date Code 20120126
Protocols
Modbus RTU Protocol
Send a coil ON (operation code FF00h) to set the bit and OFF (operation code
0000h) to clear the bit.
Preset Single Register (Function Code 06h)
The SEL-2032 uses this function to allow a Modbus master to write directly to
a database register. Section 6: Database shows which registers are writable
and defines their operation. If you are accustomed to 4X references with this
function code, for 6-digit addressing simply add 400001 to the standard
database addresses.
The master request must have the following format:
1 byte. Slave Address
1 byte. Function Code (06h)
2 bytes. Register Address
2 bytes. Data
2 bytes. CRC–16 for message
A successful SEL-2032 response is an echo of the request message.
Preset Multiple Registers (Function Code 10h)
This function code works much like code 06h, except you can write multiple
registers at once, up to 120 per operation. Normally, this function code will
only be used in the User region. If you are accustomed to 4X references with
the function code, for 6-digit addressing simply add 400001 to the standard
database addresses. The master request must have the following format:
1 byte. Slave Address
1 byte. Function Code (10h)
2 bytes. Starting Address
2 bytes. Number of registers to write
1 byte. Byte count (should be twice number of registers)
n bytes. Byte count bytes of data
2 bytes. CRC–16 for Message
A successful response has the format:
1 byte. Slave Address
1 byte. Function Code (10h)
2 bytes. Starting Address
2 bytes. Number of Registers
2 bytes. CRC–16 for Message
Report Slave ID (Function Code 11h)
The SEL-2032 identifies the port device type when it receives this request. It
also provides information on how data is being collected from an SEL relay so
the specific map to use can be determined.
Courtesy of NationalSwitchgear.com
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