Schweitzer Engineering SEL-2032, Instruction Manual

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9.21
Date Code 20120126 Instruction Manual SEL-2032 Communications Processor
Protocols
Modbus RTU Protocol
message. If a legitimate message is received, but cannot be processed, the
SEL-2032 will respond with an error response, as indicated in the Message
Framing subsection above. The following is a list of possible exception codes:
01–ILLEGAL FUNCTION.
The received function code is not supported.
02–ILLEGAL DATA ADDRESS.
Some portion of requested registers is
undefined or invalid. For data writes, this may mean that the address is
read-only. For force single coil operations, the address is not the
beginning of a valid region.
03–ILLEGAL DATA VALUE.
The referenced data value in a force single coil
operation is not valid for the given coil.
04–FAILURE IN ASSOCIATED DEVICE.
The port accessed is not currently
collecting the desired data because of improper settings or because the
port is inactive or read from an empty region.
06–BUSY, REJECTED MESSAGE.
The SEL-2032 is unable to respond in a
timely fashion due to internal data access conflicts. Also, used to
indicate insufficient memory for requested operation.
Master Device Configuration Considerations
Modbus masters are capable of block requesting registers. Block requests of
data can be a problem, as described in the following example.
EXAMPLE 9.1 Block Requests
You want 5 registers starting at address 105, and another 5 registers
starting at address 205, and your Modbus master can request up to
125 registers. It will request 105 registers starting at address 105. The
SEL-2032 may not have data defined for all addresses between 100
and 200, and will declare the request invalid. To get these 10
registers, you must alter the maximum registers that your Modbus
master can request, or move the registers to a contiguous area of a
User region (using the SET M procedure) and request them at this
new address.
Register Maps
for Meter Data,
Integer Type
The example in Table 9.8 shows meter data mapped as 16-bit signed integers.
If a measured or calculated value exceeds the maximum value shown, the
register will contain the maximum value shown.
Table 9.8 Example Register Map for Meter Data, Integer Type (Sheet 1 of 3)
Reg.# Description Units Range
I. Data from Relays with ASCII Meter Format.
SEL-121D/221D:
100(R) Meter Date stamp Month 1–12
101(R) Meter Date stamp Day of the Month 1–31
102(R) Meter Date stamp Year 0–99
103(R) Meter Time stamp Hours 0–23
104(R) Meter Time stamp Minutes 0–59
105(R) Meter Time stamp Seconds 0–59
106(R) Meter Time stamp Milliseconds 0–999
Courtesy of NationalSwitchgear.com