Delta RMC151 - Manual (Page 437)

6 Communication
Data registers in the response. Notice that the Packet
Length byte order is not affected by this field.
• Least-Significant Byte (LSB) First (00). For
example, the value 0x1122 will be encoded as 22
11.
• Most-Significant Byte (MSB) First (01). For
example, the value 0x1122 will be encoded as 11
22.
8-9 nn nn Starting Address (File). Gives the file number (f)
for the address (%MDf.e) to start the read at. The
order of the bytes in this 16-bit value is determined
by the Byte Order field.
10-11 nn nn Starting Address (Element). Gives the element
number (e) for the address (%MDf.e) to start the
read at. The order of the bytes in this 16-bit value is
determined by the Byte Order field.
12-13 nn nn Read Count. The number of 32-bit registers to read.
This value must be between 0 and 256. The order of
the bytes in this 16-bit value is determined by the
Byte Order field.
The RMC will respond to this request with the following packet:
Offset Data
(hex)
Description
0-1 nn nn Packet Length. Indicates the total length in bytes of
this packet, excluding this 2-byte field. This 16-bit
value is encoded with the least significant byte first.
2-3 00 02 Static Values. These bytes will always have these
values in the response.
4-5 nn nn Transaction ID. This value will echo the Transaction
ID in the request. It should be used to match this
response to the corresponding request.
6 94 -or- 54 Function Code (Response). If the read was
processed successfully, this byte will be 94, otherwise
it will hold 54.
7 nn Response Code. Indicates whether the read was
successful or not. See the DMCP Response Codes
section below.
8-… … Data. The values of each register that was read will
follow the above header. Each 32-bit value is encoded
in either LSB- or MSB-first byte order, as determined
by the Byte Order field. For LSB-first byte order, the
value 16#11223344 will be encoded as 44 33 22 11.
For MSB-first byte order, this will be encoded as 11
22 33 44.
Register Addresses
This protocol uses the RMC’s two-level file/element addressing format. The IEC Addressing
topic describes how this addressing format works.
DMCP Response Codes
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