Delta RMC151 User Manual
Page 462
RMC70/150 and RMCTools User Manual
2-3 mm mm
Packet Length. This value holds the number of 16-
bit words in this packet, not including this field and
the sub-header. For reading N registers from the
RMC, this register will hold 1+2xN, since each RMC
register uses 32 bits, or two 16-bit words.
4-5 nn nn
Read Count. This value holds the number of 32-bit
RMC registers that were read. This will match the
Read Count field in the read request.
6... ...
Data. The values of each register that was read will
follow the above header, with each register encoded
in 4 bytes ordered from the least- to most-significant
byte.
•
Finally, the client must acknowledge the RMC’s read response with the following
simple packet:
Offset Data
(hex)
Description
0
E0
Acknowledge. Indicates that the packet is an
acknowledgement.
1
00
Response Code. Indicates success (00).
Register Addresses
This protocol uses the RMC’s two-level file/element addressing format. See the IEC
Addressing topic describes how this addressing format works.
Response Codes
Each acknowledge packet holds a response code, indicating whether the requested
transaction was completed successfully or not. The RMC uses the following response
codes:
Response
Code
(hex)
Description
00
Success.
40
Protocol Error. Indicates that the request violated the
protocol described above in one of the following ways:
•
The Packet Length field was less than 3.
•
The Register File field was greater than 255.
•
The Register Element field was greater than 4095.
•
The length of the Data field in a write request was not
a multiple of 4 bytes.
•
The Read Count field in a read request was greater
than 382.
50
Bad Sub-header. A request packet did not start with 60 00.
Example 1: Writing a Single Register
In this example, the client will write the value 0x11223344 to variable 0 (%MD56.0).
Therefore, the Register File is 56, the Register Element is 0, and the Packet Length is
3+2xN or 5. Entering these values into the write request packet structure with the least-
significant bytes first, gives us the following packet:
60 00 05 00 00 00 38 00
00 00 44 33 22 11
442
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