Appendix J: Function Codes And Memory Maps; Modbus Memory Map Supplement; Totalisers; Input Text Message - Siemens SIREC D200 Manual

Appendix J: Function Codes and Memory Maps

Modbus Memory Map Supplement:

.
Start
Address Address
(Hex)
1800
1880
2400
18C0
1B00
NOTE:
1800 enter 1801.

Totalisers

Totaliser values in engineering units, 4 byte IEEE floats using 2 Modbus registers per
reading.

Input Text message

This facility allows a text message to be passed to the recorder to be annotated on the
chart and added to the message log. The maximum length of the message is 32 bytes of
ASCII characters, which need not be null-terminated.
It operates by utilising modbus function code 16 (0x10), Preset Multiple registers, and the
unique address 0x0004 in the modbus global register map
The Start Address will be 00 04, and the Byte Count of the number of bytes in the follow-
ing text message. As 2 modbus registers are used to pass an address to function 16, the
Number of Addresses has to be back calculated from the required Byte Count to give the
lowest integer such that (Number of Addresses) * 2
Count = 4, then Number of Addresses = 2, but if Byte Count = 5, Number of Addresses =
3.
As an example, to send the 5-character message Start to a slave address 02 the com-
plete message would be:
Slave Function
Address Code
02 10
The response follows the normal response for function code 16, and so to the above
message the response would be: 02 10 00 04 00 03 CRC CRC
43-TV-25-35 GLO Iss.4 Dec 06 UK
A5E01001767-04
End
(Hex)
185F Analogue Input Value (48 inputs max.)
18BF Communications Inputs (32 comms values max.)*
247F Extended Comms Inputs (64 comms values max.)*
197F
1B7F Totalisers (64 totalisers max.)
Some Modbus masters may require an offset of 1 for example instead of entering
Start Start No
Addr. Addr. Addr.
High Low High
00 04 00
Description
Pen Values (96 pens max.)
No
Byte
Addr.
Count
Lo
03 05 53
≥
= Byte Count. For example if Byte
Data CRC
74 61 72 74 CRC
CRC
CRC
265