Modbus Memory Map Supplement; Input Text Message; Appendix J: Function Codes And Memory Maps; Totalisers - Honeywell X Series User Manual

Appendix J: Function Codes and Memory Maps

Modbus Memory Map Supplement:

Refer to document Modbus
Start
Address
(Hex)
1800
1880
2400
18C0
1B00
* Communications Inputs can be set by using Modbus function code 16
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 (Table A-1)
The modbus message format follows that shown in section 3.7 of the document cited.
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 given in section 3.7, and
so to the above message the response would be: 02 10 00 04 00 03 CRC CRC
43-TV-25-30 Iss.6 GLO Aug 07 UK
End
Address
(Hex)
185F Analogue Input Value (48 inputs max.)
18BF Communications Inputs (32 comms values max.)*
24BF Extended Comms Inputs (96 comms values max.)*
197F
1B7F
Some Modbus masters may require an offset of 1 for example instead of entering
Start Start
Addr. Addr. Addr.
High Low High
00 04
®
Serial Communications User manual, 51-52-25-66P, 04/06.
Description
Pen Values (96 pens max.)
Totalisers (64 totalisers max.)
No No
Byte
Addr.
Count
Lo
00 03 05
Appendix
51-52-25-66P
≥
= Byte Count. For example if Byte
Data
53 74 61 72 74
See
A.5
A.6
A.6
A.7
A.9
CRC CRC
CRC CRC
303