JUMO 701061, Interface Description

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4 Data flow
4.1 Parameter addresses and formats
All process values (variables) together with their addresses, data type
and access mode are described below.
References are as follows:
R/O read access only
R/W read and write access
Text byte (8 bits)
unsigned
short
integer(16 bits), unsigned (value range 0 — 65535)
signed
short
integer(16 bits), signed (value range -32768 to +32767)
unsigned
long
long integer (4 bytes), unsigned
(value range 0 — 4294967295)
float float value (4 bytes) according to IEEE 754
Byte
sequence Because of the platform-dependent representation of floating-point
numbers and long values, the bytes must be arranged in the sequence
that is appropriate for Modbus.
4.2 Transmission formats
Character
strings (texts)
Character strings are transmitted in ASCII format.
Example Request the text from address 0x0007, when this address contains the
character string "
133.01.01 "
(ASCII code: 0x31, 0x33, 0x33, 0x2E, 0x30, 0x31, 0x2E, 0x30, 0x31, 0x20,
0x00)
Request: 0103000700067409
(CRC16 = 0974)
Response: 01030C 3133332E30312E3031200000 914D
(CRC16 = 4D91)
Integer values
When using Modbus, integer values are transmitted in the following format:
first the HIGH byte, then the LOW byte.
Example Request the integer value from address 0x0000, when this address contains
the value “20” (ASCII coding: 0x3230).
Request: 14030000000186CF (CRC16 = CF86)
H
A “\0” (ASCII code 0x00) must always be transmitted as the last
character, to mark the end of the string. Any subsequent characters
are meaningless.