9 - 10 VM600 networking manual MAVM600-NET/E
Edition 9 - February 2018
MPC4 card
SETTING UP A MODBUS CONNECTION (CPUM SW VERSION 071 OR LATER)
Table 9-9 illustrates reading the minimum channel scaling value using Modbus. The value is
coded as an F data type (and therefore only available) as floating so it requires two
consecutive 16-bit addresses. The values are available using Modbus function 04 at
addresses 30006 and 30007.
9.4.1.2 Constant values
It is possible to set Modbus addresses to constant values. Constants can be set for the
following data types:
• B (1-bit value)
• F (32-bit floating value)
• U (16-bit unsigned value).
Examples:
Data from the mapping section of a typical configuration file:
30004:1:B=1
Valid values for data type B are 0 or 1.
30005:4:F=10.0
Valid values for data type F can be any 32-bit floating-point value.
30004:4:U=1234
Valid values for data type U are between 0 (0x0000) and 65535 (0xFFFF).
9.4.1.3 Bit variables
It is now possible for the user to define bit variables.
Table 9-9: Reading minimum and maximum values example – third line
Data Syntax Description
30006 Address Modbus address
4 Function Modbus function
F DataType Data type
= Equals
MIN
30003
4