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VM600 networking manual MAVM600-NET/E 9 - 9

Edition 9 - February 2018

MPC4 card

SETTING UP A MODBUS CONNECTION (CPUM SW VERSION 071 OR LATER)

As can be seen from the analysis in Table 9-7, this line of the configuration file is used to

configure the channel 4 vibration data value of the AMC8 card located in slot 10 of the rack.

This parameter is available at the Modbus address 30003 as a 16-bit unsigned value by using

the Modbus function 04.

The parameter is a scaled value with a real-value range from −50.50 to 250.00. This

real-value range corresponds to the 16-bit unsigned (see 8.6.3 Analog values (registers))

value as follows:

The minimum FSD value of −50.50 is encoded as 0x0000 in the Modbus register

The maximum FSD value of 250 is encoded as 0xFFFF in the Modbus side.

As these are the minimum and maximum values, real-world values less than −50.50 will be

clipped to 0x0000 and values greater than 250 will be clipped to 0xFFFF.

NOTE: Unlike firmware version 067 or earlier, CPUM cards running firmware version 071

or later support non-symmetrical scaling values. That is, it is no longer necessary

for the magnitudes of the minimum FSD and the maximum FSD to be equal.

Table 9-8 illustrates reading the maximum 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 30004 and 30005.

= Equals

10 SlotNr Slot number

AMC8 CardType Analogue Monitoring Card with 8 channels

C4 Channel

VData value

Table 9-8: Reading minimum and maximum values example – second line

Data Syntax Description

30004 Address Modbus address

4 Function Modbus function

F DataType Data type

= Equals

MAX

30003

Table 9-7: Reading minimum and maximum values example – first line (continued)

Data Syntax Description

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