Poll interval, Reg count, Swap code – ProSoft Technology MVI56E-MNETR User Manual

Page 60

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MVI56E-MNETR ♦ ControlLogix Platform

Configuring the MVI56E-MNETR Module

Modbus TCP/IP Interface Module with Reduced Data Block

User Manual


Page 60 of 153

ProSoft Technology, Inc.

August 31, 2009

Poll Interval

0 to 65535

This parameter specifies the minimum interval to execute continuous commands
(Enable code of 1). The parameter is entered in tenths of a second. Therefore, if
a value of 100 is entered for a command, the command executes no more
frequently than every 10 seconds.

Reg Count

Regs: 1 to 125

Coils: 1 to 800

This parameter specifies the number of 16-bit registers or binary bits to be
transferred by the command.

ƒ Functions 5 and 6 ignore this field as they apply only to a single data point.
ƒ For functions 1, 2, and 15, this parameter sets the number of bits (inputs or

coils) to be transferred by the command.

ƒ For functions 3, 4, and 16, this parameter sets the number of registers to be

transferred by the command.

Swap Code

No Change

Word Swap

Word and Byte Swap

Byte Swap

This parameter defines if and how the order of bytes in data received or sent is to
be rearranged. This option exists to allow for the fact that different manufacturers
store and transmit multi-byte data in different combinations that do other
manufacturers. This parameter is helpful when dealing with floating-point or other
multi-byte values, as there is no one standard method of storing these data
types. This parameter can be set to rearrange the byte order of data received or
sent into order more useful or convenient for other applications. The following
table defines the valid Swap Code values and the effect they have on the byte-
order of the data.

Swap Code

Description

None

No Change is made in the byte ordering (1234 = 1234)

Swap Words

The words are swapped (1234=3412)

Swap Words & Bytes

The words are swapped then the bytes in each word are swapped
(1234=4321)

Swap Bytes

The bytes in each word are swapped (1234=2143)

These swap operations affect 4-byte (or 2-word) groups of data. Therefore, data
swapping using these Swap Codes should be done only when using an even
number of words, such as when 32-bit integer or floating-point data is involved.

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