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Rockwell Automation 2711E PanelBuilder 1400e Modbus Communications User Manual

Page 42

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6–5

Defining Tags

Publication 2711E-6.12 – August 1997

Data Type
Select the data type that matches the format of the data stored in
the controller. The default entry in the data type field is Default.
In Modbus applications, the Default data type is Unsigned Integer
with an address length of 16 bits. Unless special data is expected,
Default should be acceptable.

The following data types are supported for Analog tags in a
Modbus application:

Data Type

Description

Default

Unsigned 16-bit value.

Byte

Unsigned 8-bit value. Uses the lower 8 bits of the 16-bit
address.

Unsigned Integer

Unsigned 16-bit value.

Integer

Signed 16-bit value.

Long Integer

Signed 32-bit value.

Bit Position

Value range from 0 to 16. Address length fixed at 16 bits.

1 BCD

Value range 0 to 9. Uses lower 4 bits of 16-bit address.

2 BCD

Value range 0 to 99. Uses lower 8 bits of 16-bit address.

3 BCD

Value range 0 to 999. Uses lower 12 bits of 16-bit address.

4 BCD

Value range 0 to 9999.

Floating Point

Single-precision (32-bit) floating point value. The range of data
values is –3.402823E +38 to –1.175494E –37, 0, and
+1.175494E –37 to +3.402823E +38.

BIN 3

Value range 0 to 999. Uses a 16-bit address.

BIN 4

Value range 0 to 9999. Uses a 16-bit address.

BIN 6

Value range 0 to 999999. Uses a 32-bit address.

BIN 8

Value range 0 to 99999999. Uses a 32-bit address.

Initial Value
This is the default value of the tag at the terminal. When a tag is
used with a PanelBuilder input object or function, this initial
value, after descaling, is written to the controller when the
application first executes.

For a PanelBuilder object with an initial state and a main control
tag, the object’s initial state value supersedes the tag’s initial
value, so that the initial state value is written to the controller
instead of the tag’s initial value. On application upload, the
object’s initial state value is used as the tag’s initial value.

Note: For the PanelView terminal to write default values to the
controller, you must choose No for “Use Default Operation,” on
the terminal’s Application Startup screen, and you must cycle
power to the terminal. Default values are written to the controller
whenever you subsequently cycle power to the terminal.

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