Determining rack and block transfer needs, Planning your application chapter 4 – Rockwell Automation 2711 PANELBUILDER SOFTWARE USER MANUAL User Manual

Page 80

Planning Your Application

Chapter 4

4-5

A block transfer address can be assigned to any PanelView terminal object,
window or PLC controlled option. PanelView references these addresses
according to block transfer file number (1–5), whether it’s a read or write
file, and its word (0–31) and bit number (0–15). The associated block
transfer instruction in the PLC controller will determine the actual PLC
address location of the read or write file. Each read or write file can
contain up to 32 PLC words.

Rack size and block transfer requirements depend on the number of
PanelView objects, windows and PLC controlled options that must interact
with the PLC controller. The smallest size is 1/4 rack. If you require more
objects or functions than can be supported by 1/4 rack, you can:

increase the rack size (to 1/2, 3/4, or FULL)

assign additional rack numbers

assign block transfers

First, determine what rack numbers you have available. Next, try to
estimate how many racks you will need and whether or not you’ll need
block transfers.

There may be certain objects, such as push buttons, that you will definitely
prefer to keep in discrete I/O. Discrete I/O provides faster updates than
block transfers. Similarly, you may have identified a certain category of
objects or functions that you plan on grouping together using block transfer
addresses.

Following is the number of discrete I/O image table words and bits
available for PLC communication with each of up to 8 rack numbers
assigned:

Table 4.C

I/O Image Table Words and Bits

Rack Size

16ĆBit Input

Words

16ĆBit output

Words

Total Input Bits

Total Output

Bits

БББББ

1/4

БББББ

1/2

БББББ

3/4

БББББ

FULL

БББББ

128

БББББ

128

Determining Rack and Block

Transfer Needs