Rockwell Automation 1771-DB BASIC MODULE - Manual (Page 31)

Chapter
Installing the BASIC Module 1
1 -7
Set Backplane Configuration (JW5)
Use JW5 to set the BASIC module backplane configuration. The BASIC
module can perform both block and discrete transfers. With JW5 set to
8-point mode, the BASIC module uses 8 bits in both the input and output
image table for block transfer. When you have JW5 (page 1 -7)
configured for 16-point mode, the firmware also allows you to
examine/use bits 10–17 for status of the communication ports.
Important: When the BASIC module is in 16-point mode you must
perform all block-transfers synchronously with a PLC-5 processor.
Asynchronous block transfers do not work with this configuration and
cause the backplane circuit within the module to lock up. The BASIC
module ships with JW5 configured for 8-point mode (Series A
compatible). Unless you are using calls 32, 33, 34, 49, 50, 118, 122, or
123 (see Chapters 12 and 13) you should be in 8-point mode.
Important: You cannot use 2-slot chassis addressing if this jumper is set
for 16-point mode. See page 1 -10 for information regarding the backplane
configuration and addressing.
Input image bits Output image bits Read block words Write block words Jumper setting ✔ your selection:
8 8 64 max 64 max
factory setting
(Series A setting)
16 16 64 max 64 max ①
① 2-slot chassis addressing not allowed. Block transfers must be synchronous.
Refer to Chapter 5 for more information regarding the backplane mode.
Chapter