Instruction manual

Introduction

890USE18300 September 2003

Nesting Two Reflex Blocks

Summary The Advantys configuration software allows you to create one level of nesting for

reflex actions. You can nest two reflex blocks, where the output from the first block

is used as an operational input to the second block. Both reflex blocks must be

nested within the same action module.

The Action

Module

In a nested reflex action, the output from the first reflex block is used internally—as

an operational input to the second reflex block. The output from the second reflex

block is used to update the physical output channel of the action module.

When you nest a pair of reflex blocks, you need to map the outputs from both to the

same action module. Choose the action module type that is appropriate for the

output from the second nested action block. In some cases, this means that you may

need to choose an action module for the first block that does not seem to be

appropriate for its output.

For example, say you want to nest counter-compare action. To do this, you need to

configure two action blocks with the reflex editor. The first block is the counter action

(See Counter Reflex Blocks, p. 93), and the second block is an unsigned compare

action (See Unsigned Compare Reflex Blocks, p. 71).

The output from a counter is always a 16-bit word value, and the output from the

unsigned compare is always a binary (Boolean) value. Intuitively, you might assume

that because the counter produces a word as its output it should be mapped to an

analog action module. However, since the counter is the first block in the nested

action and since the output from the second action—the unsigned compare—is a

Boolean, you need to select a digital output module as the action module.

The Physical

Outputs

The reflex editor requires that you specify the physical and logical output of each

reflex block that you configure. Generally, the physical output is the channel on the

action module to which the output of the action will be written. The physical output

is always mapped this way when an action is not part of a nesting; it is also how the

output from the second action block in a nested action is mapped. For the first block

in a nested action, however, the physical output is sent to a temporary memory

buffer. Instead of specifying an output channel on the action module, you need to

specify the physical output as None.