Schneider Electric 890USE17700 manual Nesting

	Advanced Configuration Features
Nesting	The Advantys configuration software allows you to create nested reflex actions. One
	level of nesting is supported—i.e., two reflex blocks, where the result of the first
	block is an operational input to the second block.
	When you nest a pair of blocks, you need to map the results of both to the same
	action module. Choose the action module type that is appropriate for the result of
	the second block. This may mean that in some cases you will need to choose an
	action module for the first result that does not seem to be appropriate according to
	the table above.
	For example, say you want to combine a counter block and a compare block in a
	nested reflex action. You want the result of the counter to be the operational input to
	the compare block. The compare block will then produce a Boolean as its result:

first nested action

enable falling-edge counter

operational input

counter preset

counter direction

reset

result 1

action module: STB DDO 3410 channel: none

second nested action

enable

operational input (result 1)

less than threshold compare threshold +/- ∆

result 2

action module: STB DDO 3410 channel: 4

Result 2 (from the compare block) is the result that the nested reflex action will send to an actual output. Because the result of a compare block needs to be mapped to a digital action module, result 2 is mapped to channel 4 on an STB DDO 3410 digital output module.

Result 1 is used only inside the module—it provides the 16-bit operational input to the compare block. It is mapped to the same STB DDO 3410 digital output module that is the action module for the compare block.

Instead of specifying a physical channel on the action module for result 1, the channel is set to none. In effect, you are sending result 1 to an internal reflex buffer where it is stored temporarily until it is used as the operational input to the second block. You are not really sending an analog value to a digital output channel.

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