At the bottom of the Event Flow panel, you can click the Block Wiring tab to replace the Event Flow and Rules panels with the Block Wiring tab. The purpose of the Block Wiring tab is to allow you to interactively define how your scenario’s block instances are to be wired together.

Up to this point only block parameter wiring has been discussed. Recall that a block has parameters, input feeds, output feeds and operations. Parameters are intended for initializing the block, although they can then individually be updated during the block’s lifetime to modify its operation. Input feeds, on the other hand, are normally used when a block’s primary role is to process or transform some regularly changing data.

For example, the Change Notifier block’s purpose is to generate a notification when the value of a numeric input data stream changes by a given amount over a configurable moving time window. Its parameters define the time window and the amount that the monitored values must change by to trigger the notification, while the actual values being monitored would of course be an input feed.

A block might accept input data while not having an input feed. This is normally because the block’s author expects their block to be used alongside, and get all its input data from, dedicated EPL such as that included with external adapters. Good examples of this are the Market Data Management and the Order Management blocks such as Market Depth.

In general, a block is written to have exposed input feeds if its inputs can be provided by other blocks.

If you open a scenario and a block that was previously added to that scenario is missing you receive a pop-up error message, Event Modeler removes the block from the block wiring display, and there is an entry indicating the missing block in the Problems view.