Centro de Competencia Técnica (CCT)

Advantys STB Virtual Module

Summary
Because reflex actions are designed to operate independently from the fieldbus master, inputs to the reflex blocks generally come from local input modules. In some applications, however, you may want the fieldbus master to provide an input value to a block. You can realize this using the virtual module.
The Advantys Configuration Software provides 3 words in the output process image where the fieldbus master may write digital and/or analog values for use exclusively as inputs to the reflex actions. These 3 words comprise the virtual module.
Virtual Module Structure
If you choose to use the virtual module, it may be 1, 2 or 3 words in length:
If you want to use the virtual module ... / Then the virtual module will be ...
only for digital inputs / 1 word long. It provides 16 bits where the fieldbus master can write up to 16 digital inputs to the reflex actions.
only for analog inputs / 2 words long. It will provide 2 words where the fieldbus master can write up to 2 analog input values to the reflex actions.
for both digital and analog inputs / 3 words long. The first word provides 16 bits for digital inputs and the second and third words are for 2 analog input values to the reflex actions.
Note: If you look at the virtual module data in the Modbus Image tab of the I/O Image Overview window, the 16 bits of digital virtual data will be displayed in the low bytes of 2 separate registers. If you look at the virtual module data in the Fieldbus Image tab, the 16 bits of digital virtual data may be displayed either in a single 16-bit word or in the low bytes of 2 contiguous words, depending on the fieldbus. The STBNMP2212 Modbus Plus NIM and the STBNIP2212 Ethernet NIM display virtual digital data the way they are displayed in the Modbus Image.
The word or words used for the virtual module are always the last words in the output process image. If all 3 words are used, the digital word will appear first followed by the 2 analog words.
Selecting the Virtual Module
The size of the virtual module in your process image is determined by your selection of inputs to the reflex actions in your Island configuration.
For example, suppose you are setting up a falling-edge analog latch. The latch has 3 inputs: an enable input, a latch trigger and an analog operational input. The enable input and the trigger need to be boolean (digital) inputs, and the operational input needs to be an analog word.
When you are selecting the source for the enable and the trigger inputs, 1 of the choices that will appear in both input list boxes is Virtual Module (D):

If you select an input called Virtual Module (D), the virtual-module word for digital inputs becomes part of the output process image. This means that the fieldbus master needs to write to 1 of the virtual module’s 16 available bits to control the enable input and/or the trigger input.
Suppose you are configuring the operational input to that falling-edge analog latch. The operational input must be an analog integer value. When you go to the list box to specify the source of the operational input, 1 of your choices will be Virtual Module (D):

If you select Virtual Module (A) as the input, the 2 virtual-module words for analog inputs become part of the output process image. The fieldbus master needs to write an operational input to the first word in the analog latch block

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