I/O Assembly Instances; Process Data - Danfoss VLT DeviceNet MCA 104 Programming Manual

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VLT DeviceNet MCA 104
The attribute expected package rate defines the maximum time between 2 COS messages even when the value is
unchanged. In the event of COS connection, the explicit package rate is identical with the heartbeat interval mentioned
above. This timer is used both as transmission trigger and inactivity watchdog, depending on whether the connection is
producer or consumer.

4.2 I/O Assembly Instances

I/O assembly instances are several defined process control objects with defined content comprising control and status
information. Illustration 4.2 shows the I/O assembly instance options for controlling and monitoring the frequency converter.
4 4
Illustration 4.2 I/O Assembly Instance Options

4.3 Process Data

Process data comprises the control and status data in the I/O assembly instances.
The CTW, MRV, STW, and MAV have defined formats and functions, depending on the I/O instance selected. PCD 3 and PCD
4 are freely configurable, for instance 101/151 via parameter 10-11 Process Data Config Write and parameter 10-12 Process
Data Config Read.
All PCDs are freely configurable for instance 102/152.
DeviceNet provides a flexible way to customize the number of process data (I/O words) and the functionality of each word.
To activate the user definable process data, select the I/O instance 101/151 in parameter 10-10 Process Data Type Selection.
This changes the I/O size to 4 words in the input and output area. This selection uses the Danfoss-specific profile for the
control word and status word as well as for the main reference value/main actual value.
The first 2 words are fixed on the DeviceNet, whereas PCD 3 and PCD 4 are user configurable. The number of PCDs active in
a system is fixed to 2 words.
NOTICE
To select [1] Instance 101/151 in parameter 10-10 Process Data Type Selection, set parameter 8-10 Control Word Profile to
[0] FC profile.
To enable use of PCD data from the DeviceNet, configure the contents of each single PCD word in parameter 10-11 Process
Data Config Write and parameter 10-12 Process Data Config Read. Changes to parameter 10-11 Process Data Config Write and
parameter 10-12 Process Data Config Read are effected immediately in the PCD data.
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