ICP DAS USA DB25 - Manual (Page 37)

DeviceNet to Motor Drives
31
The DN-3000 supports up to a total of 64 bytes (32 words) of combined Input and Output data. Each
word (2 bytes) of Input or Output data can be configured to exchange data with any one valid parameter
in any one of the motor drives connected to port 2 of the DN-3000 (see “CONFIGURING PORT 2” for
motor drive type and communication parameters).
Use Command Block
In some projects it may be necessary to be able to access more than just the 32 motor drive parameters
that can be configured in the Input and Output data. A Command Block reserves the first 3 words of
Output data for commands, and the first 3 words of Input data for command results. This reduces your
total number of words that can be used for parameter data to 26 words, but adds flexibility by allowing
your DeviceNet Host to issue commands to the DN-3000 to access any valid parameter in any motor drive
connected to port 2 of the DN-3000. Commands are issued by moving a command code, motor drive
address, parameter number, and data into the first 3 words of the Output data (see “COMMAND
BLOCK”).
Use Diagnostics
Diagnostics allows the DeviceNet Host to monitor motor drive connections to the DN-3000. The first
word of the Input data following the Command Result Block (if any) will be reserved for Diagnostics if
this option is selected. The DN-3000 keeps track of the connection status with each motor drive address
(0-255). Whenever an attempt to communicate with a motor drive address is successful, the connection
status for that address is set to ‘0’. Whenever an attempt to communicate with a motor drive address is
unsuccessful, the connection status for that address is set to ‘1’. Of course, returning 256 status bits
would require 16 words of Input data (half of the available I/O data). Instead, only 16 bits (1 word) of are
returned. Each of the 16 bits of the Diagnostics word represents the status of 16 motor drive addresses, as
follows: bit 0 represents motor drive addresses 0, 16, 32, 48, 64, etc.; bit 1 represents motor drive
addresses 1, 17, 33, 49, 65, etc.; and so forth. If the status of any of the motor drive addresses represented
by a bit is ‘1’, that bit will contain a ‘1’, otherwise, that bit will contain a ‘0’. Note that the status of a
motor drive address is set to ‘1’ only if the DN-3000 attempts to communicate with that motor drive
address and that attempt is unsuccessful.
Output Data Size
This determines the number of words of Output data that will be used in your project. Output data is data
that is output from your DeviceNet Host to the DN-3000 (commands, and parameter data to be written to
motor drives). This is also known as the Consumed I/O Data of the DN-3000. If a Command Block is
used, it will automatically reserve 3 words of Output data. The combined size of the Input and Output
data must not exceed 32 words.
Output Data
Pressing the Output Data button brings up a window allowing you to edit the configuration of the Output
data in your project. You can press the Output Data button by clicking on it with your mouse, or moving
the focus to the button with the arrow keys and pressing the SPACEBAR. See “OUTPUT DATA
TABLE CONFIGURATION”.