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SMD17E2 User Manual
SMD17E2 SPECIFICATIONS
13
The SMD17E2 Family (continued)
General Functionality (continued)
The SMD17E2 units have two DC inputs that are used by the indexer. Configuration data from the host sets
the function of these inputs. Each input can be individually configured as a:
CW or CCW Limit Switch
Home Limit Switch
Capture Position Input (Will capture encoder position on units with the internal encoder.)
Stop Jog or Registration Move Input
Start Indexer Move
Emergency Stop Input
General Purpose Input
Encoder Functionality
All SMD17E2 units can be ordered with an internal incremental or absolute multi-turn encoder. Incremental
encoders can be programmed to 1,024, 2,048, or 4,069 counts per turn. Absolute encoders have a fixed reso
-
lution of 2,048 counts per turn and encode a total of 2
21
turns. (32 bits total.) Using an encoder gives you the
ability to:
Verify position during or after a move
Detect motor stall conditions
Maintain machine position when power is removed if using an absolute encoder.
Close the position/velocity loop with the encoder position instead of the motor position when following
a virtual axis.
The motor position can be preset to the encoder position with a single command. SMD17E2 units with abso-
lute encoders allow you to preset the encoder position and save the resulting offset in Flash memory.
Network Data Format
In order to support any host that communicates with the supported protocols, the format of the data read from
and written to the SMD17E2 while in command mode is completely programmable. The format of the network
input and output data can be programmed separately.
The smallest data size used by the SMD17E2 is the sixteen bit word, however some parameters and data values
can exceed this size. For these thirty-two bit values, the default data format is referred to as the
multi-word
for-
mat. The data value is split between the hundreds digit and the thousands digit. For example, a value of 12,345
would have 12 placed in the first (lower addressed) word, and 345 placed in the second (higher addressed)
word. This format greatly simplifies setting parameter values when programming command blocks.
The other data format is a signed thirty-two bit integer format. When using the thirty-two bit format, there is
one additional parameter named Data Endian. Its use is best explained with an example. The value of
123,456 equals 0001:E240 in hexadecimal. When storing and transmitting this data, some host controllers
will store the least significant word (16#E240) in the lower addressed word in their data tables, while others
will store the most significant word (16#0001) stored in the lower addressed word in their data tables. These
controllers expect thirty-two bit values to be returned to them using the same format. Least significant word
first is called little endian, most significant word first is called big endian. Rockwell Automation controllers
use little endian format, the default Modbus format is big endian, and the default PROFINET format is big
endian.
The range of values when using the multi-word format is -32,768,000 to 32,767,999. When
used in continuous rotation applications, it is possible to overflow these values. When a posi-
tion value overflows, the value of the associated data words will become indeterminate. AMCI
strongly suggests using the signed 32-bit integer format for continuous rotation applications.
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