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67
REFERENCE 6
C
OMMAND
M
ODE
D
ATA
F
ORMAT
Data Format
An SMD23E2 or SMD24E2 requires twenty bytes of Output Data as well as twenty bytes of Input Data. In
most cases the data is represented as ten 16-bit (single) integers. Sixteen bit integers support a range of values
from -32,768 to 32,767 or 0 to 65,535. When issuing commands to the SMD23E2 or SMD24E2, there are
several parameters that are larger than sixteen bits. These parameters are:
Target Position
Programmed Speed
Stopping Distance
Minimum Registration Move Distance
Position Preset Value
Encoder Preset Value
Likewise, when reading data back from a unit while it is in Command Mode, there are values that are larger
than sixteen bits. These data values are:
Motor Position
Encoder Position
Captured Encoder Position
By default, these thirty-two bit parameters and data values are written to and read from the SMD23E2 and
SMD24E2 using the multi-word format described below. When configuring the SMD23E2 or SMD24E2, it is
possible to program it to use a 32-bit double integer format instead of the custom format shown above.
There are three configuration bits that control the data format when the SMD23E2 or SMD24E2 is in com-
mand mode. The
Binary_Output_Format
Bit, controls the format of the programmable parameters written to
the SMD23E2 or SMD24E2 when issuing commands. The
Binary_Input_Format
bit controls the format of
the data values written to the host controller by the SMD23E2 or SMD24E2. When either of these parameters
are set to their 32-bit signed integer format settings, the
Binary_Endian
bit determines if the 32-bit values are
stored and transmitted least significant bits first or most significant bits first. Examples of the formats are
given below.
Table R6.1 Position Data Format Examples
The range of values when using the multi-word format is -32,768,000 to 32,767,999. When
used in continuous rotation applications, such as control of a conveyor belt, it is possible to
overflow these values. When any of the three position values overflow, the value of the associ-
ated data words will become indeterminate. AMCI strongly suggests using the signed 32-bit
integer format for continuous rotation applications.
This chapter covers the formats of the Network Output Data used to command the
SMD23E2 or SMD24E2 and the formats of the Network Input Data that contains the
responses from the device. The SMD23E2 and SMD24E2 units require twenty
bytes of Output Data as well as twenty bytes for Input Data.
Multi-Word Format
32 bit Signed Integer
Little Endian Format
32 bit Signed Integer
Big Endian Format
Value
First Word
Second Word
First Word
Second Word
First Word
Second Word
12
0
12
16#000C
16#0000
16#0000
16#000C
-12
0
-12
16#FFF4
16#FFFF
16#FFFF
16#FFF4
1,234,567
1,234
567
16#D687
16#0012
16#0012
16#D687
-7,654,321
-7,654
-321
16#344F
16#FF8B
16#FF8B
16#344F
