3DM
®
-GX5-35
DCP Manual
2.3.1
Example Data Packet:
Below is an example of a MIP data packet which has one field that contains the scaled
accelerometer vector.
Header
Packet Payload
Checksum
SYNC1
“u
SYNC2
“e”
Descriptor
Set byte
Payload
Length byte
Field Byte
Length
Field
Descriptor
Byte
Field Data:
Accel vector (12 bytes,
3 float – X, Y, Z)
MSB
LSB
0x75
0x65
0x80
0x0E
0x0E
0x04
0x3E 7A 63 A0
0xBB 8E 3B 29
0x7F E5 BF 7F
0x84
0xEE
Copy-Paste version: "7565 800E 0E04 3E7A 63A0 BB8E 3B29 7FE5 BF7F 84EE”
The packet header has the “ue” starting sync bytes characteristic of all MIP packets. The descriptor
set byte (0x80) identifies the payload field as being from the IMU data set. The length of the packet
payload portion is 14 bytes (0x0E). The payload portion of the packet starts with the length of the
field. "E The field descriptor byte (0x04) identifies the field data as the scaled accelerometer vector
from the IMU data descriptor set. The field data itself is three single precision floating point values of
4 bytes each (total of 12 bytes) representing the X, Y, and Z axis values of the vector. The checksum
is a two byte
(see the
for instructions on how to compute
a Fletcher two byte checksum).
The format of the field data is fully and unambiguously specified by the descriptor. In this example,
the field descriptor (0x04) specifies that the field data holds an array of three single precision IEEE-
754 floating point numbers in big-endian byte order and that the values represent units of “g’s” and
the order of the values is X, Y, Z vector order. Any other specification would require a different
descriptor (see the
section of this manual).
Data polling commands generate two individual reply packets: An ACK/NACK packet and a data
packet. Enable/Disable continuous data commands generate an ACK/NACK packet followed by
the continuous stream of data packets.
2.4
Example Setup Sequence
Setup involves a series of command/reply pairs. The example below demonstrates actual setup
sequences that you can send directly to the 3DM-GX5-35 either programmatically or by using a COM
utility. In most cases only minor alterations will be needed to adapt these examples for your application.
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