Network Force/Torque Sensor System

Net F/T Installation and Operation Manual
Document: 9620-05-net ft-11
10. UDP Interface Using RDT
The Net F/T can output data at up to 7000 Hz over Ethernet using UDP. This method of fast data collection is
called Raw Data Transfer (RDT). If the overhead of DeviceNet or EtherNet/IP is too much for your project, or
you need extra speed in your data acquisition, RDT provides an easy method to get the forces, torques, and
status codes of the Net F/T system.
NOTICE: Multi-byte values must be transferred to the network high byte first and with the correct
number of bytes. Some compilers align structures to large field sizes, such as 32- or 64-bit fields,
and send an incorrect number of bytes. C compilers usually provide the functions htons(), htonl(),
ntohs(), and ntohl() that can automatically handle these issues.
10.1 RDT Protocol
There are six commands in the RDT protocol. These are listed in Table 10.1—RDT Commands. Any
command received by the Net F/T will take precedence over any previously-received commands.
Table 10.1—RDT Commands
Command Command Name Command Response
0x0000 Stop streaming none
0x0002
0x0003
0x0004
Start high-speed real-time
streaming
Start high-speed buffered
streaming
Start multi-unit streaming
(synchronized)
RDT record(s)
RDT record(s)
RDT record(s)
0x0041 Reset Threshold Latch none
0x0042 Set Software Bias none
The three streaming modes are further described in Table 10.2—Streaming Modes.
Table 10.2—Streaming Modes
Mode Command Speed Situation Best Suited To
0x0002
Start high-speed real-time
streaming
Fast (up to 7000 Hz)
Real-time response applications.
0x0003
Start high-speed buffered
streaming
Fast (up to 7000 Hz), but comes
in bursts (buffers)
Collecting data at high speed, but not
responding to it in real-time. Buffer size
is set on the Communication Settings
web page. See Section 4.8—
Communications Settings Page
(comm..htm).
0x0004
Start multi-unit streaming
(synchronized)
Slower, depending on the
number of sensor systems
involved
Multi-unit synchronization. The multi-unit
ID number is set on the Communication
Settings web page.
To start the Net F/T outputting RDT messages, you first send an RDT request to it. The Net F/T listens
for RDT requests on UDP port 49152. It also sends the RDT output messages from this port.
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