Manual, FT Sensor, Ethernet Axia
Document #9610-05-Ethernet Axia-05
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9.2 Calculating F/T Values for RDT
To obtain the real force and torque values, each force output value has to be divided by the Counts per Force
and each torque output value has to be divided by the Counts per Torque factor. The Counts per Force and
Counts per Torque factors can be obtained from netftapi2.xml page. See cfgcpf and cfgcpt in
System and Configuration Information (netftapi2.xml)
9.3 Multiple Clients
The RDT protocol is designed to respond to one client only. If a second client sends a command, the
Ethernet Axia responds to the new client. Multiple clients could repeatedly request single packets,
minimizing problems. (The Java demo operates in this manner.)
9.4 Notes on UDP and RDT Mode
RDT communications use UDP, with its minimal overhead, to maximize throughput. UDP does not check if
a package was received.
In some Ethernet network configurations, this can lead to the loss of RDT data sets. By checking the RDT
sequence number of each set, it can be determined if a data set was lost. The RDT sequence number of
each data set sent will be one greater than the last data set sent for that RDT request. If a received data set’s
RDT sequence number is not one greater than the last received data set, then a loss of data has occurred (the
program must also account for rollover of the RDT sequence number).
The likelihood of data loss highly depends on the Ethernet network configuration and there are ways to
reduce the probability of data loss to almost zero. Refer to
Section 12.8—Improving Ethernet Throughput
for
details.
The maximum data latency, measured from the beginning of data acquisition to when the last data bit is sent
to the Ethernet network, is less than 28 ms.
The Ethernet Axia only supports one UDP connection at a time.
9.5 Example Code
Example C code can be found on the ATI website at
http://www.ati-ia.com/Products/ft/software/net_ft_
and on the file that was sent via e-mail to the customer, when the product was shipped.