8I20 16
CONTROLLERS
MULTI-AXIS CONTROLLERS
Two basic types of multi-axis controllers are available for use with the 8I20, host
based and "Smart". Host based controllers use the host computer to read encoders and
output angle and run a PID loop that outputs torque commands to the 8I20. The HostMot2
FPGA firmware suite is a host based motion controller that is compatible with the 8I20.
Smart controllers like SoftDMC take higher level motion commands from the host and
control all low level processes like reading encoders, running the PID loop and flagging
error conditions.
HOSTMOT2 8I20 INTERFACE
The Hostmot2 interface to the 8I20 is a smart serial interface for Mesa’s Anything
I/O series of FPGA cards that encapsulates the serial protocol details and presents a
simple parallel register set to the host computer. Registers for writing torque and angle and
registers for reading bus voltage, card status, communication status, and card temperature
are provided for all connected 8I20 cards.
The 8I20 Hostmot2 interface is a sserial module with specific firmware (SSLBP) for
8I20 card or other LBP interfaced cards. Each sserial module can support up to eight 8I20
cards. The sserial module supports the standard 2.5 M Baud communication rate and
torque update rates to 5KHz. With the default configuration, the Hostmot2 interface sends
reference angle (ANGLE parameter) and current (QSETPOINT parameter) commands and
receives bus voltage (BUSV parameter), 8I20 card temperature (TEMPERATURE
parameter), and 8I20 status and fault information (STATUS and FAULT parametera).
A complete host based controller will also need position sensing. This may consist
of quadrature encoders, SSI absolute encoders (including magnetic absolute types), or
resolvers. All three types of position sensors are available in the Hostmot2 firmware suite.
SOFTDMC 8I20 INTERFACE
SoftDMC is a smart multi-axis motion controller with built in motion profile generator,
programmable exception handling and a high performance FIFO based host interface.
SoftDMC is a firmware option for Mesa’s Anything I/O series of FPGA cards. For more
information on SoftDMC, please consult the SoftDMC manual.
ANYTHING I/O INTERFACE DAUGHTER CARDS
8I20 compatible daughter cards are available to simplify connecting the 8I20 to
Mesa’s Anything I/O FPGA cards. One interface card is the 7I44. The 7I44 provides 8
channels of RS-422/RS-485 serial communication interface. The 7I44 uses RJ-45
connectors for the serial interface. These connectors are compatible with the 8I20 so a
common CAT5 or CAT5E cable may be used to connect from the 7I44 to the 8I20. The
7I44 can also provide 5V power to the 8I20 subject to the CAT5/5E cable length
restrictions.
