Parker
Hannifin
velocity are at P38160 and P38161 respectively. Similarly, EPLD position is
the actual EPLD position, updated every servo period, and EPLD velocity is
the change in EPLD position each servo period.
In addition to their use in the
ATTACH
and
OPEN
commands described later,
EPLD objects may be used as SRC (source) objects anywhere that ENC
may be used, such as cams and gears. It is also possible to reset or offset
the EPLD position using
EPLDn RES
. But an EPLD is more like an absolute
encoder than an incremental encoder, because the count value is received
by the ACR9030 and ACR9040 as an absolute value, not incrementally. For
this reason, the
EPLDn RES
value will simply be added as an offset to the
absolute raw value provided by the drive, just as is done with an absolute
encoder.
ATTACH AXIS EPLD Command
The
ATTACH AXIS EPLD
command is a new AcroBASIC command needed
for use with EPL drives. This command is used in the same way as, but in
place of, the
ATTACH AXIS ENC DAC
command. In other words, an EPLD
object takes the place of both an encoder and a DAC. When EPLD is the first
token following
ATTACH AXIS
, no other tokens are accepted. When this
command is executed, the controller knows to use the EPL network as
described above instead of closing the position loop on that axis.
Just as any AXIS can be attached to any ENC or DAC, any AXIS can be
attached to any EPLD. For example, suppose a 2 axis ACR9030 also has an
EPL card and three EPL drives. The following commands would be valid.
ATTACH AXIS0 ENC0 DAC0
ATTACH AXIS1 ENC1 DAC1
ATTACH AXIS2 EPLD0
ATTACH AXIS3 EPLD1
ATTACH AXIS4 EPLD2
See the ACR Command Language Reference for information on other EPL
commands (
DIAG EPLD
,
OPEN EPLD
,
EPLC
,
EPLC OFF
,
EPLC ON
).
Access to EPL Drives’ Native Command Language
It may be necessary to communicate with an EPL drive in its native language
in order to fully set up the drive, or take advantage of features not covered by
ACR9030 or ACR9040 functions. The Aries EPL has a TCP server that
listens on Port 5002 for connections to its native command language parser.
The ACR9030 and ACR9040 provide a way of communicating with EPL
drives using their own command language, while the drives remain
connected to the EPL network. This capability can also be accessed easily
via the terminal emulator in ACR-View.
Basic Ethernet Connections
Part of the EPL specification requires that an EPL device be able operate in
“basic Ethernet” mode (as a standard Ethernet device). This means that the
Aries EPL drive, for example, will accept commands over TCP/IP
connections. When a drive is not part of an EPL network, its Ethernet
connection is strictly devoted to TCP/IP.
Appendix H ETHERNET Powerlink 179
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Summary of Contents for ACR9000
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