6RL SERIES OPERATION MANUAL
SECTION 7: REMOTE PROGRAMMING
Entire Contents Copyright
2018 by Adaptive Power Systems, Inc. (APS) • All Rights Reserved • No reproduction without written authorization from APS.
6RL Series Regenerative DC Load Operation Manual
Page 178 of 204
7.14
CANopen
For CANopen available communication objects or registers, indexes are defined in an Electronic Data
Sheet file (EDS/XDD), which is delivered with your unit on a CD or available upon request. This EDS
can be integrated in special CANopen related software. The CANopen indexes are not separately
explained, because their definition and use is identical to herein described ModBus protocol and the
related, external register list files.
The difference is only that the ModBus register addresses count up from 0 and with CANopen,
according to the standard and the interface specification of the manufacturer, the user indexes are
located from 0x2001. It means, the register addresses as listed in decimal form in those register list
are shifted by the value 0x2001 (8193). Examples from the ModBus part of this document can be
used and applied for CANopen as well, but reduced to the core data, because CANopen is not
confronted with checksums and function codes as is ModBus.
Note:
The CANopen module IF-AB-CANO does not feature an internal termination resistor. Thus
the required bus termination resistor has to be applied by the user according to the CAN bus
requirements.
7.14.1
Preparation
For the communication with the unit via CANopen interface IF-AB-CANO, a few things are required:
1.
A suitable CAN cable, preferably with switchable termination resistor, which has to be
activated, always if the unit is at the end of the bus, like when directly connecting the PC to a
single ELR 9000 unit.
2.
EDS/XDD (usually provided along with this document).
3.
CANopen software for the PC (not included, any available software for CANopen should
suffice).
4.
Documentation about how to use the supported indexes. See the included register list(s).
7.14.2
User objects (indexes)
The message format used via CANopen communication is related to ModBus. A specific index is
connected to a specific ModBus register. The CANopen standard defines that user objects are
enumerated from index 2001. With ModBus, the registers are counted from 0. It means, that index
2001 corresponds to register 0 or index 21F5 corresponds to register 500 etc.
The EDS/XDD contains less indexes than the unit supports ModBus registers. But the available
indexes still cover the most functions of the unit to be used via remote control.
Along with this document there usually are so-called register lists for primary ModBus use, but these
can also be used for CANopen, as they also define data type and value range of the indexes. Examples
in other sections of this documents can be applied for CANopen as well.
7.14.3
Translation ADI -> register
The translation of an CANopen index, as listed in the EDS file, to a register address is quite easy due
to the fixed offset 0x2001. For example, if you pick the index “207A Nominal voltage” from the EDS, it
translates like this:
Index number - Offset = register address --> 0x207A - 0x2001 = 0x79 (hex) = 121 (dec). Because
CANopen does not support the data type FLOAT, the EDS uses REAL32 here. The user just has to
translate the 32-bit value according to IEEE 754 specification.
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