ElmoMC CANopen DS 301 Implementation Guide - Manual (Page 11)

2.4 Inhibit Times
The inhibit time for a given message type is the minimum time that must elapse from the
time the message is first transmitted until the time that it may be transmitted again. The
purpose of inhibit times is to ensure that high-priority messages do not flood the bus
and thereby prevent service messages of lower priority from being transmitted. The
inhibit times of
SimplIQ drives are defined only for asynchronous transmit process data
objects (TPDOs), by sub-index 3 of the associated transmission type object. The resolution
of the inhibit time is 100 microseconds, with an accuracy of 2 milliseconds.
Note: If several events occur during the inhibit time of a message, only the last
message will be transmitted when the inhibit time extinct. For example, if TPDO3 is
activated by digital input 1 and digital input 3 with an inhibit time of 10
milliseconds, then if a digital input 1 event emits TPDO3 at time 0, a digital input 3
event occurring 5 milliseconds later will not cause any TPDO3 transmission for the
next 5 millisecond. The TPDO3 transmission would be postponed, allowing other
messages to be transmitted, until the inhibit time is exhausted.
The DS 301 version 4.0 protocol allows the user to modify the inhibit time only for COBs
that are not valid (sub-index 1 of objects 0x1400 and 0x1800), while
SimplIQ drives allow
the user to modify the inhibit time at any time, with pending messages being discarded
according to that time definition.
2.5 RTR – Remote Transmission Request
The RTR is not supported by the Elmo drive.
2.6 Object Dictionary
An object dictionary (OD) is a naming system that gives a unique identifier to each data
item — or “object” —that is communicated over the CAN bus. An object is identified by
an index and, if it is a complex object, also by a sub-index. A CANopen client can
manipulate an object of a CANopen server by referring to its identifier, according to the
access permission of the object. (An object’s access permission may be read-only, write-
only, or read-write.)
CiA DS 301 requires a set of mandatory objects for all CANopen devices. Other OD items
are predefined by CiA DS 301 to have fixed identifiers, if supported. The OD also
accommodates manufacturer-specific objects.
CANopen DS 301 Implementation Guide CANopen Basics
MAN-CAN301IG (Ver. 2.1)
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