Omron CJ1W-MA - REV 10-2008, Operation Manual

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MECHATROLINK Settings Section 6-2
Communications
Cycle
The communications cycle is the cycle used to refresh data in the PCU and
MECHATROLINK devices. The PCU sends operating commands to the con-
nected MECHATROLINK devices and refreshes present positions, status, and
other monitoring information every communications cycle.
The set value for the PCU's communications cycle is an integer used as a
multiplier to obtain integer multiples of the transfer cycle. The actual communi-
cations cycle (data refresh cycle) is a time cycle that is a multiple of the trans-
fer cycle's set value. The set value for the communications cycle is
determined by the number of connected MECHATROLINK devices and
depends on the PCU communications processing.
The actual communications cycle (data refresh cycle) is a time cycle calcu-
lated by multiplying the transfer cycle by a set value. The lower limit of the
communications cycle is determined by the number of connected MECHA-
TROLINK devices and depends on the PCU communications processing.
When the default setting of 0 is used, the communications cycle is three times
the length of the transfer cycle. Set the communications cycle so that the max-
imum value does not exceed 32 ms. When connecting a G-series Servo
Drive, set the communications cycle so that the maximum value does not
exceed 16 ms.
The following diagram illustrates data exchange with the PCU.
Number of Communications Retries
The number of communications retries is the number of stations that will per-
form retries if data sending/receiving fails when transferring data that is
exchanged between the PCU and MECHATROLINK devices using the trans-
fer cycle. The set value is set as the maximum number of stations used to
retry data transmission with the slave station for which data sending/receiving
failed.
The number of communications retries can be set between 0 and 7 (commu-
nications retries for up to 7 stations). The set value for the number of retries,
however, is added to the number of connected stations that determine the
transfer cycle (e.g., for 3 retries, the transfer cycle must be considered as that
for the number of stations connected plus 3). For normal use, use the default
setting of 0 (1 communications retry).
C2 Master Connection
The C2 master is a separate communications master connected to the PCU
for MECHATROLINK system support. This setting will be used when a future
system support device is connected. Use the default setting 0 (No C2 master).
MECHATROLINK
CPU Unit PCU Servo Drive
Ladder processing PCU processing Servo processing
Cycle time
(end refresh) Communications cycle
(data refresh cycle in PCU) Transfer cycle (data
transfer cycle in
MECHATROLINK) Servo Drive's data
refresh cycle (by Servo
Drive)