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scheduled time. The I/O module receives and stores the schedule. The CIP Sync
time of each schedule is monitored by the module. When a schedule has
expired, that is the current time, matches the scheduled timestamp, the output
value is then applied to the corresponding output bit. Timer hardware in the
ASIC is used to optimize the scheduling algorithm. This hardware also reduces
the latency and jitter performance. Status of each schedule is reported in the
output echo connection and reflected in the input image for the module.
The scheduled output functionality relies on CIP Sync time. Unused outputs
may be used as normal outputs and are applied immediately rather than
waiting for the CIP Sync time to expire. A mask is sent to the module to
indicate which outputs are to function as normal outputs. The scheduled
output module supports up to 8 outputs that can be individually scheduled.
The scheduled outputs must be between output points 0 and 7. The 1732E-
OB8M8SR module supports up to 16 schedules with two schedules per output.
Outputs that are not "scheduled" are used as normal output points. A mask is
used to indicate which points are scheduled and which points are
unscheduled. Jitter performance is less than 25 μs. All of the scheduling
configuration is done through the MAOC instruction.
If a new schedule as indicated by a change in the sequence count is received by
the I/O module before the current schedule has expired, the current schedule is
overwritten. This mechanism can be used to cancel currently active schedule.
Status bits returned in the output echo connection may be used to determine
the current state of each schedule and to trigger corresponding event tasks.
If a new schedule is sent by the controller and the CIP Sync time has already
past, the output is asserted until the CIP Sync time has completely wrapped
around. The module does not check for an expired CIP Sync time.
WARNING: If the time between two schedules is less than the minimum schedule
interval (for example, 100 µs), then deviation occurs. This means that even though
two outputs are scheduled at different times (for example, time 90 and time 110),
they both activate at the same time (for example, time 90). The minimum schedule
interval should not be set to faster than 100 µs.
High Speed Product Reject
In a control system you can program a scheduled output module, which can
trigger multiple outputs simultaneously or trigger a reject at the precise point
a product is at the reject station.
By using time to schedule the output in advance, and identifying when the
product will be at a known position, hitting the exact point when a part is in
front of a reject station on a high speed packaging machine, can be controlled.
Rockwell Automation Publication 1732E-UM003D-EN-E - November 2021
Chapter 2
Module Overview and Features
17
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