MAN0974-14-EN_XL7_XL7P_UM
July 6, 2022
Page 130 | 199
13.6 Data Mapping Configuration (Scan List Entry)
Update Type
This field specifies the direction and what triggers the transfer of data between the OCS and target
device for a mapping entry.
Polled Read
On every transaction scan, a read-only target device register(s) transaction occurs.
Polled Read/Write
On every transaction scan, a read target device register transaction occurs unless a local register value
has changed. The write transaction only updates those local registers that have changed in value. If
several non-consecutive local registers (contained in a single mapping entry) change value between
transaction scans, it takes several consecutive transaction scans to write each changed register.
When the OCS is placed in RUN mode,
the initial action for this mapping type is a read target register
transaction.
This transaction initializes the local (OCS) register(s) to match that of the remote device
register(s). Thereafter, any change to the corresponding OCS register(s) triggers a write operation to the
remote device.
