IMO i3N Series, Руководство пользователя

Страница: 72 / 94

72
12.6 Data Mapping Configuration (Scan List Entry)
Update Type
This field specifies the direction and what triggers the transfer of data between the i3 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 i3 is placed in RUN mode, the initial action for this mapping type is a read target register
transaction.
This transaction initializes the local (i3) register(s) to match that of the remote device
register(s). Thereafter, any change to the corresponding i3 register(s) triggers a write operation to the
remote device.