Panasonic MEWNET-F, Technical Manual

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3-10
3.5 Communication Time
The communication time regarding the remote I/O system [MEWNET-F] control is described.
3.5.1 Remote I/O Scan Time [T
R
]
The remote I/O scan time represents the time it takes the master unit, with respect to the connected
slave stations, to send all the output data which has been written to the buffer memory in the master unit
and write all the input data received from the slave stations to the buffer memory in the master unit.
T
R
=0.8+0.85×n+0.55×N+0.13×W (ms)
n
: No. of I/O terminal boards
N : No. of slave units
W : No. of I/O words used by the remote I/O system
[Example]
When 10 FP I/O terminal boards (16 input points and 16 output points) and a salve station (connected to
one slave unit, 4 input units (32 input point), 4 output unit (32 output points)] are connected.
3.5.2 Remote I/O Memory Access Time [T
RM
]
The remote I/O memory access time represents the time it takes the master unit to receive the memory
access end message from the slave unit after it receives a memroy access request from the CPU.
As this value is a guide, confirm on the actual units.
[Example]
When 5 I/O terminal boards (16 input points and 16 output points each) and a slave station [connected
to 1 slave unit, 2 input units (32 input points), 2 output unit (32 output points) and 1 advanced unit
(occupies 32 points)] are connected and a 32-word memory access is performed with an advanced unit.