Assignment Of Inputs And Outputs To The Master Station In A Remote I/O System; I/O Assignment Restrictions - Mitsubishi MELSEC-A Series Reference Manual

7. DATA LINK SETTINGS

7.11 Assignment of Inputs and Outputs to the Master Station in a Remote I/O System

When a remote I/O system is configured with the MELSECNET data link system, there are
restrictions on the I/O assignment for the master station.
The following describes the I/O assignment of master station which consists of a remote
I/O station.
In case of the master station/local station which links to local stations only, I/O assignment
can be executed in the same manner as for an independent system.
REMARK
I/O addresses are automatically assigned by the programmable controller CPU.
A peripheral device is not particularly required for I/O assignment. However, I/O
assignment with a peripheral device enables followings.
• Saving I/O points (16 points) occupied by an empty slot.
• Reserving number of I/O points (32, 48, or 64 points) at an empty area for the

7.11.1 I/O assignment restrictions

(1) I/O assignment must be made from the head address (X/Y0) to the final address
assigned to the remote I/O station.
Failure to complete I/O assignment up to the final address will cause an error in the
master station.
The I/O range to be assigned differs depending on the order of the M/L area and the
M/R area set by the link parameters.
(a) If the M/L area is assigned after the M/R area, it is not necessary to assign inputs
(b) If the M/L area is assigned after the M/R area, it is necessary to assign inputs
REMARK
In the I/O assignment setting, the device range is set with the assumption that the
input modules or output modules are installed in the area of "M/L area" or that empty
slots exist in the "empty area (range marked by *)" Fig 7.48.
system expansion in the future.
and outputs to the local station setting range. (Refer to Fig 7.48 (a).)
and outputs to the local station setting range. (Refer to Fig 7.48 (b).)
Fig 7.48 I/O assignment setting range
MELSECNET mode MELSECNET
MELSECNET MELSECNET
Operating Mode
mode
mode
Applicability
7 - 81
MELSECNET/B
MELSECNET MELSECNET MELSECNET MELSECNET
composite mode mode composite mode
mode