Mitsubishi Digital Electronics FX Manual

A SERVICE OF

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Assigning System Devices 9

9-1

9. Assigning System Devices

9.1 Addressing Extension Modules

Most of the FX famil

y

of PLC’s have the abilit

y

to connect additional discreet I/O and/or special

function modules. To benefit from these additional units the user must address each block

independentl

y

.

Addressing Additional Discrete I/O

This t

y

pe of I/O is the standard

input and output modules. As each

extension block or powered

extension unit is added to the

s

y

stem the

y

assume the next

available ad-dresses. Hence, the

units closest to the base unit will

have the lowest I/O numbers or

addresses. I/O numbers are

alwa

y

s counted in octal. This

means from 0 to 7 and 10 to 17

etc. Within a users pro

g

ram the

additional addresses are used as

normal. Discreet I/O can be added

at the users discretion as lon

g

as

the rules of s

y

stem confi

g

uration for each PLC t

y

pe are obe

y

ed. This information can be found

in the appropriate hardware manual.

For eas

y

use and identification, each additional I/O unit should be labeled with the appropriate

I/O numbers usin

g

the provided number labels.

Caution when using an FX system with FX-8ER, FX-24MR units

• When an FX-8ER or an FX-24MR are used an additional 8 points (as 4 inputs, 4 outputs)

of I/O must be allowed for. This is because both units split blocks of 8 inputs and 8

outputs to obtain a ph

y

sical 4 input/ 4 output confi

g

uration. Hence, an FX-8ER unit

actuall

y

occupies 8 input points and 8 output points even thou

g

h there are onl

y

4

ph

y

sical inputs and 4 ph

y

sical outputs.

Addressing Special Function Blocks

Special function blocks are allocated a lo

g

ical ‘station/block number’ from 0 to 7. This is used

b

y

the FROM/TO instructions to directl

y

access each independent special function module.

The lower the ‘station/block number’ is, the closer to the base unit it can be found. Special

function blocks can be added at the users discretion but the rules of confi

g

uration for each t

y

pe

of PLC must be obe

y

ed at all times. The confi

g

uration notes can be found in the appropriate

hardware manual for each pro

g

rammable controller.

POWER

FX-16EX

POWER

FX-8EX

POWER

FX-8EYT

POWER

FX-8EYR

FX-48MR

X0-27

X30-X37 X40-X57 X60-X67

Y0-Y27

Y30-Y37 Y40-Y47

FX Series Programmable Controllers