FX Series Programmable Controllers

Devices in Detail 4

Assigning grouped bit devices:

As already explained, bit devices can be grouped into 4 bit units. The “n” in KnM0 defines the number of groups of 4 bits to be combined for data operation. K1 to K4 are allowed for 16bit data operations but K1 to K8 are valid for 32bit operations.

K2M0, for example identifies 2 groups of 4 bits; M0 to M3 and M4 to M7, giving a total of 8 bit devices or 1 byte. The diagram below identifies more examples of Knuse.

X37 X36 X35 X34 X33 X32X31X30

X16 X15 X14 X13 X12 X11 X10 X7

X6

X5

X4

X3

X2

X1

X0

0

1

0

0

0

1

0

0

0

1

1

0

1

0

0

1

1

0

1

1

0

 

 

 

 

 

 

 

 

 

 

 

 

K1X6

 

 

 

 

K1X0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

K3X0

 

 

 

 

 

 

 

 

 

 

 

 

K8X0

 

 

 

 

 

 

 

 

 

 

 

 

K1X0

:

X0 to X3 4 bit devices with a head address of X0

K1X6

:

X6 to X11 4 bit devices with a head address of X6

K3X0

:

X0 to X13 12 bit devices with a head address of X0

K8X0

:

X0 to X37 32 bit devices with a head address of X0

Moving grouped bit devices:

If a data move involves taking source data and moving it into a destination which is smaller than the original source, then the overflowing source data is ignored. For example;

If K3M20 is moved to K1M0 then only M20 to M23 or K1M20 is actually moved. The remaining data K2M24 or M24 to M31 is ignored.

Assigning I/O:

Any value taken from the available range of devices can be used for the head address ‘marker’ of a bit device group. However, it is recommended to use a 0 (zero) in the lowest digit place of X and Y devices (X0, X10, X20.....etc). For M and S devices, use of a multiple of “8” is the most device efficient. However, because the use of such numbers may lead to confusion in assigning device numbers, it recommended to use a multiple of “10”. This will allow good correlation to X and Y devices.

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Mitsubishi Electronics FX1S manual Moving grouped bit devices, Assigning I/O, Assigning grouped bit devices