Function Description

The WRITE_VAR function is used to write one or more language objects of the same type:

  • internal bits

  • internal words

Verify that he objects to be written are consecutive. They may be located in a remote CPU or in a device connected to a communication channel.

The additional parameters EN and ENO can be configured.

FBD Representation

Representation:

LD Representation

Representation:

IL Representation

Representation:

LD Address
WRITE_VAR Object_Type, First_Object, Object_Number, Data_to_Write, Management_Param

ST Representation

Representation:

WRITE_VAR(Address, Object_Type, First_Object, Object_Number, Data_to_Write, Management_Param);

Parameter Description

The following table describes the input parameters:

Parameter

Type

Comment

ADR

ARRAY [0..5] OF INT for Premium

ARRAY [0..7] OF INT for Modicon M340 and M580

Specific statements by hardware platforms:

  • Premium:

    • Address of the message's receiving character mode channel is given by the ADDR function.

    • Address of the destination entity of the exchange.

      The following addresses are prohibited:

      • {Network.Station}APP,

      • {Network.Station}APP.num.

      • broadcast addresses (ALL, 0 for TSX SCY 11601 module).

  • Modicon M340:

    • Address of the message's receiving character mode channel is given by the ADDM function.

    • The syntax of the address is of ADDM ('r.m.c.node')-type.

  • Modicon M580:

    • Address of the destination entity of the write operation, result of ADDMX function.

TYP

STRING

Type of objects to write for Premium PLCs:

  • ’%M’: internal bits,

  • ’%MW’: internal words,

  • ’%S’: system bits,

  • ’%SW’: system words.

Type of objects to write for Modicon M340 and M580 PLCs:

  • ’%M’: internal bits,

  • ’%MW’: internal words.

NUM

DINT

Index of the first object to be written in the destination device.

NB

INT

Number of objects to write.

EMIS

ARRAY [n..m] OF INT

Word table containing the value of the objects to be written.

The following table describes the input/output parameters:

Parameter

Type

Comment

GEST

ARRAY [0...3] OF INT

Exchange management table consisting of the following words:

  • Rank 1 word: a word managed by the system and consisting of two bytes:

    • Most significant byte: exchange number

    • Least significant byte: activity bit (rank 0) and cancel bit (rank 1)

      NOTE: The cancel bit is only available for Modicon M340 and M580 PLCs.

  • Rank 2 word: a word managed by the system and consisting of two bytes:

    • Most significant byte: operation report

    • Least significant byte: communication report

  • Rank 3 word: a word managed by the user which defines the maximum response time using a time base of 100 ms.

  • Rank 4 word: a word managed by the system which defines the length of the exchange.

For detailed information, refer to section Structure of the Management Parameters.

NOTE: Verify that the length parameter is not initialized before launching the function.
NOTE: Premium CPU embedded Ethernet of TSX P574xxx, TSX P575xxx and TSX P576xxx used as client, can only write 100 words instead of 123 words for other Ethernet modules and Premium CPUs with ETY PORT.

Simultaneous Transactions

The following table gives the capacities of each communication channel to simultaneously process transactions according to various configurations on Micro and Premium PLCs.

Configuration

Micro

TSX 57 10

TSX 57 20

TSX 57 23/30/40/45/55, PCX 57, PMX 57

TSX 57 46/56

Uni-Telway master terminal port

4

4

4

4

8

Uni-Telway master PCMCIA or SCY link

1

8

8

8

8

Uni-Telway client slave terminal port

4

1

1

1

8

Uni-Telway client slave PCMCIA or SCY link

1

1

1

1

1

Uni-Telway server slave terminal port

4

4

4

4

4

Uni-Telway server slave PCMCIA or SCY link

4

6

6

6

6

Modbus terminal port

4

-

-

-

-

Modbus PCMCIA or SCY link

4

8

8

8

8

Character mode terminal block

1

1

1

1

1

Character mode PCMCIA or SCY link

4

8

8

8

8

CANopen PCMCIA

-

10

10

10

10

Fipway PCMCIA or SCY link

4

8

8

8

8

Modbus Plus

4

4

4

4

4

Ethernet

-

16

16

16

16

Embedded Ethernet

-

-

-

-

64

The following table gives the capacities of each communication channel to simultaneously process transactions according to various configurations on Modicon MC80 PLCs.

Configuration

BMKC80•03••

Embedded CANopen

16

Embedded Ethernet

16

Modbus master serial port

8

The following table gives the capacities of each communication channel to simultaneously process transactions according to various configurations on Modicon M340 PLCs.

Configuration

BMX P34 1000

BMX P34 2000

BMX P34 2010/ 20102

BMX P34 2020

BMX P34 2030/ 20302

Embedded CANopen

-

-

16

-

16

Embedded Ethernet

-

-

-

16

16

Modbus master serial port

8

16

16

16

-

Maximum number of requests as client per scan on Modicon M580 CPUs:

Configuration

CPU Reference (BME P58 ...)

10•0

20•0

30•0

40•0

5040

6040

Ethernet

16

32

48

80

80

96

Maximum number of requests as client per scan on Hot Standby Modicon M580 CPUs:

Configuration

CPU Reference (BME H58 ...)

2040

4040

6040

Ethernet

32

80

96

Maximum number of requests served per scan on Modicon M580 CPUs:

Configuration

CPU Reference (BME P58 ...)

10•0

20•0

30•0

40•0

5040

6040

CPU from all origin (1.)

16

24

32

40

48

64

Embedded Ethernet

8

12

16

24 (2.)

32

32

USB

4

4

4

4

4

4

1. %SW90 system word allows to adjust the number of requests served per cycle. The minimum number of requests served per cycle is set to 2 in order to reduce the CPU jitter.

2. Maximum number of requests is 16 for M580 CPU BME P58 40•0 with firmware version ≤ 1.20.

Maximum number of requests served per scan on Hot Standby Modicon M580 CPUs:

Configuration

CPU Reference (BME H58 ...)

2040

4040

6040

CPU from all origin (1.)

24

40

64

Embedded Ethernet

12

24

32

USB

4

4

4

1. %SW90 system word allows to adjust the number of requests served per cycle. The minimum number of requests served per cycle is set to 2 in order to reduce the CPU jitter.
NOTE: Verify that the maximum number of simultaneous requests given in all tables takes into account the maximum number of simultaneous requests that each CPU can manage per cycle, as Client and as Server.