Rules for Using Communication Functions on M340 CPUs

M340 CPUs use EF and procedure type communication functions.

Legacy Communication Functions Available on M340 CPUs

Legacy communication functions role:

Name

Role

DATA_EXCH

Transmit or receive data.

INPUT_BYTE

Receive an array of bytes on a character mode link of a BMX NOM module in a local rack or linked to a CPU embedded communication channel.

INPUT_CHAR

Receive a character string on a character mode link of a BMX NOM module in a local rack or linked to a CPU embedded communication channel.

PRINT_CHAR

Send a character string on a character mode link of a BMX NOM module in a local rack or linked to a CPU embedded communication channel.

READ_VAR

Read the value of one or more language objects via a communication module in a local rack or linked to a CPU embedded communication channel.

SEND_EMAIL

Send an email over an Ethernet port of a communication module plugged in a local rack.

WRITE_VAR

Write the value of one or more language objects via a communication module in a local rack or linked to a CPU embedded communication channel.

Other Communication Functions Available on M340 CPUs

Other communication function role:

Name

Role

ETH_PORT_CTRL

Activate or deactivate a protocol.

GET_TS_EVT_M (1)

Get the time stamped data in a Modicon BMX ERT 1604T module plugged in a local rack.

1: GET_TS_EVT_M is part of the System Library (SysClock family).

Utility Functions Available on M340 CPUs

These functions are executed synchronously. A function is synchronous when it is completely executed during the CPU task that activated this function.

Utility functions role:

Name

Role

ADDM

Convert a character string into an address that can be used directly by the communication functions READ_VAR, WRITE_VAR, DATA_EXCH and PRINT_CHAR.

CANCEL

Interrupt an asynchronous communication function in progress.

NOTE: Another way to cancel an asynchronous communication function in progress is to use the cancel bit of the management parameters.