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dd_modtcp.c File Reference

This module contains the device driver for accessing a Modicon PLC using the drvModtcp driver. More...

Defines
#define	ERROR   (-1)
#define	logMsg   printf
Functions
INT	modtcp_init (HNDLE hKeyRoot, INT *index, INT channels)
	This function initializes the Modicon PLC communication channel..
INT	modtcp_exit (INT index)
	Shuts down driver.
INT	modtcp_set (INT index, INT addr, unsigned short value)
	Sets the value of the passed address in the PLC to the passed value.
INT	modtcp_get (INT index, INT addr, unsigned short *pValue)
	Gets the value for a location in the PLC.
INT	modtcp (INT cmd,...)
	The driver interface for the class driver code.

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Detailed Description

This module contains the device driver for accessing a Modicon PLC using the drvModtcp driver.

It provides an initialization function which accesses the ODB to determine the PLC addresses and initializes the drvModtcp driver. There are also set and get functions for the specific registers in the PLC.

The original drvModtcp driver was written for vxWorks, so there are some translations for Linux and NT versions of the code.

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Define Documentation

#define ERROR   (-1)

#define logMsg   printf

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Function Documentation

INT modtcp (  INT    cmd, ...    )

The driver interface for the class driver code. Valid commands for this function are CMD_INIT, CMD_EXIT, CMD_SET, CMD_GET. Parameters: cmd  the command to be processed

INT modtcp_exit (  INT    index )  [static]

Shuts down driver.

INT modtcp_get (  INT    index, INT    addr, unsigned short *    pValue )  [static]

Gets the value for a location in the PLC. If there is an error from the read (typically a broken socket) then make one attempt to reconnect. Parameters: index  the index of the PLC addr  the address of the register to read in the PLC pValue  pointer to value to be returned

INT modtcp_init (  HNDLE    hKeyRoot, INT *    index, INT    channels )  [static]

This function initializes the Modicon PLC communication channel.. The ODB contains all the parameters for the definition of the interface. This information is located under /Equipment/"EquipmentName"/Settings/Devices/"EquipmentName" where "EquipmentName" is the name of the equipment defined in frontend.c. The ODB schema is defined as: Key name Type #Val Size Last Opn Mode Value --------------------------------------------------------------------------- TecPlc DIR Name STRING 1 32 4h 0 RWD pptplc IP STRING 1 32 4h 0 RWD 142.90.xxx.xxx99 Memory INT 1 4 4h 0 RWD 1100 ReadGroupStart INT 8 4 4h 0 RWD [0] 289 [1] 33 [2] 749 [3] 17 [4] 1001 [5] 0 [6] 0 [7] 0 ReadGroupSize INT 8 4 4h 0 RWD [0] 8 [1] 6 [2] 1 [3] 4 [4] 4 [5] 0 [6] 0 [7] 0 ReadOnceStart INT 8 4 4h 0 RWD [0] 193 [1] 225 [2] 0 [3] 0 [4] 0 [5] 0 [6] 0 [7] 0 ReadOnceSize INT 8 4 4h 0 RWD [0] 8 [1] 4 [2] 0 [3] 0 [4] 0 [5] 0 [6] 0 [7] 0 WriteGroupStart INT 8 4 4h 0 RWD [0] 193 [1] 225 [2] 755 [3] 0 [4] 0 [5] 0 [6] 0 [7] 0 WriteGroupSize INT 8 4 4h 0 RWD [0] 8 [1] 4 [2] 1 [3] 0 [4] 0 [5] 0 [6] 0 [7] 0 Watchdog INT 1 4 4h 0 RWD 749 Keepalive INT 1 4 4h 0 RWD 755 The function performs the following tasks: The Network connection to the PLC is established. All Read Once Groups are set up in the shared memory All Read Groups are set up in the shared memory All Write Groups are set up in the shared memory The Watchdog and Keepalive locations are defined. The shared memory access threads are started. The Read Once groups are processed, then the read, write and watchdog threads start scanning. Parameters: hKeyRoot  the key for /Equipment/"EquipmentName"/Settings/Devices/"EquipmentName" index  the particular PLC to be initialized channels  the channel to be initialized (not used) Returns: FE_SUCCESS

INT modtcp_set (  INT    index, INT    addr, unsigned short    value )  [static]

Sets the value of the passed address in the PLC to the passed value. If clear is true then the value will be cleared after one second. Parameters: index  the index of the PLC of interest addr  the location in the 4x register space to be set. value  the data to be written

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