Making communication table

boschow · #1 20-Feb-2008, 16:01

I am trying to make some sort of communication between two home made PLC's "micro controllers". Since my communication protocol will send the bits first and only then the registers I need two tables one for bits and the other for registers. In my code there is a single structure called TNNvvar. This structure can access to other structures like inputs, outputs, pid ... See example below:

CPP / C++ / C Code:

typedef struct
{
   TNSA_DigitalInputs    DigitalInputs;
   TNSA_DigitalOutputs  DigitalOutputs;
   TNSA_AnalogInputs    AnalogInputs;
   TNSA_AnalogOutputs  AnalogOutputs;
}TNSA_MainModule;

typedef struct
{
   TNSA_MainModule    MainModule;        
   TNSA_Module01       Module01;
   TNSA_Module02       Module02;
   TNSA_Module03       Module03;
}TNNvar;

Each of this "sub" structures has registers and bits as show in the example for digital inputs:

CPP / C++ / C Code:

typedef union
{
   struct
  {
    unsigned a_bs:1;   //digital input status
    unsigned s_ac:1;   // digital input active simulation
    unsigned s_enb:1; // digital input simulation enable
    unsigned alm_enb:1; // digital input alarm enable
    unsigned t_od_enb:1; // digital input enable timer on delay
  }bit;
  unsigned int all; // i put here 16 bits because maybe i will need to add additional bits ... 
}TNSA_DigitalInputs_BBN;
typedef struct
{
TNSA_DigitalInputs_BBN bb_var;
unsigned int t_od; //timer on delay
unsigned long t_al;  //alarm timer
}TNSA_DigitalInputs;

My idea of communication table for bits is :

CPP / C++ / C Code:

#define NUMBER_OF_COILS 1600

typedef struct _PDU_COIL_MAP
{
    unsigned char *base_addr;
    unsigned char byte_index;
    unsigned char bit_index;
}PDU_COIL_MAP;

TNNvar coils;
PDU_COIL_MAP server_coil_map[NUMBER_OF_COILS]={
{&coils.MainModule.DigitalInput.bb_var.bit, 0, 0},
{&coils.MainModule.DigitalInput.bb_var.bit, 0, 1},
{&coils.MainModule.DigitalInput.bb_var.bit, 0, 2},
{&coils.MainModule.DigitalInput.bb_var.bit, 0, 3},
{&coils.MainModule.DigitalInput.bb_var.bit, 0, 4},
{&coils.MainModule.DigitalInput.bb_var.bit, 0, 5}
};

My idea of communication table for registers is :

CPP / C++ / C Code:

#define NUMBER_OF_REG 2000

typedef struct _PDU_REG_MAP
{
    unsigned int *reg;
}PDU_REG_MAP;

TNNvar registers;

PDU_REG_MAP server_reg_map[NUMBER_OF_REG]={
{&registers.MainModule.DigitalInput.t_od},
{&registers.MainModule.DigitalInput.t_al}
};

The function for data transfer has a prototype like this:

CPP / C++ / C Code:

signed int CSS_SocketSent(int socket, const unsigned char  *data, unsigned int length);

My problem is that I don't know how to make the pointer for data transferring, and if my idea of communication tables is the correct one. Can somebody help me with this.

Best regards,
BoSCHoW.

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