ICP DAS USA PMC-523 Series, Руководство пользователя

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ICP DAS PMC-523x/PMC-224x/PMD Series User Manual
232
Appendix I
：
Modbus Address Table
PMC/PMD allows SCADA software or HMI device to retrieve the power data, I/O
channel data and system information via Modbus TCP/RTU protocol. PMC/PMD
register addresses are specified according to Modbus register mapping tables (more
detailed information will follow).
Please Note:

The addresses are in Base 0 format

The addresses are in Decimal format

The default value of NetID is 1, and you can modify the NetID value in the
Network Setting page. (Please refer to 6.2 Network Setting ).

If the data is displayed in Floating format, each record of data will take two
registers to hold the data. The following code example demonstrates how to join
the two registers into one floating point value.
For the compilers are different (big endian or little endian) the floating point
composing order might be different. For example: if r1 represent the address of
30100 register and r2 represent the address of 30101 register, to join r1 and r2 to
a floating point, if the system is big endian system you will need to call:
float value = register_to_float(r1, r2);
On the other hand, if the system is little endian system, you will need to call:
float value = register_to_float(r2, r1);
Please Note:
1. If you are not sure your compiler belongs to which system, try both ways
to find the accurate one.
2. The way to join the two registers value into DWORD is similar to
Floating point; change the return value to DWORD or Unsigned Long.
float register_to_float(short r1, short r2)
{
float f;
int *a = &f;
*a = r1;
a++;
*a = r2;
return f;
}
}