Filter
Top Products
Theory of IEC HSBY Operation
840 USE 106 00 January 2003 49
Overall PLC Scan
Time
The overall scan time for the IEC HSBY supporting PLC type is outlined in the IEC
Scan Time Increase Table below.
PLC to CHS Data
Transfer Rate
Calculating the PLC specific data transfer rate in a Hot Standby system leads to the
following result.
State RAM The following table lists the number of bytes required for reference storage
IEC Scan Time Increase
CPU - HSBY Baseline Configuration Scantime Increase because of HSBY
CPU 434 12 / CPU 534 14
0x: 1536, 1x: 512, 3x: 512, 4x: 1872
IEC-HSBY registers (3x): 700
~ 40 ms
CPU 434 12 / 534 14 1.9 ms / byte
Coil (0x) 3 bits
Discrete (1x) 3 bits
Input Register (3x) 2 bytes
Holding Register (4x) 2 bytes plus 2 bits
IEC HSBY Register (3x) 2 bytes