User Manual

3.3 Local Real Time Controller
RS-485
7000 module
RS-485
7521sertes
(address-1)
7000 module
RS-485
7000 module
RS-485
7520
Host PC
RS-232
RS-485
7521series
(address-n)
7000 module
The 7000 series modules are slave devices; the control programs are
implemented in host PC. The working steps are given as follows:
1. PC sends out commands to 7000 modules for input data.
2. PC analyzes this input data & generates some output data
3. PC send out commands to 7000 modules for output data
If there are hundreds of 7000 modules, the PC will take a long time to
analyze & control these modules.
The control program can be implemented in a local 7521series. The PC
only has to send control arguments to the 7521 series, the 7521 series will
control the local 7000 modules based on these control arguments. In this way,
the PC can handle thousands of 7000 modules with the 7521 series.
Some control functions are timing critical. The local 7521 series can handle
these functions without the PC in real time.
7521/2/2A/3/4/7 Series Hardware User’s Manual, Ver. 1.5 Sep/2002, 7Mh-001-15 -----67