GE Multilin F650 Instruction Manual page 417

B.1 MODBUS PROTOCOL FOR 650
B.1.5.1 CONTROL EVENTS
This section explains events set aside for control, not to be confused with the "snap shot events" , which are used for
debugging tasks.
The event is the value change from 0 to 1 or from 1 to 0 of one bit. Associated to a time label, which shows when that
change was performed.
In the F650, any status or combination of status may generate an event. For this, the F650 have 192 bits capable of
generate control events.
The first 128 may be configured through a table from EnerVista 650 Setup menu: Setpoint, Relay configuration, or for
complex configurations by PLC Editor.
The other 64 bits comes from the 16 possible switchgears, which generate 4 bits of status each one:
- Open(52B ON, 52A OFF)
- Close(52A ON, 52B OFF)
- Error 00(52A&52B OFF)
- Error 11(52A&52B ON)
B
Internally the events buffer is a circular FIFO of 255 events. The addresses for managing this FIFO are:
- 0x03FF:
- 0xFCFF:
- 0xFD00 to 0xFDFF:
In the 0x03FF address it is stored the event number of the following new event that it is going to be generated. For
instance, if the number 7677 is stored, it means that the last event stored is the number 7676. This value, at the beginning
is 0 and it is increased as soon as events from 0 to 2^12 + 1 carry bit are generated.
Carry bit allows knowing whether the F650 has been started, as when it starts, either for lack of power supply or for a
configuration change, the carry bit is set to 0. When events are generated, the event number will be increased up to a
maximum value of 0x1FFF; in the next event the number will be 0x1000, that is, the bit of carriage will get always to 1, until
a new F650 start up. The next figure shows it:
B-14
Number of the following event
(To know whether there are new events)
Access from the oldest event
Access to any of the events (circular queue)
0 x 0 0 0
0 x 1 F F F
F650 Digital Bay Controller
0 x 1 0 0 0
0 x 1 7 F F
APPENDIX B
GE Multilin