Allocated Flags Area - Beckhoff BC7300 Manual

Bus Terminal Controller
Cycle tick counter
Fieldbus diagnostics
K-Bus diagnostics
Data acces via Modbus
40

Allocated flags area

The allocated flags area offers a variety of further additional functions and
diagnostic facilities.
The cycle tick counter starts at address %MB504. Each tick corresponds to
about 1 ms. The counter has 32 bits, and can also be written from the PLC
in order to set it to zero or to some other particular value.
Fieldbus diagnostics are located at flag words 508 and 509.
%MX508.0
The bit is set to "1" if a write telegram has been processed and no new write
telegram is sent to the Bus Terminal Controller within the watchdog time.
No other bits have any function.
K-Bus diagnostics are located at flag words 510 and 511.
%MX510.0
%MX510.1
Meaning
Flag byte
%MW508 Bit 0:
Bits 1-15:
%MW510 Bit 0:
Bit 1:
Bits 2-15:
From the firmware B4 is it as well possible to access directly reading and
writing on the flag area. This access does not trigger the watchdog. That
means values which are written in this range, remain as well after a
watchdog error set.
"TRUE" watchdog time elapsed
"TRUE" K-Bus error
"TRUE" configuration error
Fieldbus error
reserved
K-Bus error
Configuration error
reserved
BC7300