Counter overflow and underflow

An overflow or underflow of the counter limits is indicated by the process data 0x60n0:04 "Counter underflow" or 0x60n0:05 "Counter overflow".

• The "Counter underflow" bit in index 0x60n0:04 is set when an underflow 0x80n1:1B "Reset counter value" → 0x80n1:1A "Limit counter value" occurs. With default parameters this corresponds to "..00 → ..FF"
  It is reset if 2/3 of the counting range are underrun.
• The "Counter overflow" bit 0x60n0:05 is set when an overflow 0x80n1:1A "Limit counter value" → 0x80n1:1B "Reset counter value" occurs. With default parameters "..FF → ..00"
  It is reset if 1/3 of the counter range is exceeded.