8-25
An additional piece of information is contained in the centisecond byte. The most significant bit
indicates whether Limit Trigger monitoring was continuous between the last record and this record.
If the bit is 1, then this is the first record recorded after a power-down, reset or download and all
unfinished durations prior to this record are lost. If the bit is 0, then recording was continuous
between the last record and this one.
The next four bytes are a bitmap for the Current State of the Value 1 Comparisons of the Limits.
The first bit (the most significant bit of the first byte) is the Current State of the 1st Limit’s Value 1
Comparison. The last bit (the least significant bit of the fourth byte) is the Current State of the
32nd Limit’s Value 1 Comparison. Abit value of 1 means that the Comparison is exceeded (less
than or equal to Value 1 for a below limit; greater than Value 1 for an above limit), a bit value of 0
means the Comparison is not exceeded (greater than Value 1 for a below limit; less than or equal to
Value 1 for an above limit).
The next four bytes are the same bitmap as above, but for the Current State of the Value 2
Comparisons of the Limits.
The next four bytes are a bitmap for the Delta of the Value 1 Comparisons of the Limits. The order
of the bits is the same as above. Abit value of 1 means that the State of the Value 1 Comparison
changed since the last alarm occurred; a bit value of 0 means that the State of the Value 1
Comparison did not change since the last alarm.
The next four bytes are the same bitmap as above, but for the Delta of the Value 2 Comparisons of
the Limits.
The next four bytes are a bitmap for the Current State of the Combinations of the Limits. The first
bit (the most significant bit of the first byte) is the Current State of the 1st Limit’s Combination of
the Value 1 Comparison and the Value 2 Comparison. The last bit (the least significant bit of the
fourth byte) is the Current State of the 32nd Limit’s Combination of the Value 1 Comparison and
the Value 2 Comparison. Abit value of 1 means that the Combination is true; a bit value of 0
means that the Combination is false.
The last four bytes are the same bitmap as above, but for the Delta of the Combination of the
Limits.
Last Alarm Snapshot (40977-41104)
The Registers store the latest Limit Snapshot Log.
The record formats are also explained in Chapter 6.
Record Format: ARecord contains 32, 64, 128 or 256 bytes, depending on how many channels
have limits assigned to them. The first eight bytes in each Record are the Time Stamp. The format
of the Time Stamp is shown below.
The remaining bytes are the values monitored by Limits (45077-45204). If the first Data Pointer is
requesting VBN, a 4-byte value, then the next 4 bytes in the Record is VBN. This continues, Data
Pointer for Data Pointer, until all Data Pointers have been satisfied, or the number of bytes is equal
to the Historical Log 1 Record Size.