Appendix A API Commands
ChartScan User’s Manual A-57
Contents of Calibration Status Register (CSR)
U3: Query the current system settings. This command responds with the equivalent of the following:
F?I?L?P?Q?S?T?Y?
U4: Reads the current High/Low/Last data for all configured channels. Refer to the Data Output Format section
of Appendix C for the format of the High/Low/Last response.
U5: Reads and resets the High/Low/Last data. This command performs exactly like the U4 comm and except
that it clears out the current High and Low readings for all of the configured channels.
U6: Reads the Buffer Status String. The buffer status string contains current informat ion regarding the current
state of the acquisition buffer. The current status of the acquisition buffer may be i nterrogated at any time by
issuing the Buffer Status String (U6) command. As mentioned earlier, the U6 com mand is a user query
command which will return information regarding the current state of the acquisition buffer. The acquisition buffer
holds scan data that has been initiated by one or more trigger events. This data is held in trigger blocks within
the buffer. Each trigger block defines one acquisition that has taken place. The trigger blocks may be variable in
length. The Buffer Status String command provides the interface in which the current acquisit ion buffer
configuration may be queried.
The Buffer Status String (U6) command returns the following fields:
• Blocks Available: This field represents the total number of blocks currently contained within the
buffer. The total represents the total number of blocks that have been triggered. A block need not be
complete to be included in this total, it only needs to be triggered. This field also represents t he
number of trigger blocks that the read block is behind the current write block. If there are no blocks
available, then Blocks Available will be 0000000.
• Scans Available: This field represents the total number of scans available at the time the U6
command was issued. It should be noted that pre-trigger data is not available for use until the defined
trigger event has taken place. This total represents the total number of scans available across all
blocks in the acquisition buffer. If there are no scans available in the buffer, then Scans Available will
be 0000000.
• Current Read Pointer: This field represents the current position within the current read block. This
pointer is relative to the trigger point which is always oriented at location 0. In other words if, currently,
pre-trigger scans are being read, the Current Pointer will be less than 0. Likewise, if post-trigger scans
are currently being read, the Current Read Pointer will be greater than 0. If the current scan to be read
is the trigger scan, then the Current Read Pointer will be 0000000. If the Current Read Pointer is
undefined its value will be -0999999.
• Trigger Time Stamp: This field represents the Time/Date that the trigger event occurred for the
current read block. This field takes on the same format as other time/date st amp fields described
elsewhere in this manual. If the trigger event has not occurred, then this field will have the value
00:00:00.00,00/00/00.