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Detecting Measurement Events In The 2001 Instruments that complied with the IEEE-488.1 standard used a Serial Poll Byte to return important information about internal functions of the instrument. The 2001 on the other hand, which complies with the IEEE-488.2 standard, no longer uses a Serial Poll byte. It contains many status registers. These registers include a Standard Event, Operation Event, Arm Event, Sequence Event, Trigger Event, Measurement Event, and a Questionable Event register. There is also a Status Byte register which is used to summarize the status of a few of the previously mentioned event status registers. The status byte register of the 2001 should not be confused with the status byte register used on IEEE-488.1 compliant instruments. The Measurement Event Status Register is a latched, 16-bit read-only register whose bits are set by the Measurment Event Condition register and Transition filter. Once a bit is set, it will remain set until the register is cleared by a specific operation. The Measurement Event Status Register is composed of the following conditions: Bit 11 Buffer Pretriggered Weighted value = 2048 Bit 10 Buffer Overflow Weighted value = 1024 Bit 9 Buffer Full Weighted value = 512 Bit 8 Buffer Half Full Weighted value = 256 Bit 7 Buffer Available Weighted value = 128 Bit 6 Voltmeter Complete Weighted value = 64 Bit 5 Reading Done Weighted value = 32 Bit 4 High Limit 2 Weighted value = 16 Bit 3 Low Limit 2 Weighted value = 8 Bit 2 High Limit 1 Weighted value = 4 Bit 1 Low Limit 1 Weighted value = 2 Bit 0 Reading Overflow Weighted value = 1 These bits generally will provide the most usable information that a user will need. As an example, suppose the 2001 is collecting data into the data buffer and you would like to know when the buffer is full. To permit the Measurement Event Status register to latch the Buffer Full bit, the Measurement Event Positive Transition Filter must be masked such that when the rising edge of the Buffer Full bit of the Measurement Event Condition register occurs, the Buffer Full bit in the Measurement Event Status register is latched. A complete figure of the Measurement Event Status registers is attached to help understand the process. The example code below illustrates this example ( code is written using the CEC format ): '** Set Positive &NegativeTransition Filters here, send *CLS to clear '** status model cmd$ = ":Status:Measure:Ptransition 512; Ntransition 0" Call Send(GPIBAddress, cmd$, status%) cmd$ = "*CLS" Call Send(GPIBAddress, cmd$, status%) ' '***Code to start reading process is placed here ' '**** Check for Buffer Full here Do cmd$ = ":Status:Measure:Event?" 'Query Measure Event Status Call Send(GPIBAddress, cmd$, status%) Call E