Fluke 2635A user manual Status Byte Register STB, Bit Event Status Register ESR Name Description

Computer Operations 4

Computer Interface Commands and Operation

associated Logical OR gate will output a logic high to the Event Status Bit (ESB) in the Status Byte Register.

For example, an ESR byte of binary 00010000 (decimal 16) indicates an Execution Error. If the ESE register is set to binary 00010000 (using the command *ESE 16), then an Execution Error condition will cause the Logical OR gate to output a logic high. In a similar manner, parameters can be combined. An ESR byte of binary 00110000 (decimal

48)and an ESE set to a corresponding binary 00110000 (using the command *ESE 48), will cause the Logical OR gate to have a logic high output for any of two conditions: Command Error or Execution Error.

Other commands include *ESR?, which returns the decimal equivalent of the ESR byte and then clears the register to zero, and *ESE?, which returns the decimal equivalent of the ESE byte. The command *CLS will clear all event registers. (See Appendix E for an 8-bit binary-coded decimal table.)

Bit

0

1

2

3

4

5

6

7

	Table 4-2. Event Status Register (ESR)
Name		Description
OPC		Operation Complete. set true (1) upon execution of the *OPC
		command, indicating that the instrument has completed all selected
		pending operations
not used		Always set to 0.
QYE		Query Error. Sets the QYE bit of the ESR. Example would be *IDN?;
		*ESR? (vs. *ESR?; *IDN?). This causes the “?>“ prompt to be
		returned.
DDE		Device Dependent Error. Generated true (1) by overflows of the RS-
		232 input buffer or by calibration errors. This causes the “!>“ prompt
		to be returned.
EXE		Execution Error. Generated true (logic 1) by parameters out of
		bounds or by a valid command that could not be processed due to
		an internal condition (such as calibration commands being received
		when calibration is not enabled). This causes the “!>“ prompt to be
		returned.
CME		Generated true (1) by syntax errors, including: unrecognized
		command and incorrect command sequences. This causes the "?>"
		prompt to be returned.
not used		Always set to 0
PON		Power Transition. Set true (logic 1) after an off-to-on transition has
		occurred in the instrument’s power supply.

Status Byte Register (STB)

The inputs to the Status Byte Register (STB) include the Instrument Event Bit, Event Status Bit, and Message Available Bit. In addition, the STB register generates a Master Summary Status. Each input is described in Table 4-3. The output byte (except for bit 6) is ANDed with the output byte of the corresponding Service Request Enable Register (SRE). When there is a logic high correlation between any of the bits of the STB and SRE registers, the associated Logical OR gate will output a logic high that is used as a Master Summary Status (MSS) bit.

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