Fluke 45 user manual Reading the Status Byte Register

Operating the Meter Using the Computer Interface	5
Service Requests (IEEE-488 Only and Status Registers

Table 5-6. Description of Bits in ESR and ESE

Bit No.

0

1

2

3

4

5

6

7

Name

Operation Complete (OPC).

Not used.

Query Error (QYE).

Device-Dependent Error (DDE)

Execution Error (EXE)

Command Error (CME)

Not used.

Power On

True (Set to 1) Conditions

All commands previous to receipt of an *OPC command have been executed. Interface is ready to accept another message.

Always set to 0.

Attempt has been made to read data from the meter’s output buffer when no output is present or pending. Or, a new command line has been received before a previous query has been read. Or, Both input and output buffers are full.

Incorrect input during calibration, or RS-232 input buffer overflow.

Command was understood but could not be executed. Result, for example, of an inappropriate parameter.

Command was not executed because it was not understood. This condition could result, for example, if a command sent to the meter contained a syntax error.

Always set to 0.

(PON) Power has been cycled off and on since the last time the ESR was read or cleared.

Status Byte Register

The Status Byte Register (STB) is a binary-encoded register that contains eight bits. Note that the Service Request Enable Register (SRE) uses bits I through 5 and bit 7 to set bit 6, the request service (RQS) bit, as enabled by the SRE. When the RQS bit is set true(l), the meter sets the SRQ line true (1), which generates a service request. The eight bits of the Status Byte Register (as read by the *STB? command) are described in Table 5-7.

Reading the Status Byte Register

The host can read the Status Byte Register by taking a serial poll or sending the meter a "*STB?" query. The value of the status byte is not affected by the STB? query. When the Status Byte Register is read, an integer is returned. This integer is the decimal equivalent of an 8-bit binary number. [For example 48 is the decimal equivalent of the binary 00110000, and means that bit 4 (MAY) and bit 5 (ESB) are set to "1".]

If the status byte is read by serial poll, bit 6 is returned as a request service (RQS); if it is read with an "*STB?" query, bit 6 is returned as Master Summary Status (MSS).

EXAMPLEEXPLANATION

*STB?	Reads the Status Byte Register. Assume that "32" is returned. Converting 32
	to the binary 00100000 indicates that bit 5 (ESB) is set to 1. To determine the
	event status, you would have to read the Event Status Register in the same
	manner, using the "ESR?" command.

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