Fluke 2620A, 2625A Event Status and Event Status Enable Registers, Status Byte Register, Name

Using the Computer Interface	4
General Information (RS-232 and IEEE-488)

Bit

0

1,2,3

4

5

6

7

Name

IEB

not used

MAV

ESB RQS/MSS not used

Table 4-4. Status Byte Register

Description

Instrument Event Bit. When any bit in the Instrument Event Register is set and the corresponding mask bit(s) in the Instrument Event Enable register is set, this Instrument Event Bit in the Status Byte will be set.

When read, the Instrument Event Bit is recomputed based on the new value from the Instrument Event Register and its mask, the Instrument Event Enable Register.

Message Available

Event Status Bit

Request Service/Master Summary Status

Event Status and Event Status Enable Registers

The Event Status Register (ESR) records specified events in specific bits. (See Figure 4- 4 and Table 4-5). When a bit in the ESR is set (i.e., 1), the event that corresponds to that bit has occurred since the register was last read or cleared. For example, if bit 3 (DDE) is set to 1, a device-dependent error has occurred.

The Event Status Enable Register (ESE) is a mask register that allows the host to enable or disable (mask) each bit in the ESR. When a bit in the ESE is 1, the corresponding bit in the ESR is enabled. When any enabled bit in the ESR changes from 0 to 1, the ESB bit in the Status Byte Register also goes to 1. When the ESR is read (using the *ESR? query) or cleared (using the *CLS command), the ESB bit in the Status Byte Register returns to 0.

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 1 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 (1), the instrument sets the SRQ line true (1), which generates a service request. The eight bits of the Status Byte Register (as read by the *STB? query) are described in Table 4-4.

4-19