Agilent Technologies 75000 SERIES B, E1301B, E1300B user manual Print P, Sre?

Service Request Enable Register

The Service

Request Bit

Clearing the Service

Request Enable

Register

The following program reads the system instrument’s Status Byte register using the GPIB Serial Poll command.

10 P= SPOLL(70900)	Read Status Byte Register using
	Serial Poll, place weighted sum
	in P
20 PRINT P	Print weighted sum
30 END

The Service Request Enable register is used to "unmask" bits in the Status Byte register. When an unmasked Status Byte register bit is set to ’1’, a service request is sent to the computer over GPIB.

The command used to unmask Status Byte register bits is:

*SRE < mask>

where < mask> is the decimal weight of the bit to be unmasked, or is the sum of the decimal weights if multiple bits are to be unmasked. For example, executing:

*SRE 16

unmasks the message available (MAV) bit in the Status Byte register. Sending:

*SRE 48

unmasks the message available (MAV) and event status bit (ESB).

You can determine which bits in the Status Byte register are unmasked by sending the command:

*SRE?

This command returns the decimal weighted sum of all unmasked bits.

Note that the Service Request bit (bit 6) in the Status Byte register does not have a mask. Bit 6 is set any time another Status Byte register bit is set. If the other bit which is set is unmasked, a service request is generated.

The Service Request Enable register mask is cleared (each bit masked except bit 6) by sending the command:

*SRE 0

If *PSC 1 has been executed, the Service Request Enable register mask is cleared when power is cycled. If *PSC 0 has been executed, the mask is unchanged when power is cycled. (*PSC? queries the setting.)

Controlling Instruments Using GPIB 6-5