Agilent Technologies 8935 Series Bedienungsanleitung PDF herunterladen (Seite 171)

Chapter 6 171

Advanced Operations

HP-IB Service Requests

Writing the Service Request Enable Register

The Service Request Enable Register is written with the *SRE Common

Command. The *SRE command sets the bit pattern (bits 0-5 and 7) of

the Service Request Enable Register. The Service Request Enable

by bits 0-5 and 7 of the Status Byte Register, will generate a Service

Request on the HP-IB bus. The Test Set always ignores bit 6 (binary

weight 64) of the bit pattern set by the *SRE command.

The bit pattern set by the *SRE command is determined by selecting

the desired condition(s) from the Status Byte Register, setting the value

of the bit position(s) to a logical one, setting the value of all non-selected

bit positions to a logical zero, and sending the binary-weighted decimal

equivalent of bits 0-5 and 7 after the *SRE command. For example, if

the programmer wished to have the occurrence of a message available

in the Output Queue (bit position 4 in the Status Byte Register) and the

occurrence of a condition in the Hardware# 2 Status Register (bit

position 1 in the Status Byte Register) to generate a Service Request on

the HP-IB bus, the binary-weighted decimal value of the bit pattern for

the Service Request Enable Register would be determined as shown in

Table 6-11.

Example 6-107 Example

OUTPUT 714;"*SRE 18"

NOTE

The decimal value of the bit pattern must be a positive integer in the

range of 0 to 255. Sending a negative number or a number greater than

255 causes an HP-IB Error: -222 Data out of range.

Clearing the Service Request Enable Register

The Service Request Enable Register is cleared by sending the *SRE

Common Command with a decimal value of zero. Clearing the Service

Request Enable Register turns off service requests.

Table 6-11 Determining the Service Request Enable Register Bit Pattern

Bit Position76543210

Logical Value0X010010X = ignored by

the Test Set

Binary

Weighting

128 X 32 16 8 4 2 1 X = ignored by

the Test Set

Decimal Value 0+ 0+ 0+ 16+ 0+ 0+ 2+ 0 = 18

1 2 ... 166 167 168 169 170 171 172 173 174 175 176 ... 328 329

Keine Kommentare

Agilent Technologies 8935 Series Bedienungsanleitung Seite 171