the SRQ annunciator regardless of whether the condition that caused the service request continues to exist. The service request is also removed when you send the "CLR’’ command (see page 76).
Remote/Local. The power supply can receive programming information either from the
Parallel Poll. Parallel Poll allows the controller to receive at the same time one bit of data from each of up to eight instruments connected to the bus. Agilent power supplies designate bit #6, the RQS bit of the serial poll register for this operation. By checking the status of this bit, the computer can quickly determine which instruments on the bus requested service. Once an instrument is identified, the computer can perform a serial poll to find out the exact cause of the request. Parallel Poll does not reset this service request bit (RQS) in the power supply.
Note | |
| instruments such as Agilent Technologies power supplies indicate the state of their RQS bit, but the |
| operator should not assume that all instruments on the bus respond to parallel poll with their RQS bit. |
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Unless remotely configured, the power supply will respond with a 1 on one of the
The power supply may be remotely configured to respond with a 0 or 1, on any of the data lines, to indicate that it is requesting service. This is done in accordance with
Serial Poll. In a serial poll, the controller polls each instrument on the bus one at time. The power supply responds by placing the contents of the
Device Clear. The Device clear command is typically used in systems to send all devices in the system to a known state with a single command. It may be implemented as an addressed or an unaddressed command. The power supply CLR command performs the same function as Device Clear (see page 76).
GP-IB Address Selection
You can find out the present address or change the address of the supply by using the front panel ADDR key as described in Chapter 3. Any address 0 through 30 is a valid address. If you program an address outside this range you will get a number range error.
Note | Care should be taken to not select the controller address. |