HP 5335A - Page 55

Mode! 5335A
Operation and Programming
3-184. if the data contained in the OFFSET, NQRMLZ, and SCALE registers is not needed, the
30 bytes can be shortened to just 7 bytes, thus speeding the programming time. Refer to the
Programming Examples beginning with paragraph 3-209.
3-185. SRQ and Status SR
3-186. The 5335A has the ability to send a request service (SRQ) message. To enable this feature,
the controller must send the SRI command.
3-187. Request service may be sent upon any error or fail message, and may be sent at the end of
a measurement. When request service is sent the seventh bit (bit 7) is set. In addition to this bit,
one other bit is also set, representing the status or type of service requested. If service request
is not enabled, this second bit is still set, even though bit 7 is not. Table 3-7 gives the effect
of each of the status bits on the service request message. When SRQ is asserted, the 5335A will
turn on the "SRQ” annunciator.
3-188. The 5335A will only send SRQ if a measurement is ready for sending, and it is in the WAIT
mode, and it is not addressed to TALK or RFD is false.
( ( M e asurement done)
AND
(in WAIT mode)
AND
((if not addressed to TALK) or (RFD is false)]
NOTE
Constant reading of the status byte is not recommended. This
may slow down the measurement processor time.
Table 3-7, Status Bits Usage with SRQ
SR Status Bits Usage
BIT 1 (LSB)
Set when measurement is done; and 1) 5335A is in WAIT mode
and it is not yet addressed to taik, or 2) 5335A is in WAIT mode
and is addressed to talk, but listening device on bus is not yet
ready for data (RFD is false).
BIT 2 Set when external time base used.
BIT 3 Set if an ERROR has happened.
BIT 4 Set if a FAIL has happened.
BIT 6 Set when GATE is open.
BIT 7 Set if requesting service.
BIT 8 Set if in diagnostic monitor
3-189. Program Execution/Response Times
3-190. Program speed is dependent upon the 5335A > s HP-IB response time. Table 3-8
provides some NOMINAL response times for various types of commands, using the 9825A
calculator. The examples use the “wrt” instruction. Times are rounded up to 5 ms resolution.
3-39