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the controller to be an IBM PC or compatible running MicroSoft QuickBasic or equivalent. The
designation of the particular type of IEEE-488 interface card is arbitrary as most of the 488/GPIB
compatible devices can be used though each interface has its own unique command syntax and
therefore programs written for another interface may look different. The examples in this manual
make use of the Capital Equipment Corporation PC<>488 card.
5.6.1 Initializing
It is best to establish a known set of conditions within the Series 800 at the beginning of any
routine. This is accomplished by addressing the Calibrator as a listener, transmitting the Select
Device Clear which performs a Reset function,
'Reset Series 800
CALL TRANSMIT("UNT UNL MTA LISTEN 12 SDC 13 10", Status%)
A Reset message leaves all registers in the default power up state. If a reset or power up
initialization fails, the Serial Poll byte will consist of all ones and most of the time may be read to
determine this fact.
Next, it is desirable to place the Series 800 in the REMOTE state, and to verify the calibrator
is in the safe Standby condition. This is accomplished by Serial Polling the Series 800 and examining
the Status Byte to see which bits are set.
'1500 mili second wait loop
TimeStart = TIMER
DO WHILE TIMER - TimeStart < 1.5
LOOP
'Place Series 800 in the Remote Mode
CALL SEND(12, "R", Status%)
'Serial Poll to determine when the Series 800 is in Remote
DO WHILE(Poll% AND 128) = 0
CALL SPOLL(12, Poll%, Status%)
LOOP
Each task the µProcessor is requested to perform takes a finite period of time during which
the processor is unavailable for other tasks. The busy bit of the status byte is used for the purpose of
determining whether the µProcessor is prepared to accept further instructions.
In this routine a 1500 millisecond wait is encountered to allow the establishment of the Reset state. It
takes the µP about 1 to 1.5 seconds to establish the Reset conditions during which time the interface
is not available for communication. This wait can be left out or made longer as the case requires. In
the above code example the syntax Call Send(12, "R", Status%) sends the REMOTE message to the
Series 800 Calibrator at address 12. Please not that these routines are only examples, many
alternates can be derived. A further elaboration on this routine would be to add an abort routine in
the event the device does not reach the REMOTE state in a reasonable period of time followed by an
operator alarm etc.
5.6.2 Establishing an Active Defined Condition
With the Series 800 in the Standby state an instruction may be issued to program the
Calibrator for 120 Volts, 600 VA, unity PF, 60 Hz and 1% deviation range. This would be
accomplished by the following program step.
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