HP VXI 75000 C Series, User'S And Scpi Programming Manual

Page: 58 / 438

58 Programming the HP E1415 for PID Control Chapter 3
After INIT (and with trigger events occurring), the DSP is busy measuring
input channels, executing algorithm code, sending internal algorithm values
to the CVT, and updating control outputs. To insulate the DSP from
commands that would interrupt its algorithm execution, the HP E1415’s
driver disallows execution of most SCPI commands after INIT. The driver
does allow certain commands that make sense while the module is running
algorithms. These are the commands that read and update algorithm
variables, retrieve CVT and FIFO data, and return Status System values. The
Command Reference Section (Chapter 6) specifies whether a command is
accepted before or after INIT.
The next section in this chapter ("Executing the Programming Model")
shows the programming sequence that should be followed when setting up
the HP E1415 to run algorithms .
Executing the Programming Model
This section shows the sequence of programming steps that should be used
for the HP E1415. Within each step, most of the available choices are shown
using command sequence examples, with further details available in the
Before INIT
After INIT
Commands Accepted:
Commands Accepted:
Trigger Idle
State
Waiting for
Trigger State
Input,
Execute Algs,
Output
*RST or ABORT?
no
no
yes
yes
Trig Count
Exhausted?
All commands exept:
*TRG, TRIGGER, and ALG:UPD:CHAN
INITiate[:IMM]
Power-On
*RST
ABORT
Most of ALG subsystem
ARM[:IMM]
FETCH?
FORMAT
SENSe:DATA ...
STATus ...
SYSTem ...
*TRG & TRIGger[:IMMediate] (if TRIG:SOUR is HOLD)
TIMer or other
trigger event
Figure 3-2. Module States