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

Page: 85 / 438

Programming the HP E1415 for PID Control 85 Chapter 3
return to Trig Idle State.
Outputting Trigger
Signals
The HP E1415 can output trigger signals on any of the VXIbus TTLTRG
lines. Use the OUTPut:TTLTrg<n>[:STATe] ON | OFF command to select
one of the TTLTRG lines and then choose the source that will drive the
TTLTRG line with the command OUTPut:TTLTrg:SOURce command. For
details see OUTP:TTLTRG commands starting on page 224
To output a signal on the TTLTRG1 line each time the Trigger Timer cycles
execute the commands:
TRIG:SOUR TIMER
select trig timer as trig source
OUTP:TTLTRG1 ON
select and enable TTLTRG1 line
OUTP:TTLTRG:SOUR TRIG
each trigger output on
TTLTRG1
INITiating/Running Algorithms
When the INITiate[:IMMediate] command is sent, the HP E1415 builds the
input Scan List from the input channels you referenced when you defined the
algorithm with the ALG:DEF command above. The module also enters the
Waiting For Trigger State. In this state, all that is required to run the
algorithm is a trigger event for each pass through the input-calculate-output
cycle. To initiate the module, send the command:
INIT
module to Waiting for Trigger
State
When an INIT command is executed, the driver checks several interrelated
settings programmed in the previous steps. If there are conflicts in these
settings an error message is placed in the Error Queue (read with the
SYST:ERR? command). Some examples:
•
If TRIG:SOUR is not TIMer then ARM:SOUR must be IMMediate.
•
The time it would take to execute all algorithms is longer than the
TRIG:TIMER interval currently set.
Starting the PID
Algorithm
Once the module is INITiated it can accept triggers from any source
specified in TRIG:SOUR.
TRIG:SOUR TIMER
(*RST default)
ARM:SOUR IMM
(*RST default)
INIT
INIT starts Timer triggers
or
TRIG:SOUR TIMER
ARM:SOUR HOLD
INIT
INIT readies module
ARM
ARM starts Timer triggers.
... and the algorithms start to execute.