Experimental Physics and
Industrial Control System

Rolf Keitel <[email protected]> · Tue, 28 Aug 2001 10:08:08 -0700

In the recent debate on conversions, someone mentioned doing new analog
record types in a future release. Just to muddy the waters a bit more:
I always disliked specifying linear conversions by giving ranges or
EGUF,EGUL, because it forces you to come up with phantom numbers if the
control voltage range of a device doesn't match the DAC/ADC ranges or if
you have to deal, for example, with a 5 V DAC and a 10 V ADC.
I had an old control control system, where we spec'd the conversions in
two stages:
- volts/bit and volt_offset to take care of the DAC/ADC
- egu/volt and egu_offset to take care of the device.
For efficiency, these two sets of values were combined into one
calculation, but it was also possible to display the voltage values,
which was quite helpful for the techs who probed the breakout panels
with their DVMs.
Just food for thought.
- rolf -
-- 
+-------------------------------------------------+
| Rolf Keitel, TRIUMF         Tel: (604) 222-7453 |
| Group Leader ISAC Controls  Fax: (604) 222-7307 |
| and Electronics Development                     |
| Vancouver, B.C., Canada                         |
+-------------------------------------------------+

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System