DECLARE SUB hp3457cmon (c%)
DECLARE SUB hp3457cv (c%, v!)
DECLARE SUB dac488setcv (c%, v!)
DECLARE SUB idacramp (rr!, inom!)
DECLARE SUB idaccheckpar (ok$)
DECLARE SUB dac488getcv (c%, v!)
DECLARE SUB idacrampfr (rr!, fr!, ifin!)

'****************************************************************************
'Module IDAC
'This module contains drivers to set and measure the magnet current using
'the IO Tech DAC488.
'
'Zachary Wolf
'11/25/95
'****************************************************************************

'Parameters used in this module
COMMON SHARED /idac/ imagdacchanP%, imagpervdacP!, imagtstableP%, imaghpchanP%, vtransperimagP!

SUB idaccheckpar (ok$)

'****************************************************************************
'This subroutine checks that all required parameters have been assigned
'values.
'
'Output:
' ok$, "y" if parameter assignments are ok, "n" otherwise
'
'Zachary Wolf
'9/18/95
'****************************************************************************

'Default value
ok$ = "n"

'imagdacchanP%
IF imagdacchanP% < 1 OR imagdacchanP% > 4 THEN
 PRINT "IDAC: imagdacchan has improper value"
 EXIT SUB
END IF

'imagpervdacP!
IF imagpervdacP! <= 0 OR imagpervdacP! > 5000 THEN
 PRINT "IDAC: imagpervdac has improper value"
 EXIT SUB
END IF

'imagtstableP%
IF imagtstableP% < 0 OR imagtstableP% > 120 THEN
 PRINT "IDAC: imagtstable has improper value"
 EXIT SUB
END IF

'imaghpchanP%
IF imaghpchanP% < 0 OR imaghpchanP% > 9 THEN
 PRINT "IDAC: imaghpchan has improper value"
 EXIT SUB
END IF

'vtransperimagP!
IF vtransperimagP! <= 0 OR vtransperimagP! > 2 THEN
 PRINT "IDAC: vtransperimag has improper value"
 EXIT SUB
END IF

'If we made it this far, all parameters have values
ok$ = "y"

END SUB

SUB idacgeti (imag!)

'****************************************************************************
'This subroutine gets the transductor output voltage.  It then applies
'the calibration constant to get the magnet current.
'
'Output:
' imag!, the measured magnet current
'
'Zachary Wolf
'4/21/94, 1/5/95
'****************************************************************************

'Make sure all parameters have been assigned reasonable values
CALL idaccheckpar(ok$)
IF ok$ <> "y" THEN
 imag! = 0!
 EXIT SUB
END IF

'Simplify the notation
c% = imaghpchanP%
vperi! = vtransperimagP!

'Measure the voltage from the transductor
CALL hp3457cv(c%, v!)

'Apply the conversion factor
imag! = v! / vperi!

END SUB

SUB idacinit

'****************************************************************************
'This subroutine does the initial turn on of the power supply to a small
'current.
'
'Zachary Wolf
'10/1/95
'****************************************************************************

'Message
PRINT
PRINT "Initial power supply turn on."
PRINT "Ramp the supply to 5 A, stabilize, ramp to 0..."

'Ramp the supply
CALL idacramp(1!, 5!)

'Stabilize
SLEEP 5

'Ramp to 0
CALL idacramp(1!, 0!)

END SUB

SUB idacmonitor

'****************************************************************************
'This subroutine sets up the HP3457 to monitor the transductor.
'
'Zachary Wolf
'7/27/95
'****************************************************************************

'Make sure all parameters have been assigned reasonable values
CALL idaccheckpar(ok$)
IF ok$ <> "y" THEN EXIT SUB

'Set the DVM so the current can be monitored
CALL hp3457cmon(imaghpchanP%)

END SUB

SUB idacramp (rr!, inom!)

'****************************************************************************
'This subroutine supervises the ramp of the magnet current.
'
'Input:
' rr!, the magnet current ramp rate
' inom!, the desired magnet current
'
'Zachary Wolf
'1/1/95
'****************************************************************************

'Make sure all parameters have been assigned reasonable values
CALL idaccheckpar(ok$)
IF ok$ <> "y" THEN EXIT SUB

'First ramp to 90% of the desired current
CALL idacrampfr(rr!, .9, inom!)

'Next ramp to 99% of the desired current at 10% of the ramp rate
CALL idacrampfr(.1 * rr!, .9, inom!)

'Now finish the the remaining 1% of the ramp at 1% of the initial ramp rate
CALL idacrampfr(.01 * rr!, 1!, inom!)

'Let the power supply and magnet stabilize at the final current
SLEEP imagtstableP%

END SUB

SUB idacrampfr (rr!, fr!, ifin!)

'****************************************************************************
'This subroutine generates a fraction of the magnet current ramp.
'The complete ramp (fr!=1) would be from the present current to ifin!.
'This routine generates a fraction fr! of this ramp.
'The points making up the ramp are updated every 0.1 second.
'This routine can be called several times to approach the final magnet
'current at a low ramp rate.
'
'Input:
' rr!, the magnet current ramp rate
' fr!, the fraction of the ramp to be done from the present current to ifin!
' ifin!, the desired final magnet current
'
'Zachary Wolf
'4/18/94
'****************************************************************************

'Simplify the notation
c% = imagdacchanP%
iperv! = imagpervdacP!

'Define a local parameter, the time between ramp steps
dt! = .1

'Find the voltage the DAC is putting out
CALL dac488getcv(c%, vini!)

'Find the DAC final voltage we need
vfin! = ifin! / iperv!

'Compute the DAC voltage ramp rate
rrdac! = rr! / iperv!

'Compute the number of ramp points to give approximately this rate
nr% = (ABS(vfin! - vini!) / rrdac!) / dt!

'See if we need to ramp
IF nr% = 0 THEN EXIT SUB

'Find the size of each voltage step
vstep! = (vfin! - vini!) / nr%

'Compute the voltage at each step
DIM vdac!(0 TO nr%)
FOR i% = 0 TO nr%
  vdac!(i%) = vini! + vstep! * i%
NEXT i%

'Have the DAC output fraction fr! of the calculated ramp
FOR i% = 0 TO nr% * fr!
 tstep! = TIMER
 CALL dac488setcv(c%, vdac!(i%))
 WHILE TIMER - tstep! < dt!
 WEND
NEXT i%

END SUB

SUB idacsetpar (imagdacchan%, imagpervdac!, imagtstable%, imaghpchan%, vtransperimag!)

'****************************************************************************
'This subroutine sets parameter values for a DAC488 controlling a power supply.
'
'Input:
' imagdacchan%, DAC488 channel to use (1 to 4)
' imagpervdac!, magnet current per DAC volt
' imagtstable%, wait time after a ramp
' imaghpchan%, HP3457 channel for transductor read
' vtransperimag!, transductor volts per amp
'
'Zachary Wolf
'9/21/95
'****************************************************************************

'Place the parameters in the local common block for future use
imagdacchanP% = imagdacchan%
imagpervdacP! = imagpervdac!
imagtstableP% = imagtstable%
imaghpchanP% = imaghpchan%
vtransperimagP! = vtransperimag!

END SUB