From 2ea516d84bf2902928700e7188eb39f5236d5cca Mon Sep 17 00:00:00 2001
From: Douglas Clowes <dcl@ansto.gov.au>
Date: Tue, 28 Aug 2012 16:00:32 +1000
Subject: [PATCH] Add virtual motors for initial energy (vei) and wavelength
 (vwi) and for elastic_time r3713 | dcl | 2012-08-28 16:00:32 +1000 (Tue, 28
 Aug 2012) | 1 line

---
 .../config/motors/motor_configuration.tcl     | 78 +++++++++++++++----
 1 file changed, 64 insertions(+), 14 deletions(-)

diff --git a/site_ansto/instrument/pelican/config/motors/motor_configuration.tcl b/site_ansto/instrument/pelican/config/motors/motor_configuration.tcl
index 3ec13de1..783f3231 100644
--- a/site_ansto/instrument/pelican/config/motors/motor_configuration.tcl
+++ b/site_ansto/instrument/pelican/config/motors/motor_configuration.tcl
@@ -865,20 +865,70 @@ proc motor_set_sobj_attributes {} {
 }
 # END MOTOR CONFIGURATION
 
-# According to http://www.nexusformat.org/Design units must conform to
-# http://www.unidata.ucar.edu/software/udunits/udunits-1/udunits.txt
-# So we use "count" for dimensionless decimal numbers
-#set vc_units count
-#make_coll_motor_2 c1 section_1 pc1 pc2 $vc_units
-#make_coll_motor_1 c2 section_2 pc3 $vc_units
-#make_coll_motor_1 c3 section_3 pc4 $vc_units
-#make_coll_motor_1 c4 section_4 pc5 $vc_units
-#make_coll_motor_1 c5 section_5 pc6 $vc_units
-#make_coll_motor_1 c6 section_6 pc7 $vc_units
-#make_coll_motor_1 c7 section_7 pc8 $vc_units
-#make_coll_motor_1 c8 section_8 pc9 $vc_units
-#make_coll_motor_1 c9 section_9 pc10 $vc_units
-#unset vc_units
+# virtual Motors
+
+# Convert mtth angle to Wavelength in Angstroms
+proc get_vwi {} {
+  set dd 3.35416
+  set angle [expr 0.5 * [SplitReply [mtth]]]
+  set wavelength [expr 2.0 * $dd * sin($angle * 3.141592654 / 180.0)]
+  return $wavelength
+}
+
+# Convert mtth angle to Energy in mEv
+proc get_vei {} {
+  set h_for_joules 6.62606957e-34
+  set neutron_mass 1.674927351e-27
+  set ev_to_joules 1.602176565e-19
+  set wavelength [expr 1.0e-10 * [get_vwi]]
+  set temp [expr ($h_for_joules / ($neutron_mass * $wavelength))]
+  set joules [expr 0.5 * $neutron_mass * ($temp * $temp)]
+  set mEv [expr 1000 * $joules / $ev_to_joules]
+  return $mEv
+}
+
+# Convert Wavelength in Angstroms to mom,mtth positions
+proc set_vwi {wavelength} {
+  set dd 3.35416
+  set theta [expr (180.0 / 3.141592654) * asin($wavelength / (2.0 * $dd))]
+  set result [format "mom=%f,mtth=%f" $theta [expr 2.0 * $theta]]
+  return $result
+}
+
+# Convert Energy in mEv to mom,mtth positions
+proc set_vei {mEv} {
+  set h_for_joules 6.62606957e-34
+  set neutron_mass 1.674927351e-27
+  set ev_to_joules 1.602176565e-19
+  set joules [expr 0.001 * $mEv * $ev_to_joules]
+  set wavelength [expr $h_for_joules / ($neutron_mass * sqrt(2.0 * $joules / $neutron_mass))]
+  return [set_vwi [expr 1.0e10 * $wavelength]]
+}
+
+MakeConfigurableMotor vwi
+vwi readscript get_vwi
+vwi drivescript set_vwi
+MakeConfigurableMotor vei
+vei readscript get_vei
+vei drivescript set_vei
+
+publish get_vwi user
+publish set_vwi user
+publish get_vei user
+publish set_vei user
+
+proc get_elastic_time {} {
+  set h_for_joules 6.62606957e-34
+  set neutron_mass 1.674927351e-27
+  set wavelength [expr 1.0e-10 * [get_vwi]]
+  set elastic_time [expr {(3.095 * $neutron_mass * $wavelength) / $h_for_joules}]
+  return elastic_time
+}
+
+MakeConfigurableMotor elastic_time
+elastic_time readscript get_elastic_time
+
+publish get_elastic_time user
 
 # Generator functions
 proc make_virtual_motor_1 { vm1 vm1_name pm1 aunits klass } {