constraint_eqn_031 Subroutine

   subroutine constraint_eqn_031(tmp_cc, tmp_con, tmp_err, tmp_symbol, tmp_units)
      !! Equation for TF coil case stress upper limit (SCTF)
      !! author: P B Lloyd, CCFE, Culham Science Centre
      !! args : output structure : residual error; constraint value;
      !! residual error in physical units; output string; units string
      !! Equation for TF coil case stress upper limit (SCTF)
      !! #=# tfcoil
      !! #=#=# fstrcase, sig_tf_case_max
      !! and hence also optional here.
      !! Logic change during pre-factoring: err, symbol, units will be assigned only if present.
      !! fstrcase : input real : f-value for TF coil case stress
      !! sig_tf_case_max : input real : Allowable maximum shear stress in TF coil case (Tresca criterion) (Pa)
      !! sig_tf_case : input real : Constrained stress in TF coil case (Pa)
      use constraint_variables, only: fstrcase
      use tfcoil_variables, only: sig_tf_case_max, sig_tf_case
      implicit none
            real(dp), intent(out) :: tmp_cc
      real(dp), intent(out) :: tmp_con
      real(dp), intent(out) :: tmp_err
      character(len=1), intent(out) :: tmp_symbol
      character(len=10), intent(out) :: tmp_units

      tmp_cc =  1.0D0 - fstrcase * sig_tf_case_max/sig_tf_case
      tmp_con = sig_tf_case_max
      tmp_err = sig_tf_case_max - sig_tf_case / fstrcase
      tmp_symbol = '<'
      tmp_units = 'Pa'

   end subroutine constraint_eqn_031