subroutine hedset(ihead)
c
c prompts from the terminal, whether you want head 1 (radial), 
c 2 (+z), or 3 (-z) data
c
c v1.0      jfej      oct 81
c v1.1  jfej      9 dec 81      use of deluns
c v1.2       jfej      14 apr 82      different syntax - type r, + or -.
c v1.3  jlg       14 sept 82      added the electrometer
c
      byte ic
      common/deluns/lundat,luni,luno
c
   10 ihead=0
      write(*,50)
   50 format(' R(adial), +(z), -(z), E(electrometer) ? ', $)
      read(*,55)ic
   55 format(a1)
      if(ic.eq.'R'.or.ic.eq.'r')ihead=1
      if(ic.eq.'+')ihead=2
      if(ic.eq.'-')ihead=3
      if(ic.eq.'E'.or.ic.eq.'e')ihead=4
      if(ihead.eq.0)go to 10
      return
   99 continue
      stop
      end