I have adapted one old Fortran application to DLL and made input interface
in Excel. I have to send array of variables to that DLL and get back array
of results.
Here's a part:

'FORTRAN SUBROUTINE ZFAK(TITLE, NT, TT, IA, X1, P1, P2, DELP, MP, X2, PP,
P, RP, Z, Z1,WMA, DENS, GRAV, PPCAT, PPC, TPCC, TPC, RT, M1)

and in VBA macro
Call ZFAK("naslov", NT, TT, IA, X1, P1, P2, DELP, MP, X2, pp, P, RP, z, z1,
WMA, DENS, GRAV, PPCAT, PPC, TPCC, TPC, RT, M1)

input variables: "naslov", NT, TT, IA, X1, P1, P2, DELP, MP
output variables X2, pp, P, RP, z, z1, WMA, DENS, GRAV, PPCAT, PPC, TPCC,
TPC, RT, M1
X1 and X2 are arrays [x1(12), x2(12)]

Thanks