In this paper the expressions of the Volland, s model of large-scale convection electric field revised by using the experimental data measured on board the satellite GEOS-2 and other sounders are summarized, and with this model the field-aligned currents are calculated. The expressions for the calculated field-aligned currents from the electric potential function are applied to the case of weakly disturbed conditions. The results of calculation are consistent with the observations by the satellite Triad (Iijima and Potemra, 1978). This means that the revised Volland, s model is reasonable and hence the magnetospheric dynamical characteristics derived from GEOS-2 are reliable.