Abstract: A totalizer apparatus, used with belt scales and other flow rate measuring devices producing output signals subject to zero drift, maintains an auxiliary totalizer register during zeroing operations so that should zero flow conditions be interrupted during such an operation, a correct total can still be maintained. This enables autozeroing operations to be implemented, for which purpose a further auxiliary totalizer is used to test for an extended absence of flow before permitting initiation of an autozeroing operation. If a zeroing operation results in an apparently excessive zero correction, it is rejected and assumed that flow has restarted during the operation; the first auxiliary totalizer register is used to update a primary register.