此款極座標式求積儀型號為 30001，工作原理與縮放儀極座標式求積儀 (No. 7513) 類似。求積儀搭配一組縮放儀連桿，兩連桿的長度都可以調整。連桿上有兩個追蹤點，以適用於不同大小面積的量測。

This polar planimeter, model No. 30001, operates on principles similar to the Pantograph Polar Planimeter 7513. The planimeter is equipped with a pantograph, and the lengths of pantograph links can be adjusted. There are two tracing points on the pantograph, making the planimeter suitable for measuring areas in different scales of sizes.