If you have been using optical levels, like the Topcon AT-B4A or the Topcon AT-B3A, and you need the next step up in accuracy for your levelling work then you need to consider investing in a Digital Level like the Topcon DL-502. The Topcon DL-502 is the more accurate Digital Level in the Topcon Range.
Both the Digital Levels produced by Topcon share the magnetically dampened pendulum action compensator which has a working range of 30 minutes (or half a degree), this provides stability when working on busy construction sites or next to busy roads. All Topcon Digital Levels feature “Wave-and-Read” technology which enables the RAB-Code staff to be waved back and forth, allowing the digital level to automatically read the correct height. This is the minimum reading when the staff is perfectly plumb (or vertical). Also the RAB-Code staff can be inverted and used to gather heights of bridges or ceilings or other hard to measure locations. The Topcon DL-502 also features on-board programmes for various measurement routines for quick calculation of elevation, height difference, ceiling height and even cut/fill differences.
The main advantage with using a digital level is to maximise work efficiency whilst minimising the potential human error involved in any levelling exercise, this should enable consistent measurement precision speed. With a single button operation, the Topcon DL-502 will read the height and the distance from the staff and then record the data. The Topcon DL-502 can hold up to 2000 measurements. This can be downloaded later in the office with the use of the Topcon Magnet Office Tools software.
The Topcon DL-502 shows an erect image at 32x magnification and has a minimum focussing distance of just 1.5m, allowing for very close measurements to be taken. The quoted measuring range of the Topcon DL-502 is between 1.6m to 100m from the digital level, however this can vary depending upon the weather conditions. Accuracy for the Topcon DL-502 for a 1km double run levelling exercise is just 0.6mm when using an Invar Staff, 1.0mm when using a Fibreglass Staff and 1.0mm when doing optical readings using a E-Grad Staff.
The Topcon DL-502 has a IPX4 rating, which means that it does not have a rating for dust but can withstand water spray from up to 60degrees from vertical. The Topcon DL-502 will operate for up to 16 Hours or almost 2days on site and can operate from temperatures as low as -20Degrees Celsius to as high as 50Degrees Celsius.
Expect to pay around £2,500+VAT for a new Topcon DL-502 Digital Level from leading survey equipment suppliers and then you would need to specify which Invar Staff would be right for you at an additional cost.