Pepperl+Fuchs Blog

PGV Absolute Positioning System vs. Magnetic Tape Guidance Systems

Posted by Gerry Paci on Mon, Apr 29, 2019

pepperl fuchs pgvEfficient intralogistics requires automated guided vehicles (AGVs) to move with speed and precision through warehouses or factory floors, avoiding obstacles and navigation errors. Navigation technology is essential to ensuring an AGV and the product it is carrying make it to their destination in one piece. One of the most popular types of AGV guidance technology is tape. The two types of AGV navigation tape are nonmagnetic tape, which can be comprised of Data Matrix codes or just solid color, and magnetic tape.

Magnetic and nonmagnetic tapes both have advantages and disadvantages, as do the AGV sensors that read them. Nonmagnetic AGV guidance systems like our position guided vision (PGV) and magnetic tape guidance systems differ in performance in the following ways:


The tape’s flexibility affects how easy or challenging its installation can be. In many AGV applications, the travel path is rarely a straight line. Magnetic tape is not flexible like its counterparts—Data Matrix coded tape and colored tape. Magnetic tape’s inflexibility requires it to come in various segments that differ in length, radius, and shape to fit each application. Nonmagnetic tape can easily be installed for turns and added to existing nonmagnetic tape pathways.

Read Head Size

A magnetic tape reader can range in length from 200 mm to 600 mm. At under 100 mm in length, the PGV read head has a much smaller foot print. It can be installed on the smallest of AGVs.

Output Information/Data

The PGV system gives users a plethora of output data. Data Matrix codes encompass a large amount of digital information in a small 15 x 15 mm square. The PGV grants users access to X position, Y tolerance, angle, and speed. Accurate angular feedback and Y axis positional information is provided from the colored tape. Magnetic tape readers only give either X position or offset position from the guideline center.


Magnetic tape guide sensors typically have a limited range. When customers need a longer range, duplicate segments must be added, and a counter must be used in the PLC to increment.

PGV has a range of up to 10 km.

Reading Distance

A normal reading distance for an AGV magnetic tape sensor is up to 20 mm. A nonmagnetic tape sensor, such as our PGV, can read up to 150 mm.

The PGV can track colored tape in red, blue, green, or yellow in widths of up to 40 mm. Readability of the lines is unaffected by background color or reflectivity. This is because the PGV is tuned to focus directly on the region of interest, ignoring outside influences like light or glossy floors in the background.


The PGV guidance system has an accuracy of up to 0.2 mm. It is the norm for magnetic tape readers to have an accuracy of 1 mm—few can go lower than >0.1 mm. Going that low is typically not practical for positioning an AGV.


Magnetic tape readers are limited in speed. Most can only have a read speed up to 7 m/s while the PGV can go up to 8 m/s. The PGV allows AGVs to safely travel up to 17 mph.


Magnetic tape is extremely durable—there is generally no need to protect it, and it takes heavy damage to remove the magnetic tape reader’s ability to output position.

Learn More About PGV/safePGV

Topics: PGV, AGV

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