На stroke card (вибросита) указаны такие показатели
Screen Serial No
Date Taken
Card Location on Screen
Reference Line
F = Stroke Angle
S = Stroke Length

Об этом stroke есть еще такие упоминания (приведу несколько для контекста):
Stroke and angle of throw readings at each corner of the screen may be slightly different, this is not unusual as the means of measurement requires practice, consult Schenck if variations exceed 5% of reading for cards made by an experienced operator.

Normal stroke at 1000 rev/min exciter speed: 6mm

The Bed depth and transport velocity are influenced by many factors such as: screen configuration, exciter speed, stroke length, stroke angle, material infeed rate and feed material properties (ie Lumpy, wet, dry, sharp particles).

When a screen is started (or shut down) the screen’s vibrating frequency will coincide briefly with the natural frequency of the spring suspension system and spring resonance will occur. The Screen drive motors are sized to quickly accelerate the screen through the expected spring resonance zone, however during shut down the screen will take 1-2 minutes to coast to a standstill. As the screen passes slowly through the spring resonance zone the stroke length will increase considerably, this is normal and at low speed does no damage unless the screen impacts upon stationary objects.

The angle of throw is selected at time of initial design depending on the material to be handled, the inclination of the deck, the deck apertures’ size and shape (larger openings may require a steeper stroke angle), the screening effect (gentle; smaller angle, sharp; larger angle).

Тогда непонятно, что имеют в виду, когда употребляют stroke and angle readings. Просто опускают слово "длина"? Тогда это показатели длины и угла хода? А такое вообще бывает?