GYS Gysmeter Mode D'emploi page 16

Symmetry measuring (cross-measuring)
Before starting to measure it is important to check the setting of the measuring arm, see p.15
Measuring symmetry of a vehicle does not differ in any significant extent from the length
measuring (p.15). Symmetry measuring uses basically the same procedure.
IMPORTANT: NEVER measure symmetry and check height deviations at the same time.
The reason for this is that the height measurement value can be affected by the lateral
inclination of the vehicle. It is, however, important that the height measuring rod is
adjusted to the same height applicable to length
In all other aspects, the same procedure as in length measuring applies.
1. Read the height dimension given on the datasheet and select a suitable height rod. Mount
the height rod in the measuring head.
2. Mount the given socket/tip at the top of the height rod or the next even numbered socket
if the datasheet shows a socket with uneven number.
3. Read the value given on the display and compare it with the values on the datasheet.
4.
Mount the magnetic attachment on the chosen magnet point on the vehicle. Pull out and
adjust the measuring arm so that the selected measurement point can be reached.
It can be advantageous here to use the hold feature to freeze the measurement value,
especially if it is difficult to see the display while measuring. Press the HOLD key briefly to
freeze the measurement value. To return, press the HOLD key again briefly.
5. Read the measuring arm's display and compare the symmetry (cross) measurement value
with the value on the data sheet.
It can be advantageous here to enter the measured value in the data sheet table in order to
(
create a before or after report.)
Repeat the same procedure on the corresponding measurement points on the other side of the
vehicle (measuring line no 3).
Note that the vehicle can have different measurement values for the right and left side,
depending on the design of the vehicle.
Comparing heights
You can compare heights with the help of the level included on the arm.
When comparing heights, there are several important points to bear in mind:
• Place the vehicle as horizontal as possible, from one side to the other (laterally), or this can
have an influence on the accuracy of the height measurement.
• Always measure the height at the same time as length (measure parallel to the vehicle's
central line).
• The water level on the arm is fixed which often means that it is not on the same level as the
vehicle to check. This means that the measuring values stated for the height rod on the
datasheets are intended for the setting of the arm when length measures are done.
Height measurements by comparison :
Adjust the height rod until the bubble of the level is at the exact centre (this measure shall be
made on lines 1 and 4 of the datasheet only).
Move the arm over to the other side of the vehicle, setting it on the corresponding points. If
the bubble is not in the centre, there might be a possible height difference.
Read off the height rod scale and adjust up or down to be able to read the difference in
height.
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measuring.