Series PC Manual V 1.0 - Rev. 3
– 03/01/01
DS Europe
14
9.4. RESOLUTION
The transducer is digitally measuring the cursor position: It practically divides the
measured lenght into many “steps”.
Every internal step correspond to a real lenght of 0,046mm: the transducer is practically
measuring by doing a “step” counting.
For the internal measured “step” corresponds to 0.046 mm, it cannot measure
displacement variations smaller than 0.046 mm and for this reason it is the measuring
error that the transducer can commit when measuring the cursor position.
Dividing the measuring length, expressed in mm, by 0.046 and keeping only the whole part
of the result we can get a good approximation of the length value expressed in the
measuring unit inside the transducer.
The analog output has a 16 bit resolution. This means that theoretically it can divide its
output interval (0-10V, 4-20mA) by 65535 points, corresponding, for example, to a
∆
V
minimum of 152
µ
V; effectively the real minimum variation (
∆
V or
∆
A) of the analog output
is depending on the distance between the zero point (calibrated with TxZ control, for the
cursor “x”) and the full scale point (calibrated with TxF control) expressed in the measuring
unit inside the transducer, for this value is the number of distinct points that the transducer
can resolve between two positions.
If the transducer was to have a measuring field equivalent to 1000 mm and voltage output
of 0-10V, we would have:
Example 1
: Suppose that we calibrate, with reference to the PCS hexagonal head, the
zero position at 0 mm and the full scale at 1000 mm.
∆
Vmin = 10V/((1000-0)/0.046) = 0.00046 V
Example 2
: Suppose that we calibrate, with reference to the PCS hexagonal head, the
zero position at 25 mm and the full scale at 90 mm.
∆
Vmin = 10V/((90-25)/0.046) = 0.007077 V
It means that, the shorter the distance between the zero point and the full scale point, the
greater the analog output
∆
Vmin corresponding to a cursor displacement of 0.046 mm.
In the version for measuring level “L”, the measurement has a resolution of ± 0,15 mm.
9.5. NUMBER OF CURSORS
The transducers have a self-detecting function to detect the number of cursors applied to
the measuring probe (
one or two
).
As soon as the transducer is turned on, it detects how many magnets are present on the
probe and automatically sets the analog outputs enabled by the user during the
personalisation procedure.
FS
1
= 1000 mm
FS
2
= 90 mm
Zero
2
=
25 mm
Zero
1
=
0 mm
