HP 5501A Operating And Service Manual page 24

Three linear measurement techniques are available with the Laser Transducer: the 10702A
Linear lnterferometer for normal usage; the 10705A Single Beam lnterferometer for non-
contacting applications or usage when space is severely limited in the measurement path;
and the 10706A Plane Mirror Interferometer.
The plane mirror interferometer technique is uniquely suited for monitoring the motion of
X-Y stages. Measurements taken using this technique are immune to pitch or yaw of the
moving stage a s X and Y are measured in the same plane. The technique is also useful for
many non-contacting applications.
Output formats are also varied. The Laser Transducer can be interfaced to virtually any mini-
computer controller (including the HP Model 21MX computer) and many "hardwired" con-
trollers. Interfaces to HP Calculators are easily accomplished a s well.
For readout, numeric displays are also available with the Laser Transducer System. Other capa-
bilities include automatic compensation, the ability to monitor changing atmospheric con-
ditions and provide wavelength corrections (due to the changing velocity-of-light) to the con-
troller or displays. Included in this automatic compensation package is the additional capa-
bility to compensate for the thermal expansion and contraction of machine or workpiece.
1.12 CONFIGURING A 5501A LASER TRANSDUCER SYSTEM
Use the following information on configuring a 5501A Laser Transducer System to determine
and record exactly what equipment is present in your system. You can then use that record to
determine the specific information in this manual that is directly applicable to your system.
For an overview of the various possible configurations see Figure 7-7.
a. LASER. All systems are based on one 5501A Laser Transducer. This instrument houses
the laser source and its associated circuitry. It also produces the reference signal and
provides diagnostics of the laser source (refer to Table 7-2).
b. CHOOSE ACCESSORIES FOR EACH AXIS OF MEASUREMENT (up to four axes). As illus-
trated in Figure
7-7,
three accessories are required to be mounted on each machine axis;
an interferometer, a reflector, and a 10780A Receiver. When the 10702A Linear Interfer-
ometer is used, the 10703A Retroreflector serves a s its reflector. For the 10705A Single
Beam Interferometer, the reflector may be either a flat reflective surface, or the 10704A
Retroreflector. The 10706A Plane Mirror lnterferometer is designed to be used in con-
junction with high-quality plane mirror reflectors (refer to Table 7-2).
The 10780A Receiver is a photodetector/preampIifier package which senses the laser
beam and generates the measurement signal (refer to Table 7-2).
c. CHOOSE OPTICS TO DIRECT LASER BEAM TO MEASUREMENT The 10707A
Beam Bender and 10700A/10701A Beam Splitters are designed to "pipe" a portion of
the laser beam to each axis (refer to Table 7-2).