2.2 Front Panel Control
27
2.2.2.2 Settings
In the five
Settings
modes, the numeric display presents a user‑adjustable
parameter. In these modes, numeric entry buttons are enabled for user
input. The rotary knob, activated by a knob press, can be used to incre‑
ment or decrement individual digits.
Int Freq
Set the frequency (in Hz) of the internal oscillator (0 Hz –
23.1 kHz).
Phase
Set the phase (in degrees) of the selected control track rel‑
ative to the frequency source. Sets the
Rel Phase
when the
Rel
indicator is lit. See Section 2.2.6.
n
Set the frequency multiplier,
𝑛 = 1, 2, 3, … 200
. See Mul‑
m
Set the frequency divisor,
𝑚 = 1, 2, 3, … 200
. See Multi‑
VCO FS
Set the full‑scale range over which the internal oscillator
is tuned as the VCO input varies from 0 V–10 V
dc
.
The
Phase
setting is always presented in units of
°
opt, where 360
°
opt
corresponds to one cycle of the selected
Control
track. (In
Shaft
con‑
trol, 360
°
opt is equivalent to 360
°
mech, since
𝑛
slots
= 1
for calculational
purposes). The phase setting entered by the user is mapped to the range
𝑛
slots
×
(‑360
°
, +360
°
) using modulo division before being stored inter‑
nally.
In
chop mode
, the
Phase
displayed on the front panel will undergo an‑
other modulo operation (modulo 360
°
), to present the optical phase from
‑359.99
°
to 359.99
°
.
In
shutter mode
, the phase will be displayed in the range [0
°
,
𝑛
slots
× 360°
).
This shutter phase will be rendered with two digits for the slot number
[0,
𝑛
slots
−1
] and three digits for the optical phase [0
°
, 360
°
). For example,
with
𝑛
slots
= 5
, a
Phase
setting of 735
°
will be rendered as
±8.8.8.8.8.8.
2
15
(since
2 × 360° + 15° = 735°
).
Entry of the phase setpoint in
shutter mode
either by numeric keypad or
remote command expects a single value in
°
opt. However, the phase
value displayed on the front panel (as slot angle remainder)
can be directly edited via the rotary encoder knob (either the slot number
or the angle remainder digits can be selected for direct editing).
SR542 Precision Optical Chopper
