MOGlabs MWM, Manual, Page: 72 / 96

64
Appendix D. Command language
pressure (NTP, 20
◦
C and 1 atm. 101.325 kPa). Returns current units if no
argument given.
D.2 PID control
set
pid,set,val
Set the desired wavelength sepoint. The current value is returned if no
val
is given.
val
should be a floating-point number in whatever units the
MWM
device will be measuring. There is no provision for providing units
or for conversion if the display units are changed after setting the
PID
setpoing.
For example, to lock the laser frequency to the rubidium-85 D2 line at
780.243 nm (in vacuum), 384.230 THz. If the device is displaying in
nm
(vac)
, the set value should be 780.243. If the display units are later
changed to
THz,
the
MWM
will initially display 380.230 THz but the
PID
controller will drive the laser towards 780.243 THz; thus the setpoint
should first be changed to 380.230.
kp, ki, kd
pid,kp,val
or
pid,ki,val
or
pid,kd,val
Set the
PID
coefficients
k
p
, k
i
, k
d
(see chapter 5). The current value is
returned if no
val
is given, for example,
pid,kp
.
val
should be a floating-
point number from 0 to 1.0.
min, max
pid,min,val
or
pid,max,val
Set the minimum and maximum output limits from the
SMA
connector, in
volts. The current value is returned if no
val
is given, for example,
pid,min
.
val
should be a floating-point number from
−
5 to +5.
offset
pid,offset,val
Set the output offset voltage; that is, the voltage on the
SMA
connector
when the measured wavelength matches the setpoint. The current value
is returned if no
val
is given.
val
should be a floating-point number from
−
5 to +5.
gain
pid,gain,val
Set the output gain in volts/unit. For example, if the
MWM
is displaying in
nm (vac)
, driving a moglabs laser system with
DLC
controller, a reasonable