4.5 Commands
4 – 41
NTC Calibration Model
TMDN(?)
{
z
}
Set (query) the NTC sensor model
{
to
z
=
(
BETA 0
,
SHH 1
,
NONE 2
)
}
.
Two temperature models for NTC thermistors are supported by the
LDC500. The default,
TMDN
BETA
, models
R
(
T
) as:
R
(
T
)
=
R
0
e
β
(1
/
T
−
1
/
T
0
)
where
T
is temperature in kelvin (note, however, that the LDC500
always receives and displays temperature in degrees Celsius),
R
0
is the thermistor resistance at reference temperature
T
0
, and
β
is a
constant of the thermistor. The second model supported,
TMDN
SHH
,
is due to Steinhart and Hart:
1
/
T
=
A
+
B
ln
R
+
C
(ln
R
)
3
where
T
is again in kelvin,
R
is in ohms, and
A
,
B
, and
C
are the
so-called Steinhart-Hart coe
ffi
cients. Finally, if no calibration coe
ffi
-
cients are known, or the user desires to operate in resistance control
mode, the model can be set to
TMDN
NONE
.
Note that
TMDN
cannot be changed if the TEC is on and in CT mode.
TMDN
can only be set if the sensor type is NTC.
Front panel:
468JK3M6K
.
TMDN?
Example:
BETA
RTD Calibration Model
TMDR(?)
{
z
}
Set (query) the RTD sensor model
{
to
z
=
(
ALPHA 0
,
NONE 1
)
}
.
RTDs use a simple linear resistance model, given by
R
/
R
0
=
1
+
α
T
where
T
is temperature (in Celsius),
R
0
is the resistance at
T
=
0
◦
C,
and
α
is the sensitivity. If the calibration coe
ffi
cients are unknown,
or the user desires to operate in resistance control mode, the model
can be set to
TMDR
NONE
.
Note that
TMDR
cannot be changed if the TEC is on and in CT mode.
TMDR
can only be set if the sensor type is RTD.
Front panel:
4633>3NO
.
TMDR ALPHA
Example:
LDC500 Series Laser Diode Controllers
Содержание LDC500
Страница 14: ...xii General Information LDC500 Series Laser Diode Controllers...
Страница 50: ...2 22 Getting Started LDC500 Series Laser Diode Controllers...
Страница 128: ...4 64 Remote Operation LDC500 Series Laser Diode Controllers...
Страница 136: ...5 8 Error Messages LDC500 Series Laser Diode Controllers...
