Wavelength Electronics LDTC0520, Техническое описание и руководство по эксплуатации

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LDTC0520 / LDTC1020 LASER DIODE AND TEMPERATURE CONTROLLER
TEMPERATURE CONTROL LOOP TUNING
The PI loop parameters are designed to work for a wide
range of loads and applications. The factory defaults are:
R
P
= R5 = 24.9 kΩ [P
GAIN
= 20 A / V]
R
I
= R6 = 31.6 kΩ [I
TIME-CONSTANT
= 2.2 seconds]
Table 6 lists the suggested resistor values for R
P
versus
sensor type and the ability of the thermal load to change
temperature rapidly.
Table 6. Proportional Gain Resistor R
P
vs. Sensor Type and
Thermal Load Speed
SENSOR TYPE /
THERMAL LOAD
SPEED
PROPORTIONAL
GAIN RESISTOR R
P
PROPORTIONAL
GAIN ( A / V)
Thermistor / Fast 4.99 kΩ 5
Thermistor / Slow 24.9 kΩ 20
RTD / Fast 100 kΩ 50
RTD / Slow Open 100
AD590 or LM335 / Fast 24.9 kΩ 20
AD590 or LM335 / Slow 100 kΩ 50
Use Eq. (4) to calculate R
P
(in Ω) from P
GAIN
.
R5 = R
P
=
100000
(4)
100
-1
PGAIN
To calculate P
GAIN
(in A / V) from R
P
use Eq. (5) .
100
(5)
PGAIN = 100000
+1
R
P
To locate R
I
and R
P
on Rev C only, refer to Figure 22 .
Figure 22. R
P
and R
I
Component Locator (Topside of Board)
Product Rev C only
Table 7 lists the suggested resistor values for R
I
versus
sensor type and the ability of the thermal load to change
temperature rapidly.
Table 7. Integrator Time Constant vs. Sensor Type and
Thermal Load Speed
SENSOR TYPE /
THERMAL LOAD
SPEED
INTEGRATOR
RESISTOR R
I
INTEGRATOR
TIME CONSTANT
(SECONDS)
Thermistor / Fast 21.4 kΩ 3
Thermistor / Slow 13.3 kΩ 4.5
RTD / Fast Open 0.53
RTD / Slow 112 kΩ 1
AD590 or LM335 / Fast 112 kΩ 1
AD590 or LM335 / Slow 13.3 kΩ 4.5
Eq. (6) demonstrates how to calculate a value for R
I
(in Ω)
given a desired integrator time constant. The Integrator Time
Constant, I
TC
, is measured in seconds.
R6 = R
I
=
100000
(6)
(1.89 · I
TC
) ‑ 1
Eq. (7)
demonstrates how to calculate the I
TC
, given a value
for R
I
.
I
TC
= 0.53
(
100000
+1
)
(7)
R
I
To locate R
I
and R
P
on Rev
A
&
B
only, refer to
Figure 23
.
R
P
R
I
Figure 23. R
P
and R
I
Component Locator (Topside of Board)
Product Rev A & B only