Wavelength Electronics WTC3293, Datasheet And Operating Manual

Page: 27 / 36

© 2022 www.teamWavelength.com 27
WTC3243 TEMPERATURE CONTROLLER
SET THE CONTROL LOOP PROPORTIONAL
GAIN RESISTOR
The control loop Proportional Gain can be set by inserting a
resistor, R
P
, between PGAIN (Pin 5) and +1V (Pin 6) to set
PGAIN from 1 to 100.
Table 11 lists the suggested resistor values for R
P
versus
sensor type and the ability of the thermal load to change
temperature rapidly.
Table 11. Proportional Gain Resistor R
P
vs. Sensor Type and
Thermal Load Speed
PROPORTIONAL
GAIN RESISTOR R
P
PROPORTIONAL
GAIN ( A / V)
SENSOR TYPE /
THERMAL LOAD
SPEED
4.99 kΩ 5 Thermistor / Fast
24.9 kΩ 20 Thermistor / Slow
100 kΩ 50 RTD / Fast
Open 100 RTD / Slow
24.9 kΩ 20 AD590 or LM335 / Fast
100 kΩ 50 AD590 or LM335 / Slow
Use Equation 9 to calculate R
P
from PGAIN.
Equation 9. Calculating R
P
from PGAIN
R
P
=
(
100,000
)
[ Ω ]
100 - 1
PGAIN
To calculate PGAIN from R
P
use Equation 10 .
Equation 10. Calculating PGAIN from R
P
PGAIN =
(
100
)
[A / V]
100,000 + 1
R
P
SET THE CONTROL LOOP INTEGRATOR TIME
CONSTANT
To set the control loop Integrator Time Constant (I
TC
), insert
a resistor, R
I
, b1V (Pin 6) and I (Pin 7) to set I
TC
from 0.53 to 4.5 seconds.
Table 12 lists the suggested resistor values for R
I
versus
sensor type and the ability of the thermal load to change
temperature rapidly.
Table 12. Integrator Time Constant vs. Sensor Type and
Thermal Load Speed
INTEGRATOR
RESISTOR R
I
INTEGRATOR
TIME CONSTANT
(SECONDS)
SENSOR TYPE /
THERMAL LOAD
SPEED
21.4 kΩ 3 Thermistor / Fast
13.3 kΩ 4.5 Thermistor / Slow
Open 0.53 RTD / Fast
112 kΩ 1 RTD / Slow
112 kΩ 1 AD590 or LM335 / Fast
13.3 kΩ 4.5 AD590 or LM335 / Slow
Equation 11 demonstrates how to calculate a value for
R
I
given a desired integrator time constant. The Integrator
Time Constant, I
TC
, is measured in seconds.
Equation 11. Calculating R
I
from I
TC
R
I
=
(
100,000
)
[ Ω ]
(1.89) I
TC
- 1
Equation 12 demonstrates how to calculate the I
TC
, given
a value for R
I
.
Equation 12. Calculating I
TC
from R
I
I
TC
= (0.53)
(
100,000 + 1
)
[Seconds]
R
I