Wavelength Electronics WTC3293, Техническое описание и руководство по эксплуатации

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WTC3243 TEMPERATURE CONTROLLER
SET THE SENSOR GAIN JUMPER
The Sensor Gain Jumper allows the user to amplify sensor
voltage. The minimum recommended signal is 250 mV in
order to meet published specifications. Figure 8 shows the
jumper location and Figure 9 shows the jumper position.
• If the sensor voltage is in the acceptable range, use
the 1X position and the sensor signal will pass through
without amplification.
• If the sensor voltage is very low, such as when using
a low resistance thermistor (< 2.5 kΩ) or RTD (100 Ω),
move the jumper to the 10X position to amplify the
sensor feedback signal by a factor of ten.
• Sensor signal at SEN+ (TB4) should not exceed V
DD
- 2V.
1X
10X
GAIN GAIN
Factory Default
Figure 9. Sensor Gain Jumper Settings
SET THE PROPORTIONAL GAIN AND
INTEGRATOR TIME CONSTANT
NOTE: This step must be done without the WTC3243
installed to allow for accurate resistance readings. The
Proportional Gain (P GAIN) and Integrator Time Constant
(I TERM) can be adjusted during operation, but resistance
readings will not match the table if the WTC3243 is installed.
P GAIN
I TERM
Figure 10. Location of the P GAIN and I TERM Trimpots
Table 5 suggests starting points for P GAIN and I TERM
depending on your sensor type. To optimize control, refer
to Tech Note
TN-TC01: Optimizing Thermoelectric Control
Systems
.
Table 5. Proportional Gain and Integrator Time Constant
Starting Suggestions
SENSOR TYPE P GAIN
(A / V)
P GAIN
TRIMPOT
RESISTANCE
(R
P
)
TP5 & TP6
I TIME
CONSTANT
(I
TC
)
I TERM
TRIMPOT
RESISTANCE
(R
I
)
TP6 & TP7
Thermistor 10 11.1 kΩ 3 seconds 21.4 kΩ
100 Ω Platinum
RTD
50 100 kΩ 1 second 120 kΩ
LM335 25 33.3 kΩ 2 seconds 35.9 kΩ
AD590
(Attach a 10 kΩ
resistor across
Sen+ and Sen-)
25 33.3 kΩ 2 seconds 35.9 kΩ
To adjust the P GAIN, use an ohmmeter to measure
resistance between Test Points 5 and 6 (TP5 & TP6).
Adjust the P GAIN trimpot to the desired resistance; see
Table 5
for suggested starting points. An online design
calculator is available to assist in determining resistance
values.
www.teamwavelength.com/support/design-tools/wtc-calculator/
Or use Equation 1 to calculate the P GAIN trimpot
resistance.
Equation 1. Calculating R
P
from P GAIN
R
P
=
(
100,000
)
[ Ω ]
100 - 1
PGAIN
Equation 2. Calculating P GAIN from R
P
PGAIN =
(
100
)
[A / V]
100,000 + 1
R
P
Where:
R
P
is in Ohms (Ω)
PGAIN is in Amps / Volts (A / V)