Wavelength Electronics WTC3293, Datasheet And Operating Manual

Page: 22 / 36

© 2022 www.teamWavelength.com 22
WTC3243 TEMPERATURE CONTROLLER
OPERATING WITH RTD TEMPERATURE SENSORS
An RTD sensor has good linearity, relatively small size, a temperature
range of -260º to +850º C, but poor sensitivity.
Resistive temperature sensors should connect one terminal as close
as possible to GND (Pin 13) to avoid parasitic resistances and voltages
affecting temperature stability and accuracy.
The diagrams on this page demonstrate how to configure the WTC3243 for
operation with a Platinum RTD temperature sensor. An online calculation
utility to determine resistances is available at:
www.teamwavelength.com/support/design-tools/wtc-calculator/
Figure 18. RTD / Thermoelectric Operation -- Top View
Figure 19. RTD / Resistive Heater Operation -- Top View
IF YOU ARE UPGRADING FROM THE WHY5640: The position of Pin 1 on the WHY5640 is reversed (or mirrored) relative
to the position of Pin 1 on the WTC3243.
TOP VIEW
V
S
V
DD
TIE GROUND CONNECTIONS DIRECTLY TO PIN 13
1
WTC3243
Temperature
Controller
1
2
3
4
5
6
7
14
13
12
11
10
9
8
Actual
Temperature
Monitor voltage
V
DD
R
T
(RTD
)
R
BIAS
R
I
R
P
R
LIMA
R
LIMB
R
G
Adjusting PI
Control Loop
Adjusting Limit
Currents
V
SET
VSET = Sensor Resistance X Sensor Bias Current X 10, for 100 Ω RTDs
1
1
1
+
-
NOTE: Removing R
G
and grounding
Pin 8 will add an internal sensor gain
of 10.09. Pin 9 will read 10 times less
than Pin 2. If used with the evaluation
PCB, Pin 9 will match Pin 2.
V
DD
Bandgap
Voltage
Reference
W
CCW
OR OR
D/A
TOP VIEW
V
S
V
DD
TIE GROUND CONNECTIONS DIRECTLY TO PIN 13
1
WTC3243
Temperature
Controller
1
2
3
4
5
6
7
14
13
12
11
10
9
8
Actual
Temperature
Monitor voltage
V
DD
R
T
(RTD
)
R
BIAS
R
I
R
P
R
LIMA
1.5 k Ω
R
G
Adjusting PI
Control Loop
Adjusting Limit
Currents
V
SET
VSET = Sensor Resistance X Sensor Bias Current X 10, for 100
Ω
RTDs
1
1
1
NOTE: Removing R
G
and grounding
Pin 8 will add an internal sensor gain
of 10.09. Pin 9 will read 10 times less
than Pin 2. If used with the evaluation
PCB, Pin 9 will match Pin 2.
NC
V
S
V
DD
Bandgap
Voltage
Reference
W
CCW
OR OR
D/A
QUICK CONNECT LEGEND
DIAGRAM
REFERENCE
TABLE OR EQUATION
R
LIMA
Table 9 on page 25
R
LIMB
Table 9 on page 25
R
P
Table 11 on page 27
R
I
Table 12 on page 27
R
BIAS
Table 10 on page 26
Equation 6 & Equation 7
R
T
Sensor datasheet
R
G
Table 10 on page 26
Equation 8