HTC4000 TEMPERA
TURE CONTROLLER
www.teamwavelength.com
© 2012
HTC4000-62400-B
PAGE 7
R
LIMIT
=
2752 * I
LIMIT
1.8864 - 0.4128 * I
LIMIT
I
LIMIT
R
LIMIT
HTC4000 with TE
1.0 A
2.0 A
3.0 A
4.0 A
1867 Ω
5188 Ω
12.7 kΩ
46.8 kΩ
10
µ
A
X
1 mA
X
X
10 mA
X
10 kΩ Thermistor
100 kΩ Thermistor
RTD
LM335
R
BIAS
=
1.225
I
BIAS
- 122
2
3
Limit +
PID OUT
Install
Jumper
for
Bipolar
Operation
2
2
1
Fixed,
Metal Film
OR
OR
LIMIT +
LIMIT -
Adjustable
Trimpot
Switch
Enable = Open
Disable = Closed
Use a trimpot no more than twice the
calculated value of RLIMIT for best resolution.
Thermistors are Negative Temperature
Coefficient (NTC) sensors. Thermistor
resistance decreases as temperature
increases.
RTDs and IC Sensors are Positive
Temperature Coefficient (PTC) sensors.
A PTC sensor’s resistance increases
with increasing temperature.
15
16
Fixed,
Metal Film
OR
R +
R -
Adjustable
(200 k
Ω
typical)
BIAS
BIAS
Use a trimpot no more than twice
the calculated value of R
BIAS
for best resolution.
R
BIAS
determines the bias
current sourced to the sensor
attached at pins 13 & 14. The
chart indicates recommended
currents for typical sensors.
When using a voltage feedback
sensor (such as an AD590),
leave pins 15 & 16 open.
1
Output Current Bias - Pins 2 & 3
Limit Output Current - Pins 1 & 2
Sensor Bias Current - Pins 15 & 16
Sensor - Pins 13 & 14
3
4
OPERATION WITH THERMOELECTRICS
Virtually any type of temperature sensor
can be used with the HTC. It must
produce a feedback voltage between
0.25 V and (V+ minus 1.3 V). See
Step #3 (R
BIAS
) to set the bias current
to the sensor.
I
BIAS
10 mA
1 mA
100
µ
A
10
µ
A
R
BIAS
0
Ω
1.1 k
Ω
12.1 k
Ω
122 k
Ω
100
µ
A
X
+8 V
minimum
AD590
THERMISTOR,
RTD, or LM335
OR
10 kΩ
Sensor -
Indicated resistor values will set I
LIMIT
within
±
5% of indicated value.
If greater accuracy is required for I
LIMIT
, refer to Technical Note
TN-TC07:
Understanding and Improving the Accuracy of the Current
Limit Setpoint on HTC Series Temperature Controllers
.
