TC to RTD
TC to RTD
(OP)
We are using A Watlow D-8 to control 8 heaters. The D-8 uses 100ohm RTD inputs for control. During final assembly of the the prototype, we discovered 2 of the heater only have TCs.
Does anybody know of a way to convert a TC to RTD signal or if it is even possible?
Thanks in advance
js
Does anybody know of a way to convert a TC to RTD signal or if it is even possible?
Thanks in advance
js





RE: TC to RTD
http
I didn't see an RTD output, but I didn't check carefully...
RE: TC to RTD
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: TC to RTD
From the D8 spec sheet at:
http:
Analog Inputs
• Thermocouples: User selectable type, direct connection,
linearization, reference junction compensation, reversed
and shorted T/C detection and upscale break protection
with output averaging.
• RTD: 2 or 3 wire, platinum, 100? @ 0°C, DIN curve.
Requires scaling resistors. See special inputs in ordering
information.
• Linear: current and voltage signals from linear transmitter
Input Range and Accuracy
Sensor Range (°C) Range (°F) Accuracy
Type B 66 to 1760°C 150 to 3200°F ±4.0°C
Type E -200 to 787°C -328 to 1448°F ±1.0°C
Type J -212 to 760°C -350 to 1400°F ±1.2°C
Type K -268 to 1371°C -450 to 2500°F ±1.3°C
Type R -18 to 1766°C 0 to 3210°F ±2.8°C
Type S -18 to 1760°C 0 to 3200°F ±2.8°C
Type T -268 to 399°C -450 to 750°F ±1.6°C
RTD -200.0 to 621.1°C -328.0 to 1150.0°F ±0.5°C
I don't have time to dig out the specifics, but there's some means of configuring it to take a thermocouple.
Do you know what type thermocouple you are working with?
Dan
RE: TC to RTD
Apparently, the Watlow does not have an universal input circuit. I am sure that they have a reason, but I can't imagine why.
I would recommend installing 2 RTDs in your heaters, and keeping all of the Watlow channels identical. Otherwise, somebody will mix up the channels some day.
RE: TC to RTD
Pages 190 to 193 (pdf) of the D8 manual describe the input scaling resistors for field changes. Thermocouples use a "0 ohm resistor".
Page 149 (pdf) shows the configuration selection for TC type.
manual at:
http:/
Dan
RE: TC to RTD
RE: TC to RTD
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com