56
ing on the temperature and the lead resistance. See Appendix D on page 74 or Appendix E on
page 75.
• Verify that the
RTD is wired correctly. The heat-tracing controllers will always be terminated
in the order: source (
WHT), sense (WHT), common (RED). When using the terminal board,
these terminals are marked as follows:
The
RTD manufacturer will typically color code the leads with the source and sense being the
same color, and the common a different color. Ensure that the
RTD extension wire shield is ter-
minated at one end only, normally using the terminal block provided at the terminal board.
Note: Some
RTDs may have the Sense wire color coded as Black.
2. Questionable Temperature
If you feel that the indicated or displayed temperature is not correct, the controller and the
RTD
can be quickly checked for correct operation.
To verify the
RTD:
Turn off the power to the controller before proceeding!
• Disconnect the
RTD wiring from the input terminals.
• To calculate the temperature indicated by the
RTD, measure the resistance from source (white
wire) or sense (white wire) to common (red wire) and subtract the resistance measured
between source and sense. This will give a compensated resistance value that can be cross-
referenced to the
RTD table, DIN Standard 43760 found in Appendix D on page 74 or Appen-
dix E on page 75. Compare the measured resistance and cross-referenced temperature value
obtained from the
RTD table to the indicated or displayed value. These should agree to within
the accuracy standards of the
HTC and the RTD.
To verify the Controller:
Turn off the power to the controller before proceeding!
• Disconnect the
RTD wiring from the input terminals.
• Connect a 100 Ω resistor across the source or sense terminal and common. Insert a jumper
between the source and sense terminals.
• Apply power to the controller. The indicated or displayed temperature should be about 0°C
(32°F) depending on the actual resistance of the test resistor if
TS TYPE is set to 100 Ω Platinum.
3. Unstable or Bouncing Temperature
An erratic indication of temperature can be caused by several factors external to the controller;
however, a bouncing temperature of a few degrees should not be confused with incorrect opera-
Terminal No. Description
25 Point A, Shield
26 Point A, TS 1 Source (
WHT)
27 Point A, TS 1 Sense (
WHT)
28 Point A, TS 1 Common (RED)
9 Point A, Shield
10 Point A, TS 2 Source (
WHT)
11 Point A, TS 2 Sense (WHT)
12 Point A, TS 2 Common (
RED)
29 Point B, Shield
30 Point B, TS 1 Source (
WHT)
31 Point B, TS 1 Sense (
WHT)
32 Point B, TS 1 Common (
RED)
13 Point B, Shield
14 Point B, TS 2 Source (
WHT)
15 Point B, TS 2 Sense (
WHT)
16 Point B, TS 2 Common (
RED)
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