Pentair 920 Series Installation, Operating And Maintenance Instructions page 54

INDUSTRIAL HEAT TRACING SOLUTIONS
• 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:
terminal no.
25
26
27
28
9
10
11
12
29
30
31
32
13
14
15
16
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
terminated at one end only, normally using the terminal block provided at the terminal board.
Important: 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 Appendix
E on page 75. Compare the meas-ured 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
operation. The controller's accuracy and resolution will result in an indicated temperature
change of a couple of degrees if the measured resistance temperature falls between two
discrete values. This is sometimes referred to as quantization error.
EN- Raychem920series-IM-H56874 05/15
description
Point A, Shield
Point A, TS 1 Source (WHT)
Point A, TS 1 Sense (WHT)
Point A, TS 1 Common (RED)
Point A, Shield
Point A, TS 2 Source (WHT)
Point A, TS 2 Sense (WHT)
Point A, TS 2 Common (RED)
Point B, Shield
Point B, TS 1 Source (WHT)
Point B, TS 1 Sense (WHT)
Point B, TS 1 Common (RED)
Point B, Shield
Point B, TS 2 Source (WHT)
Point B, TS 2 Sense (WHT)
Point B, TS 2 Common (RED)
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