Section 4 - Monitored Parameters; Introduction; Analog Readings - Pentair 920 Series Installation, Operating And Maintenance Instructions

seCtIon 4 – monItored parameters

4.1 IntroduCtIon

4.2 anaLoG readInGs

INDUSTRIAL HEAT TRACING SOLUTIONS
The following is a brief summary of each of the measured and calculated parameters the 920
series control module provides to the user. Detailed information regarding settings, alarms limits,
etc. may be found in Section 3 on page 18. For detailed information regarding the display of these
variables using the 920 Operator Console, Model 780/GCC-9000, Raychem Supervisor or other
interface, refer to the ap-propriate user manuals.
4.2.1 ControL temperature
purpose: This is the temperature the controller uses to determine whether its output switch
should be on or off. Depending on the TS CONTROL MODE setting, whether one or two RTDs are
installed, and TEMPBUS™ is being used, the CONTROL TEMPERATURE may be derived from TS
1, TS 2, TEMPBUS™ or a combination of the three temperatures. See section 3.5.12 on page 24 of
this manual for further details regarding the TS CONTROL MODE settings.
4.2.2 ts 1 temperature
purpose: This temperature is the value the controller reads from the RTD connected to its
TS 1 input. Depending on the TS CONTROL MODE, it may be used to determine the CONTROL
TEMPERATURE (see section 4.2.1 on page 47).
Important: (V3.11 and up): If the TS 1 input is not being used by the controller, the TS 1
TEMPERATURE is not displayed.
Important: Changing the TS Type will affect the temperature reading.
4.2.3 ts 2 temperature
purpose: This temperature is the value that the controller is reading from the RTD connected to
its TS 2 input. Depending on the TS CONTROL MODE, it may be used to determine the CONTROL
TEMPERATURE (see section 4.2.1 on page 47).
Important: (V3.11 and up): If the TS 2 input is not being used by the controller, the TS 2
TEMPERATURE is not displayed.
Important: Changing the TS Type will affect the temperature reading.
4.2.4 Load Current
purpose: The LOAD CURRENT reading indicates the average current being drawn by the heating
cable.
Important: The controller calculates the LOAD CURRENT using the current sensed by the switch
interface module multiplied by the CURRENT TURNS RATIO to yield an adjusted current value.
4.2.5 resIstanCe
purpose: Resistance is calculated using the average adjusted voltage reading divided by the
average adjusted current reading to yield a load resistance in ohms. If the controller's output
switch is on but no current is present, the RESISTANCE will read "open circuit."
Important: If the controller's output switch is off, the RESISTANCE will display the last
resistance which was calculated while the output switch was on.
4.2.6 Ground fauLt Current
purpose: If the controller detects any leakage current in the output circuit, it will indicate the level
in milliamps.
Important: To minimize nuisance alarms, the controller will not report a leakage current of less
than 20 mAmps.
4.2.7 voLtaGe
purpose: The voltage reading indicates the average circuit voltage being measured by the switch
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