24
Setting: OFF or ON
Procedure: If the HTC should turn the output switch off when it cannot read a valid control tem-
perature, then select
OFF; otherwise, if the output switch should turn on, then select ON.
Note: This parameter is part of the
TS CONTROL MODE.
3.5.12 TEMPERATURE SENSOR CONTROL MODE
Purpose: The
TS CONTROL MODE allows the selection of one of eleven possible temperature con-
trol modes for the controller. The different modes allow redundant fail-safe temperature sensing,
averaging, or minimum maintain temperature control.
Setting: Select one of the following eleven possible modes:
Control TS and Description
CONTROL USING TS 1, FAIL OFF/ON
CONTROL USING TS 1, FAIL TO TS 2
CONTROL USING TS 2, FAIL OFF/ON
CONTROL USING TS 2, FAIL TO TS 1
CONTROL ON AVERAGE, FAIL OFF/ON
CONTROL ON AVERAGE, FAIL TO GOOD
CONTROL ON LOWEST, FAIL OFF/ON
CONTROL ON LOWEST, FAIL TO GOOD
The following are only available in V3.11+:
CONTROL USING EXT. INPUT, FAIL OFF/ON
CONTROL USING EXT. INPUT, FAIL TO TS 1
CONTROL USING EXT. INPUT, FAIL TO TS 2
Where OFF/ON = Controller’s output switch turned OFF or ON as determined by the TS FAIL MODE.
Example: With a TS CONTROL MODE of CONTROL ON AVERAGE, FAIL TO GOOD, the controller will
measure both sensors (
TS 1 and TS 2), averaging the two temperature value;, display the results;
and cycle the heater
ON or OFF to maintain the CONTROL SETPOINT temperature. This is the pri-
mary control mode. If either sensor should fail, the controller will transfer control to the remain-
ing “good” sensor and generate the appropriate
TS 1 or TS 2 FAILURE ALARM (assuming that the
alarm is enabled). The temperature will now be maintained based on this measured value. If the
remaining good sensor fails, the controller will turn the heater
OFF or ON as determined by the TS
FAIL MODE
setting. The appropriate TS 1 or TS 2 FAILURE ALARM will be also be generated.
Procedure: Select the control mode that best suits the application.
Notes:
• Ensure that
TS FAILURE ALARMS are enabled. See sections 3.7.1 on page 32, 3.7.4 on
page 32, and 3.7.10 on page 34 for a complete explanation of
RTD failure detection in the
HTC.
• If the selected
TS CONTROL MODE uses the EXTERNAL INPUT then the EXTERNAL INPUT must be
set to
TEMPBUS™ (see Section 3.6.3). Also, the CONTROL TS FAILURE ALARM is non-latching in
this mode.
• Fail safe mode is always disabled if the
TS CONTROL MODE = EXT. INPUT, FAIL OFF/ON.
3.5.13 TS 1 TYPE (V3.11 AND UP)
Purpose: This parameter specifies the type of
RTD that is connected to the HTC’s TS 1 input.
Setting: 3-wire 100 Ω platinum or 2-(or 3-) wire 100 Ω nickel-iron (Ni-Fe)
Procedure: Select the type of RTD that is connected to the TS 1 input.
Note: If a 2-wire 100 Ω nickel-iron (Ni-Fe) RTD is selected then the TS 1 LEAD RESISTANCE must
be entered manually (see section 3.5.14 on page 24).
3.5.14 TS 1 LEAD RESISTANCE (V3.11 AND UP)
(For Ni-Fe
RTDs only)
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