Watlow Series L
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Chapter 1: Over view
Series LF and LV
Watlow's temperature limit controllers
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provide an
economical limit controller solution for applications
where thermal system protection is needed.
A limit controller is added to applications to prevent
over or under temperature conditions. The limit pro-
vides safety assurances against instances where a
thermal runaway condition occurs as a result of a
failed sensor, controller or output device.
The LF and LV limit controllers are recommended for
any application where thermal system runaway could
result in large product scrap costs, damage to system
equipment, potential fire hazard or risk to personnel.
Both controllers are Factory Mutual and CSA ap-
proved.
The LF and LV controllers are available with or with-
out an operator interface and can be ordered in square
1/8th DIN panel mount, din rail mount, open board or
potted module design configurations. Push-on, quick
connect spade terminal or removable screw clamp style
terminal block ordering options provide the electrical
connections.
The microprocessor design platform provides improve-
ments in the performance, repeatability, and accuracy
offered by Watlow's current line of basic control prod-
ucts.
The Series LV includes an operator interface to allow
viewing and selection of the limit set point. A red four
character, seven-segment LED displays the limit set
point. The limit set point selection is made with a con-
tinuous turn, velocity-sensitive rotary encoder. Push-to-
Set operation reduces accidental limit set point adjust-
ments. Limit set point operating range temperature
values are customer definable in the product configu-
ration part number.
The Series LF offers fixed limit set points. These units
are supplied without an operator interface. Limit set
point temperature values are customer definable in
the product configuration part number.
The features and performance of the LF and LV con-
trollers make them ideally suited for a wide range of
industrial limit control applications in the food prepa-
ration, industrial machinery, packaging and plastic
markets.
Series LS
This control meets the newest safety standard require-
ments for the food service industry UL/EN 60335
equipment. It is approved to UL/EN 60730-1 and
60730-2-9 Electronic Control Thermal Cut-out Class
II with Class B Software review. It provides increased
safety due to the use of Factory fixed set point, Factory
fixed hysteresis and the use of redundant tempera-
ture sensors to protect against a single point sensor
failure. Either sensor can initiate an over temperature
limit condition along with a deviation between sensors
greater than the process comparison value. The unit
cannot be reset until both sensors are below the Limit
Temperature minus the hysteresis value. A power cycle
is then needed to reset the control.
Definitions under UL/EN 60730-1 , 60730-2-9
Protective
- Intended to provide safety or protective
functionality. A control the operation of which is in-
tended to prevent a hazardous situation during abnor-
mal operation of the equipment
Type 2 Action
- Calibration Verification Testing or
Functionality Verification testing conducted.
A Type ".B"
control has been investigated for "micro-
disconnection" applications. Disconnection of any pole
(ungrounded conductor is not specified) for functional
purposes.
A Type ".K"
control is designed that in the event
of a break in the SENSING ELEMENT, or in any
other part between the SENSING ELEMENT and
the SWITCH HEAD, the declared disconnection is
provided before the declared OPERATING VALUE ,
OPERATING TIME or OPERATING SEQUENCE is
exceeded.
THERMAL CUT-OUT
- UL60730 Par 2.2.8. A Tem-
perature Cut-out in accordance with UL60730 is de-
fined as temperature sensing control intended to keep
a temperature below or above one particular value
during abnormal operating conditions and which has
no provision for setting by the user. A UL60730 THER-
MAL CUT-OUT is similar to a UL873 Temperature
Limiting control.
Class B
- software that includes code intended to pre-
vent unsafe state in appliance.
All Watlow Series L limit controllers include industry-
leading service, support and a 3-year warranty.
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Also available, Series C, an on-off temperature con-
troller version.
Overview
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