4. Design and function
4. Design and function
4.1 Overview of the different instrument models
CTD4000-140 (cooling and heating)
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CTD4000-375 (heating)
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CTD4000-650 (heating)
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The temperature dry-well calibrator consists of a robust,
grey-painted steel case, with a carrying handle on top.
The rear part of the case contains a metal block with a
19 x 150 mm or 26 x 150 mm bore in which the inserts can
be placed.
With the help of the inserts temperature probes of different
sizes can then be calibrated.
The heater element heats the block and an electronic µ
controller with static relay output checks and regulates the
temperature.
The metal block is thermally insulated.
A centrally mounted fan generates a constant air flow that
reduces the temperature of the case.
The air flow is divided in two parts: One part of the air flows
from the back of the calibrator, while the second part of the
flow is parallel to the top grid of the calibrator. Thus, the
stem of the sensor is above the insert at the lowest possible
temperature.
The front part of the case contains the complete electronic
unit for controlling the reference temperature.
To control the heating elements, solid-state relays (SSRs) are
used.
On the front panel is the controller, which is fitted with an LED
display (2-line) for the reference and set temperature.
The calibrator is fitted with the following
protective devices to prevent hazards in
operation.
Temperature controller that recognises any
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possible break in the temperature sensor and
disconnects the heating
Maximum temperature safety thermostat to
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disconnect the heating system
Protective grille to prevent any contact with
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the metal block
Protective fuses
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WIKA operating instructions, model CTD4000
4.2 Isometric views
Front and top
On the top of the temperature dry-well calibrator, you will find
the dry well access opening for inserting the insert.
The controller, with display and controls, is located on the
front of the calibrator.
The temperature switch test is found through the indicator.
In the lower area are the mains connector socket and the
power switch with its fuse holder.
Furthermore, the mains voltage and the fuse rating is given.
On the right hand side, next to the power connection is
located the RS-232 interface.
Rear of the instrument
On the rear of the case are located the product label and the
fan.
This must not be obstructed in any way!
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Temperature block with insert
Fan
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Product label
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RS-232 interface
4
Mains connector socket with power switch and fuse
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Temperature controller
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Temperature switch test
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Carrying handle, retractable
EN
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