Adjustments
97
Replacement of the TH 43 board:
once the TH 43 board has been replaced, it is necessary to perform the above adjustments, to
avoid errors due to the tolerance of any component in the furnace.
4.10.2 Furnace regulation board TH 43 / TH 44
Description of its function:
Fig. 79: Furnace regulation board TH 43/TH 44
The TH 43 or TH 44 control board regulates the furnace power, first by comparing the
temperature set point with the actual furnace temperature, then by sending the appropriate
signal to the thyristor drive unit.
The output voltage of the thermocouple (actual furnace temperature) can be read at TP1. Its
range is about 13 mV at 1300°C.
The output voltage versus temperature characteristic of a thermocouple is not perfectly linear. A
linearisation unit therefore, has been included in the above circuit.
Once linearized and amplified, the furnace temperature voltage can be read on TP10. The
temperature set point, which is adjustable with the potentiometer on the furnace, is compared
with the actual furnace temperature voltage.
The resultant voltage (on TP12) is then fed to the thyristor drive unit, thus increasing or
decreasing the furnace voltage.
A current limitation circuit keeps the furnace current within safe limits.
Either the temperature set point or the actual temperature can be digitally displayed, depending
on the switch setting on the furnace.
NTC
TP10
TP5
TP2
TP7
+15V
+5V
-5V
Temp.compensation
TP12
TP3
+15V
+15V
F u r n a c e
temperature
d i s p l a y
Mains L
Mains N
TP6
TP1
TP4
Linearisation
J 2 / 1
J 2 / 2
J 2 / 5
J 2 / 1 3
J 2 / 4
J 2 / 9
J 2 / 1 0
T E M P E R A T U R E S E T P O I N T
ACTUAL TEMPERATURE VALUE
2-6-3
l i m i t a t i o n
C u r r e n t
J 5 / 5
J 5 / 6
J 5 / 9
J 5 / 8
e l e m e n t s
H e a t e r
T h y r i s t o r
d r i v e
F u r n a c e
temperature
s e t t i n g
max.
setpoint
Thermocouple
Содержание CS-2000
Страница 2: ...2 Copyright Copyright by Eltra GmbH Retsch Allee 1 5 D 42781 Haan Germany ...
Страница 6: ...Notes on service instructions 6 ...
Страница 72: ...Adjustments 72 Fig 57 Gas flow regulation The flow controller mainly consists of the following components ...
Страница 77: ...Adjustments 77 Fig 61 IRC 1 3 ...
Страница 107: ...Service 107 Fig 91 Tubes to squeeze ...
Страница 120: ...Miscellaneous 120 6 1 2 Left hand side Fig 106 Left hand side view ...
Страница 122: ...Miscellaneous 122 6 1 3 Right hand side Fig 107 Right hand side view ...
Страница 129: ...Miscellaneous 129 6 1 7 Infrared cell Fig 111 Infrared cell ...
Страница 139: ...Miscellaneous 139 Fig 119 Left hand side power wiring 6 2 3 Valve wiring ...
Страница 140: ...Miscellaneous 140 Fig 120 Valve wiring 6 2 4 Control signal wiring Fig 121 Control signal wiring ...
Страница 142: ...Miscellaneous 142 6 2 6 IR cell internal signals Fig 123 IR current supply new version ...
Страница 145: ...Miscellaneous 145 6 3 2 Gas flow for induction furnace when furnace is open ...
Страница 146: ...Miscellaneous 146 6 3 3 Gas flow for resistance furnace ...
Страница 147: ...Miscellaneous 147 6 3 4 Valve contolling ...
Страница 160: ...Copyright Copyright by Eltra GmbH Retsch Allee 1 5 D 42781 Haan Germany ...