Carbolite GHA Installation, Operation & Maintenance Instructions Manual page 8

G range
Set the "setpoint" of the end zone controllers to zero. Alternatively, a small temperature difference
(offset) can be created by setting a non-zero value, but the sum of the main controller set-point and
the slave controller offset
temperature" display shows the actual offset.
To alter the setpoint (with the display at "home"), press Down  or Up  once to display the
setpoint; press again or hold down to adjust it. The display returns to the measured temperature
offset when no key is pressed for 0.5 seconds.
Sometimes a furnace using this type of control does not cool down: the end controllers try to
remain at the current central temperature. Should this occur, contact Carbolite's technical
department.
2132 Slave Controller Navigation Diagram
Home
List

0.0

°C/F/k
Zone temperature
difference; use
access offset "setpoint"
B. Retransmission of Setpoint Using Broadcast Comms
When this is ordered there are three independent thermocouples connected to the three controllers.
The controllers are linked together, the central controller communicating the desired setpoint to the
end controllers.
Additional communication modules are fitted in the controllers, rather than an additional
thermocouple as in A. The communication between the controllers of the Eurotherm 3000 series is
known as Broadcast comms. The wiring connections between the controllers are shown in section
7.8
It is possible to switch off the linked control and allow the controllers to work independently. In
level 2 of the end zone controller (see controller operating instruction), scroll to
 up  down and select NO. The is no need to alter the centre controller.
It is possible to use local trim in the end zone controllers to enter a positive or negative adjustment
from the centre zone temperature. Once entered this trim will always be added or subtracted from
the retransmitted set temperature. In level 2 of the end zone controller (see controller operating
instruction), scroll to
negative difference to be added to the end zone set temperature. There is no need to alter the
centre controller.
C. Independent Control
In this case the three controllers are completely independent. Remember that it is not possible to
maintain very different zone temperatures because of heat transfer within the furnace body and
work tube.
3.3 General Operating Advice
Heating element life is shortened by use at temperatures close to maximum. Do not leave the
furnace at high temperature when not required. The maximum temperature is shown on the rating
label and on the back page of this manual.
Light weight ceramic fibre insulation can easily be marked by accidental contact. Some fine cracks
may be visible on the surface of the insulation, or may develop in the surface of the chamber due
8
exceed the furnace maximum temperature. The "measured
MUST NOT
Output
°C/F/k

OP.Hi
 
/ to
power limit
setting, if
present
(local trim) and use the  up  down enter the desired positive or
LOC.T
Access
List
List
ACCS
oP
codE
home list
for factory access to lists
and parameters not
available to the operator
L-r
and use the
MF48 -1.18