Carbolite TVS Series - Manual (Page 5)

HZS, TVS
MF24 – 3.44
5
3.0 O PERATION
The instructions for operating the temperature controller are given in a separate manual.
If the furnace is fitted with a time switch, see also the supplementary manual MS03.
If cascade control is fitted, see the supplementary manual MS07.
3.1 3-zone Control Methods
The models in this manual are typically designed to achieve an extended uniform temperature zone
by the use of three control zones, with he control zones linked so that end zones follow the central
zone in a master-slave approach; there are two ways of doing this. Alternatively, independent
control zones may be ordered. There are thus three control methods (A, B & C).
A. Back-to-Back Thermocouples
This is the most commonly supplied option.
The central zone of the work tube is controlled directly by the central temperature controller. Each
end zone thermocouple is wired in opposition to a central reference thermocouple, and the
resulting small voltage difference when the zones are at different temperatures is used by the end
zone controller. The circuit diagram in section 7.0 shows the thermocouple arrangement.
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
MUST NOT exceed the furnace maximum temperature.
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 – this may depend on the
customer work load. The end controllers strive to remain at the central temperature, and prevent
cooling. Should this occur, please contact Carbolite’s technical department.
2132 Slave Controller Navigation Diagram
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.
It is possible to switch off the linked control and allow the controllers to work independently. In
level 2 of the end zone controllers (see controller operating instruction), scroll to
L-r. Where the
end zone controller is a 3216 use the  up  down and select NO . Where the end zone controller
Home
List
Access
List
°C/F/k ACCS
°C/F/k codE
0.0
Zone temperature
difference; use

/

to
access offset “setpoint”
home list
for factory access to lists
and parameters not
available to the operator


OP.Hi
Output
List
oP

power limit
setting, if
present