4 8 4 8 R e a c t o r C o n t r o l l e r
P a r r I n s t r u m e n t C o m p a n y
4
reflects the degree of loading on
the motor in order to maintain
a constant stirring speed. While
not a direct torque measure-
ment, this is a useful option for
those who want to, for example,
monitor the progress of polymer-
ization reactions in which there
is a change in viscosity as the
reaction proceeds. The output to
the motor can be displayed on
the PC, but to log this value re-
quires the addition of the Motor
Torque Module.
4A. High Temperature Cut
Off Module (HTM)
The high temperature cut off
module or limit controller aug-
ments the operation of the main
control module. Its redundant
sensor can be mounted either
internally or externally to the
reactor. The primary output of
the module is wired to activate
the lock out relay in order to
provide safety shutdown should
the reactor reach an unsafe tem-
perature.
4B. External Temperature
Limit Module (ETLM)
This configuration uses the
same aforementioned HTM
Module with its sensor mounted
in such a way to monitor the
reactor’s outside wall tem-
perature. The primary output
of this module is used to limit
the external temperature of the
reactor. This is done
by interrupting the
control signal form
the main temperature
controller when the
external temperature
exceeds a predeter-
mined value. The
secondary output of
this module is used to
activate the lock out
relay if the outside
wall temperature ex-
ceeds a preset unsafe
temperature. The use
of this module pro-
vides and effective
alternative to cascade
control, offering im-
proved temperature
regulation in systems
with large thermal
lags, such as those found in
non-stirred reactors or systems
that use PTFE liners, as well as
systems where the reactants
have low heat capacities, such
as gas phase reactions.
5. Motor Torque Module
(MTM)
Parr furnishes permanent
magnet DC stirrer motors for its
magnetic drives in which there
is a linear relationship between
torque and applied voltage for a
fixed RPM. This module provides
a means for continuously dis-
playing and logging the voltage
supplied to the stirrer motor.
This voltage is displayed as a
percent of full span. This module
must be installed in conjunction
with the Motor Control Module.
4848 back panel for 115V model.
