Parr Instrument 4848B - Manual (Page 17)

4848B Reactor Controller
w w w . p a r r i n s t . c o m 15
Motor Control Module (MCM)
RPM
When this optional module is present, the left dis-
play in red shows the stirring speed, and the right
hand display in green shows the rpm setpoint. The
4848B Controller is designed to run in either Local
or Remote stirring mode. The local/remote switch
on the front panel will toggle between these two
modes.
In Local mode, the stirring speed is controlled by
turning the speed control knob on the front panel.
The rpm setpoint has no bearing on the stirring
speed.
In Remote mode, the motor will stir at the rpm set-
point using closed loop PI control. The speed con-
trol knob has no bearing on the stirring speed.
The RPM setpoint may be adjusted by doing the fol-
lowing:
1. Press the up or down arrow until the lower
display shows the desired setpoint. The lower
display will blink, showing the value has not
been set yet
2. Press the set button. The lower display will stop
blinking, showing the new value has been set.
Motor Torque Module (MTM)
This module provides a means for continuously
monitoring the motor output percent to the stirrer
motor. When used with a Motor Control Module
(MCM), the motor speed control will provide a con-
stant stirring speed at a given setting. Changes in
the power required by the motor will correspond to
changes in the viscosity of the fl uids in the vessel.
This will be a useful option for users who want to
monitor the progress of a polymerization reaction
in which there are viscosity changes as the reaction
proceeds.
High-Temp Cut-Off Module (HTM)
TEMPERATURE
This module provides a redundant high tempera-
ture safety cut-off which will shut down the reactor
heater if an unusual malfunction should develop in
the primary control system. It is a completely inde-
pendent safety backup system, operating in addition
to the high-limit control built into each Parr tempera-
ture controller. It has its own thermocouple, digital
display and wiring, and can be preset to shut down
the heater at any desired temperature.
If the secondary temperature (PV) exceeds the alarm
setpoint (SV), the alarm indicator on this display will
illuminate and the High Limit breaker will trip, inter-
rupting power to the heater.
The High Temp Cut-Off Alarm setpoint may be ad-
justed by doing the following:
1. Press the up or down arrow until the lower
display shows the desired setpoint. The lower
display will blink, showing the value has not
been set yet.
2. Press the set button. The lower display will stop
blinking, showing the new value has been set.
This secondary temperature module does not con-
trol the heater. It is used as an alarm only.
When ordering this option separately or installed in
the 4848B Parr Controller, always specify the reactor
with which it will be used so that a thermocouple of
the proper style and length can be furnished.