Super Systems 9120 RPSC - Manual (Page 5)

Model 9120 Redundant Probe System - Color
4580 – Redundant Probe System – Color Page 5 of 23
About the Model 9120 – RPS
The Model 9120-RPS is specifically designed to read two SSi Gold Probes, installed in the same furnace.
The Model 9120-RPS controller, a 24 VDC power supply, and two 24 VDC relays are mounted and wired on
a piece of DIN rail for easy mounting. Two other components included with the Model 9120-RPS are the
operator interface and the cable connecting the operator interface to the Model 9120-RPS.
Electrical Installation
The Model 9120-RPS comes mounted on a DIN rail, pre-wired and tested. AC power needs to be connected
to the 24VDC power supply. See the section
Typical Electrical Drawing for other required connections.
Model 9120-RPS Function
The Model 9120-RPS reads a signal from each of the two oxygen probes located in the furnace. Depending
on the 9120-RPS configuration, it will select whichever millivolt reading it has been configured (high or low)
to select and retransmit this millivolt output to the atmosphere controller.
The probe millivolt deviation band and the alarm delay times are set using the operator interface. See the
section
Menu Screens and Chart Screen for more information on how to use the operator interface. When
connected per the electrical drawing (section Typical Electrical Drawing ), the Model 9120-RPS default
configuration is set to retransmit the millivolt signal from the probe with the highest millivolt output. As
time passes and if/when the other probe’s millivolt output becomes greater (dependent on the deviation
band), the Model 9120-RPS will switch the output from one probe to the other and send the “new” higher
(or lower, depending on the configuration) millivolt signal to the atmosphere controller. The deviation band
must be exceeded for the retransmit to occur.
The black millivolt value on the operator interface display indicates which probe’s millivolts are being used
by the furnace atmosphere controller.
The operator can manually select the probe that is to be used in the carbon calculation. If this feature is
used, the 9120-RPS will use the operator-selected probe, and NOT switch from one probe to the other
automatically. See the section
Menu Screens – Redundant Probe Setup for more information on how to
manually select a probe.
The deviation alarm is disabled if both probes’ millivolts drop below 950. This should eliminate the nuisance
alarm when the furnace is loaded and the temperature drops.