West Control Solutions MRC 8000 - Manual (Page 40)

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Dual Pen Instruments: If the instrument is specified and provided with the Remote Setpoint
capability for either or both pens and the Remote Setpoint has been properly configured in the
Program mode for either or both pens, the Setpoint Select mode will be accessible, if enabled.
Press and release the SCROLL keys until SPS appears in the display, then press the DOWN
key. The left display will light and the upper display will blank if pen 1 is selected for a remote
setpoint. If only pen 2 is selected as a remote setpoint, then the left display will blank and the
right display will light. If both pens are selected for remote setpoint, the right display is
accessed by pressing the DOWN key while the left display shows the setpoint mode selected
for that pen. The display(s) will show Loc if the local (keypad entered) setpoint is being used
or rSP if the remote setpoint is in use. Press the SCROLL key to select the setpoint mode that
will be used by the instrument. Press the UP key to exit the Setpoint Select mode. If a
problem develops with the remote setpoint signal for either pen, the left display will show rSEr,
the remote setpoint error code.
Digital Communications: The setpoint can be adjusted from a supervisory computer system.
Dual pen instruments are capable of having independent setpoint adjustments for each pen.
SETPOINT SELECT FLOW CHART (APPLIES TO RECORDING CONTROLLERS)
4.1.2.3 ON-OFF CONTROL
On-Off control can only be implemented on controllers provided with SPST relay or SSR driver
output's. On-Off operation can be assigned to either or both output 1 and 2 for each pen. The
On-Off control can be selected as direct or reverse acting. Direct action is typically used in
cooling applications. The output device will turn On when the process value is greater than the
setpoint. Reverse action is typically a heating application. The output device will turn On if the
process value is below the setpoint. A hysteresis adjustment is provided for On-Off outputs on
each pen. This adjustment is in terms of degrees/engineering units and defines the width of
the hysteresis band about the setpoint. This parameter may also be referred to as a
deadband. Relay chatter can be eliminated by proper adjustment of this parameter. When
operating in On-Off control, the control algorithm will turn the output On or Off depending upon
the setpoint, the relative position of the process value, and the hysteresis adjustment. The
respective OUT1 or OUT2 indicator for the respective pen will illuminate to indicate that the
output device is On.
rSP
LOC
SPS
ON
OFF
Actual Display
On/Off Display -
Use arrow keys
to turn on or off
Scroll Key
Numeric Display -
Use arrow keys
to change value
Up Arrow Key
Down Arrow
KEY