beautypg.com

West Control Solutions MRC 7000 Controller Manual User Manual

Page 38

background image

38

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 upper display will light and the lower display will blank if pen 1 is selected for a
remote setpoint. If only pen 2 is selected as a remote setpoint, then the upper display will
blank and the lower display will light. If both pens are selected for remote setpoint, the lower
display is accessed by pressing the DOWN key while the upper 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 upper 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

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