Liebert CHALLENGER 3000 - Manual (Page 34)

Operation with Advanced Microprocessor with Graphics Control
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3.11 Analog/Digital Inputs
Selecting ANALOG/DIGITAL INPUTS steps to the following menu:
• READ ANALOG INPUTS
• SETUP ANALOG INPUTS
• READ DIGITAL INPUTS
• SETUP DIGITAL INPUTS
3.11.1 Read Analog Inputs
The four (4) analog sensor inputs can be monitored from the display. The inputs are filtered, then dis-
played along with the text label assigned during setup.
3.11.2 Setup Analog Inputs
For installation of analog sensors, see Analog Setup on page 11.
After selecting a compatible sensor and properly wiring it to the terminals, set the control to monitor
the sensor according to the following instructions.
Slope
The slope is a multiplier used to scale the input signal. The slope can be positive (rising) or negative
(falling) and can range from 0 (resulting in a horizontal line) to ±999. The slope for a 0-5 volt input is
per 1 volt input; for 0-10 volt input, it is per 2 volt input; and for 4-20 mA, it is per 4 mA input. For
example, assuming an intercept of 0, for a 0-10 volt sensor input with a slope of 50, an input of 1 volt
would be displayed as 25: 1x(50/2); 2 volts would be 50: 2x(50/2); 3 volts would be 75: 3x(50/2); etc.
Intercept
The intercept is an offset from point 0 corresponding to 0 volts or 0 mA input. The intercept can be
positive or negative and can be a point from 0 to ±999. Adding an intercept of 100 to the slope example
above, 1 volt would be 125: 100 + (1x[50/2]); 2 volts would be 150: 100 + (2x[50/2]); 3 volts would be
175: 100 + (3x[50/2]); etc.
Text
You may enter a custom label for each analog input. The text label can be 20 characters in length
including any of the following:
ABCDEFGHIJKLMNOPQRSTUVWXYZ#%*-0123456789, or space.
3.11.3 Read Digital Inputs
The four custom alarm inputs can be defined to be digital inputs. Digital inputs are used to sense cus-
tomer devices for status display purposes only and will not activate the audible alarm.
3.11.4 Setup Digital Inputs
A digital input is enabled by defining one of the four custom alarms to be STATUS ONLY type in the
alarm setup screen. The digital input is given a name by specifying it to be one of the optional alarms
or a custom text alarm. See 3.4.3 - Setup Alarms and 3.4.4 - Setup Custom Alarms.
3.12 View Run Hours Log
Selecting VIEW RUN HOURS LOG will step to the following menu:
• VIEW 24 HOUR RUN TIME HISTORY
• VIEW TOTAL RUN HOURS
NOTE
For a 4-20 mA input sensor, if the desired reading at 4 mA input is 0, then an intercept
of -1 x slope would be required. For example, assuming a slope of 50, the formula would
be ([-1 x 50] + 4 x [50/4]) = 0. The intercept is -50.