Monarch Instrument DC1250 - Manual (Page 15)

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2.3.5 USB Port (Option)
The USB Port is an option and will be installed only if specifically ordered. It is a serial
connection to a PC that allows the user to program the recorder remotely, start or stop
recording and download real time data.
2.3.6 ETHERNET Port (Option)
The Ethernet Port is an option and will be installed only if specifically ordered. It allows
the user to program the recorder remotely, start or stop recording and download real
time data. The IP address is set in the COMMS section in the
Advanced SETUP Menu .
Refer to
Section 5.2 for detailed instructions on the Ethernet interface option.
2.3.7 Isolated DC input (Option)
The unit may be powered by an external DC source with the isolated DC to DC option.
Connect the unit to the external DC source and observe the voltage and polarity of the
inputs.
In order to fully comply with the CE EMC Directive 89/336/EEC the power cable
should be looped through the ferrite bead provided, close to the terminals.
2.3.8 Cleaning
The unit may be cleaned by wiping with a soft cloth. The front panel and display /
keypad may be wiped with a slightly damp soft cloth containing soapy solution or a mild
detergent. Do not use any lemon based (citric acid) product to clean the display /
keypad. NOTE: THE UNIT IS NOT WATERTIGHT.
2.4 INPUT SCALING
The input to the recorder is often a standard process variable (e.g. voltage) rather than the
actual units being measured (e.g. pressure).
There are a number of custom conversions available in the unit to take care of special
inputs such as thermocouples and RTDs, which need special scaling and linearization.
These are preset in the unit and require no modification. There is also the capability to
customize any input variable that has a linear relationship to the measured variable. The
relationship between the required variable and the input variable must satisfy the equation
for a straight line:
y = mx + b
where y is the output value to be displayed and recorded, x is the input variable (typically
volts or milliamps DC), m is the scale factor (slope of the line) which defines the
relationship between the input and the displayed variable and is a constant (linear
relationship), and the factor b (known as the y intercept) is a constant offset variable that
may be positive or negative.
This facility to scale the input is found in the
ADVANCED SETUP menu and is available to
each channel independently. Here the user can easily scale the input and set the displayed
units using three alphanumeric characters.
The scaling is achieved in the unit in the CHANnel X SETUP option (X = A or B) in the
ADVanced SETUP menu. First set the displayed LO SCALE, which may be positive,
negative or zero. Then set the displayed HI SCALE for the full-scale input. The unit will then
automatically compute the scale factor and offset.
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