From this point, a count wheel mounted on the lead screw provides positional
information relative to the zero position. There are 32 counts for each division
on the chart paper.
As with all positioning mechanisms, an error may appear in the tracking over a
period of time. To minimize this error, several steps have been taken. First, a
deadband for pen movement of
1
⁄
2
chart division has been programmed in to
minimize pen motion without affecting usable chart resolution. Second,
whenever you change chart paper, a magnetic switch detects the opening of
the door and initiates a system reset, thus re-zeroing the pens and eliminating
any accumulated errors
.
A further unique feature of the recorder is its
ability to utilize charts with either
Fahrenheit or Celsius scales via switch selection on the front panel.
The
microprocessor adjusts the range of travel for the temperature and humidity
pens so that convenient scales for both can be used.
10.3 Chart Paper Drive Mechanism
The recorder incorporates a stepper motor to impart rotational motion to the
chart paper. A novel feature of the unit is its
ability to utilize 1, 7 or 32 day
chart paper simply through front panel switching.
This capability is provided
by a special digital timing circuit which precisely controls the stepping rate of
the magnetic armature in the motor.
10.4 Power Supply Supervision
The recorder contains power supply monitoring and switching circuitry which
enables it to be used in a variety of circumstances. Under ordinary
circumstances, the unit will be powered by 110 or 220 Vac with the ac adaptor
provided. This is the preferred mode of operation.
The recorder can also
operate via 4 “D” size batteries installed in the rear of the unit which will
power the unit up to 30 days.
The system may be restarted by changing the batteries or by the re-initiation of
ac power. If ac power fails, the circuitry will attempt to automatically switch to
battery backup. If viable battery power is available, the system will operate on
battery power until the batteries fail or ac power returns. When ac power
returns, the recorder will automatically reset itself (refer to Section 8.5).
Typically, the unit will operate with fresh alkaline batteries for about 1 month. It
should be noted that to conserve battery power, the system timing turns the
sensors on and updates the display and pen position only once every 0.5, 3.5 or
16 minutes while in the 1, 7 or 32 day modes respectively. However, the display
remains in continuous operation during battery operation. You should be aware,
then, that during battery operation it is possible for the display and pens to lag
behind actual ambient conditions by up to 0.5, 3.5, or 16 minutes to save power.
Only when using the ac adaptor do the display and pens constantly update for
changes in ambient conditions.
Technical Details
10
10-2
Summary of Contents for CT485B-110V-G-AL
Page 23: ...Setting Up the Recorder 2 2 14 Notes...
Page 27: ...Powering Up the Recorder 3 3 4 Notes...
Page 33: ...Alarm Operation 4 4 6 Notes...
Page 43: ...Using the Cal Lock Kit 6 6 2 Notes...
Page 45: ...Using the Voltage Input Adapter Optional 7 7 2 Notes...
Page 49: ...8 4 Notes Maintaining the Recorder 8...
Page 57: ...Specifications 11 11 4 Notes Notes...
Page 59: ...CE Approval 12 Notes 12 2...
