MC³ 24.96.EX O&M Manual
Page 65
08/14/01 4:34 PM/LDD
LCD Display too dark or too light
1. The contrast of the LCD display is affected by large temperature changes. You may need to
adjust it. The contrast adjustment (R3) is located inside the controller on the backside of the
display assembly in the upper right hand corner.
2. The LCD backlight may be burned out and need to be replaced. This can be verified by
removing the top of the controller and looking at the display assembly. With power applied you
should see light from the backlight coming from the bottom of the assembly.
No load, or bad Load Reading
1. Check all wiring connections.
2. Has the scale been properly calibrated? If not, see Calibrating Your Controller (page 48) for
proper setup procedures.
3. Inoperative PCAD, Counts = 0 or 16,777,215. If there is no response and you are using 5 wire
Load cell connections insure that the sense signal lines are connected to the excitation voltage.
4. Check and make sure the correct number of PCAD’s installed is entered in PCAD Settings
(page 46).
Tacho not counting pulses, or no speed indication
1. Check all wiring.
2. Verify Logical Input “Feeder Block” or “Pulse Block” is not set.
3. Make sure that the correct type of encoder is selected in the setup menu, and the Speed
calibration has been run.
4. In the ‘Large Font Display’ screen, select ‘PULSES’ for one of the displayed values. Verify that
you are receiving pulses from the encoder.
5. Check to see that the correct mode (direction) is selected in Tachometer Parameters (page
29). If R-Hand or L-Hand direction is selected, try setting the direction to “No Direction” and
verify that pulses are detected.
6. Check that the proper number of Tachos installed is entered in Tachometer Parameters on
page 29. The MC³ can support 2 encoders but only channel 1 is used for speed detection.
7. If you are using a Feeder Connection board between the MC³ and the encoder, make sure the
Tacho Pulses switch is in the ‘ON’ position.
No analog Input
1. Check all wiring, make sure that the polarity is correct.
2. If possible, place a current meter in series with the current loop and verify that current is
present and the polarity is correct.
External Totalizer problems
1. Check and verify all wiring and connections are correct.
2. If you are using a DC EMT, check the polarity of the connection between the EMT and the
controller are correct.
3. Check the External Totalizer Parameters on page 44 and verify that the Divide Value and
Pulse Length values are correct for your installation.
General Alarms
1. Refer to General Alarms (page 12) for specific information on each specific alarm condition.
