15.) No heat or output
Table 7.1 Troubleshooting Chart
Probable Cause(s)
—PCB assembly not in the housing far
enough.
—Poor connection between PCB & keypad.
—No power to controller.
—Power supply board.
—LED’s defective.
—LED driver defective.
—Poor connection.
—Sensor break error.
—Check Sum Error: values in memory may
have been changed accidentally.
—Low Limit Error. The process value is
below the low limit range.
—High Limit Error. The process value is
above the high limit range.
—Incorrect operation of autotune.
—Set point for autotune too low.
—Manual mode not allowable for on-off
control.
—Data failed to be entered into EEPROM
—Overflow Error: Data out of range during
execution of software program.
—Attempt to change a locked parameter.
—Analog portion or A-D converter defec-
tive.
—Thermocouple, RTD or sensor defective.
—Intermittent connection of sensor wiring.
—Wrong sensor or thermocouple type.
Wrong input mode selected.
—Analog portion A-D converter defective.
—Reversed input wiring of sensor.
—No heater power (output), incorrect out-
put device used.
—Output device defective.
—Open fuse outside of the instrument.
—Output device shorted, or power service
shorted.
—CPU or EEPROM (non-volative memory)
defective. Key switch defective.
—Operation of control incorrect.
—Electromagnetic interference (EMI), or
Radio Frequency Interface (RFI).
—EEPROM defective.
Solution(s)
—Receed PCB assembly into the housing.
—Clean contact on PCB.
—Check power line connections.
—Check that power supply board is con-
nected properly.
—Replace LED display or lamp.
—Replace related transistor or IC chip.
—Check connections.
—Check wiring connection.
—Replace RTD or sensor.
—Check program for proper input
—Check and reconfigure control parame-
ters.
—Incorrect input type selected.
—Replaced sensor.
—Readjust
—Incorrect input type selected.
—Replace sensor.
—Readjust
—Proportion band must be greater than 0.
–Repeat Autotune
—Increase set point.
—Increase proportional band.
—Replaced EEPROM.
—Check for electrical noise.
—Unlock parameter
—Replace related components or board.
—Check thermocouple, RTD or sensor.
—Check sensor wiring connections.
—Check sensor or thermocouple type and
if proper input mode was selected.
—Replace related components or board.
—Check and correct.
—Check output wiring and output device.
—Replace output device.
—Replace output fuse.
—Check and replace.
—Check and replace.
—Read the operation procedure carefully.
—Suppress arcing contacts in system to
eliminate high voltage spike sources.
Separate sensor and controller wiring
from “dirty” power lines, ground heaters.
—Replace EEPROM.
Symptom
1.) Keypad not functional.
2.) LED’s will not light.
3.) Some segments of the display or
LED’s are not lit or are erroneously lit.
4.) Process Display shows:
5.) Process Display shows:
6.) Process Display shows:
7.) Process Display shows:
8.) Process Display shows:
9.) Process Display shows:
10.) Process Display shows:
11.) Process Display shows:
12.) Display Unstable.
13.) Considerable error in temperature
indication.
14.) Display goes in reverse direction
(counts down scale as process
warms).
16.) Heat or output stays on but indicator
reads normal.
17.) Control abnormal or operation incor-
rect.
18.) Display blinks, entered values
change by themselves.
–-Repeat Autotune
