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7.8 WATLOW Series 988 User’s Manual
Tuning, Manual Operation, Alarms and Error Codes, Chapter 7
Error Codes
[E1`2] [E2`2]: Sensor under-range error
The sensor at the input indicated by the first number generated a value
lower than that allowed for the range of the sensor, or the analog-to-digital
(A/D) converter malfunctioned. Make sure the setting for the input (Input
Menu) matches the sensor type and that the sensor range falls within the
range of the process being controlled.
[E1`3] [E2`3]: Sensor over-range error
The sensor at the input indicated by the first number generated a value
higher than that allowed for the range of the sensor, or the analog-to-digi-
tal (A/D) converter malfunctioned. Make sure the setting for the input
(Input Menu) matches the sensor type and that the sensor range falls
within the range of the process being controlled.
[E1`4] [E2`4]: A/D overflow error
The analog-to-digital (A/D) converter at the input indicated by the first
number is over range. An open or reversed polarity sensor is the most like-
ly cause. Check the sensor. Make sure the input (Input Menu) is set to the
correct sensor type.
The analog-to-digital (A/D) converter input voltage may be too high to con-
vert an A/D signal.
Error Code E1 and E2 Messages
Four dashes, [----], in the upper display indicate a Series 988 error. The
control goes into the manual mode and maintains the percent output
selected at the [FAIL] prompt (Global Menu). That value (percent of out-
put) is shown in the lower display.
[E1`1] [E2`1]: A/D underflow error
The analog-to-digital (A/D) converter of the input indicated by the first
number is under range. An open or reversed polarity sensor is the most
likely cause. Check the sensor. Make sure the input prompt is set to the
correct sensor.
TLTL
WW
WW
AA
PROCESS
L1 L2 L3 L4
DEV
% OUT
DISPLAY
SERIES 988
MODE
AUTO
MAN
Figure 7.8 -
Error code display.
˜
NOTE:
An alarm display
will be masked by
an error condition
or when the control
is in the Calibration
or Setup menus.
˜˜
NOTE:
To view the error
code press the
Auto/Man key å
once. The upper dis-
play shows the
error code for five
seconds before
returning to the
[----] display.