System Warnings - Hach EC1000 Instruction Manual

9.1.3 System Warnings

Display Error Description
ROM ER** ROM failure
RAM ER RAM failure
MARGINAL Marginal calibration
INVALID Invalid keyboard
entry
LOCKED Keyboard lockout
H Output Hold
(flashing in the
first display
location)
* Solution TC
(in the first display
location)
Alarm LED's Alarm Ack
flashing
Table 15 System Warnings
Probable Cause
The instrument ROM failed.
The instrument RAM failed.
During a calibration, the required pH offset
is greater than ±100 mV; the required pH
slope is outside the range of 50.6 to
71.2 mV; or the required temperature offset
is other than +20 °C.
A wrong key was pressed during
programming or calibration or the value
entered is outside the acceptable range.
The keyboard was locked during
programming or calibration.
The output hold function has been enabled
and the recorder, controller, and alarm
outputs are held for 30 minutes (Refer to
Table 1 on page 19).
The solution temperature compensation is
active. (Refer to Section 2.2.5 Initial Setup )
The alarm acknowledge function is active.
This function disables the alarms for 30
minutes. (Refer to Table 1 on page 19).
95
Corrective Action
Replace the microprocessor board.
Replace the microprocessor board.
Recalibrate the instrument or clean or
replace the electrode.
Review the procedure to determine the
correct entry. Redo calibration
or programming.
Unlock the keyboard (see Section
2.2.6 Keylock ).
None
None
None