Hanna Instruments HI 504 - Manual (Page 52)

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with the cellular engine (for example because the serial
cable is broken or because the cellular engine is not pow-
ered), if the number of available SMS is finished (menu
item P.04) or if the SIM expiration date is overrun.
• The “Power reset” and the “Watchdog reset” errors are active
only for the short time of the start-up session (selftests, pro-
cess name and version displaying). That start-up session ends
when the first measurement is acquired and displayed.
• When the Hold mode is enabled for the “Life check error”,
this error can be closed automatically if the measurement
vary enough.
Note The alarm relay (when configured to be activated) is de-
energized (fail-safe ON) continuously or with a pulse of about
5 seconds. This parameter can be configured through setup
item E.99 (“LE” stands for level and “PULS” for pulse). If
pulse is configured, a new pulse will be let out upon every
new error, no matter whether the red LED is already blinking
(i.e. some error is active) or not. When the pulse finish, the
relay is energized but the error remains still active (red LED
blinking) until the error is closed.
Note The “Digital Transmitter error” is generated by one of the
following causes:
1. Digital Transmitter is off;
2. connection problems between the Process Controller and
the Digital Transmitter;
3. EEPROM data corruption in the Digital Transmitter;
4. Digital Transmitter not calibrated;
5. the Process Controller is configured to pH while the Digi-
tal Transmitter is configured to ORP, or vice versa;
6. other failures in the Digital Transmitter excluding: life check
error, pH electrode broken or leakage, Reference electrode
broken or dirty, old pH probe, dead pH probe, temperature
probe broken error. These errors are handled separately and
exactly in the same way as if they were generated in the Pro-
cess Controller.
To understand which cause generated the “Digital Trans-
mitter error”, the Digital Transmitter must be examined through
its calibrator.
(*): When the Digital Transmitter is used, these errors are
generated in the Digital Transmitter, but they are handled as
if they were generated in the Process Controller.
• If the condition to generate a “Reference electrode broken
or dirty” error is met, the error is not generated immedi-
ately, but first auto-cleaning is performed up to 2 times (the
cleaning type depends upon relays configuration).
If the Reference electrode is not OK after two auto-cleaning,
the “Reference electrode broken or dirty” error is generated.
Note The second auto-cleaning cycle is done only when the first
one is not enough.
Note Both the cleaning modes (simple or advanced cleaning),
when enabled through the relay mode items, are triggered
upon the “Reference electrode broken or dirty” error.
• The “pH electrode broken or leakage” and the “Reference
electrode broken or dirty” errors are never generated if the
correspondent tests are not enabled through setup items I.13
and I.14. The Reference electrode test can not be made if the
Potential matching pin is not in use (see setup item I.04).
• The 3.6 mA fault current is always off unless the 4-20 mA
output has been configured; the 22 mA fault current is
always off unless the 0-20 mA or 4-20 mA output has
been configured.
The 3.6 mA and the 22 mA fault current cannot be both set
to ON. If two errors are active when output is configured
as 4-20 mA (#1 or #2), and one of them is configured for
the 22 mA fault current, while the other one is configured
for the 3.6 mA fault current, the 22 mA current is let out to
the analog output.
The fault current is automatically disabled when the ana-
log output is used for controlling (item O.10 equal to “SEt”),
no matter whether the fault current itself has been config-
ured “On” or “OFF”.
• In case of a “Temperature probe broken” error, the fault cur-
rent, if configured, is let out to both analog outputs (unless
O.20 is equal to “SEt”). In all the other cases only the first
analog output (for pH and ORP) can let out the fault current.
• The “Cellular error” is never activated if the serial lines are
not configured for cellular module connection. The error
will be active if the instrument is not able to communicate