Hanna Instruments HI520 - Cleaning Mode; Overview of Cleaning Types

101 Cleaning Mode
19. CLEANING MODE
Data acquisition is done by digital probes via specific sensors.
Due to process conditions sensors can get clogged. To maintain accurate and reliable data, the HI520 has
implemented the cleaning control function as a basic feature.
When in cleaning mode, the controller activates an external device (e.g. a pumps or valves).
Cleaning control block provides a specific sequence on cleaning outputs based on two control algorithms: Simple
cleaning and Advanced cleaning.
Cleaning Control
&
Sequencer Block
Cleaning enabled Sample rate
Calendar
Timer
External digital input
Cleaning output
Controller status
Figure 47: Cleaning Control & Sequencer Block
19.1. OVERVIEW OF CLEANING TYPES
Cleaning Triggers Associated Relay Steps
Simple
water only
• internal triggers
(timer¹, schedule²)
• external trigger
• manual start
any non‑assigned relay
can be set as Rinse Relay
• instrument enters HOLD mode
• configured relay(s) is (are) energized
Advanced
water
detergent
• internal triggers
(timer¹, schedule²)
• external trigger
• manual start
any non‑assigned relay
can be set for advanced
cleaning (i.e. at least one
Rinse Relay and Wash
Relay)
• instrument enters HOLD mode
• rinse is energized (pre‑rinsing
phase)
• wash is energized (detergent phase)
• wash is de‑energized (post‑rinsing
phase)
¹ If the trigger is set to timer, entering in a Hold mode that overlaps with the trigger will add a delay to the
cleaning cycle.
² If the trigger is set to schedule, entering in a Hold mode that overlaps with the trigger of the next start time
and exceeds the set time, the trigger will be lost. The trigger will still be activated if the internal clock doesn't
get past a minute over start time.