Idle Mode - Hanna Instruments HI 23 Series Instruction Manual

Note
CONTROL THROUGH ANALOG OUTPUT

IDLE MODE

In order to have the Fail Safe feature activated, an external
power supply has to be connected to the alarm device.
Models HI 23xy1 and HI 24xy1 have a proportional ana-
log output signal (selectable among 0-1mA, 0-20mA,
4-20mA, 0-5VDC, 1-5VDC and 0-10VDC) at the analog
output terminals.
With this signal, the actual output level amplitude is varied,
rather than the proportion of ON and OFF times (duty cycle
control). A device with analog input (e.g. a pump with a 4-
20 mA input) can be connected to these terminals.
IDLE mode is entered through setup code 2.
During idle mode the device performs the same tasks as when
it is in control mode except for the relays. The alarm relay is
activated (no alarm condition), the control relays are not
activated while the analog output remains activated.
When the instrument is in idle mode the red and green status
LEDs are on.
Idle mode is useful to disable control actions when the exter-
nal devices are not installed or when the user detects unusual
circumstances.
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