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distant outstations. Each time a command is received the outstation re-starts the Stay Awake period.
When the Stay Awake period lapses, the outstation will switch to Sleep Mode:
7.1.2.4 Sleep Mode
The outstation switches off all internal functions, except for a very low power timer, so power consumption is
minimised. Every second it briefly wakes to check switches S1 and S2. If either has been changed the
outstation will reset itself.
If any digital input changes state the outstation will briefly wake up and increment the relevant counter. If
digital exception reporting is enabled for the relevant digital input (see 9.3) the outstation will transmit an
unsolicited message to the base-station, repeated at random time intervals until the base-station acknowledges
receipt.
If analogue exception reporting is enabled the outstation will periodically wake from sleep mode, read the
analogue inputs and compare them with the last values sent to the base-station. If a significant change has
occurred it will transmit an unsolicited message to the base-station, repeated at random time intervals until the
base-station acknowledges receipt.
Two seconds before the next command is due the outstation will wake up and change to Receive Mode. It will
stay in this mode for up to 30 seconds, during which time the base-station should send its next command. If
no command is received the outstation will return to Sniff Mode.
7.1.3 Power-save mode with 1 second transducer settling time (S2.6…S2.8 = 110)
This mode is intended for use with transducers that take more than 250ms to stabilise, such as fast ultrasonic probes. It
is identical to the normal power-save mode described above, except that the outstation raises 12V when it enters
Receive mode, so the transducers are powered for at least 1 second before the next command is received. The 12V
supply remains raised during the Stay Awake period. If analogue exception reporting is enabled the outstation will
raise
Note that while the outstation is in sniff mode (i.e. when it has lost sync with the base-station) the transducer is not
powered. Its response to the first request will thus not contain the correct analogue values. The next request from the
base-station will receive the correct response.
Obviously, the power consumption in this mode is slightly higher than in normal power-saving mode.
7.1.4 Power-save mode with 4 second transducer settling time (S2.6…S2.8 = 101)
This mode is similar to the normal power-save mode described above, but power is applied to the transducer 4 seconds
before exiting Sleep Mode to allow more time for the transducer to settle. It should be apparent that the longer power is
applied to the transducer the higher the overall power consumption.
7.1.5 Power-save mode with 30 second transducer settling time (S2.6…S2.8 = 100)
This mode is similar to that described above, but allows even more time for the transducer to settle. It should be
apparent that the longer power is applied to the transducer the higher the overall power consumption.
7.1.6 Power-save mode, using digital outputs (S2.6…S2.8 = 010)
Outstations at sites without power are usually input-only, since by definition there is no power to operate any plant that
they could be used to control. The base-station optimises the outstation power consumption by only requesting the
input states it uses, so the outstation does not waste power transmitting unused data.
However, there is one exception, where battery-powered valves are used. These can be controlled by a two-way
switch, to set them fully open or fully closed. In this mode the
Nano_Link
outstation needs to be fully-equipped, so its
digital outputs can be used to control a magnetically-latching relay to switch the valve. (The
Nano_Link
digital
outputs de-energise when the outstation enters Sleep Mode, so their state must be stored magnetically).
A
Micro_Link
base-station can be configured to send data to the outstation as well as reading data from it. A
Nano_Link
base-station cannot be configured to enable or disable sending of data to the outstation, so normally only
Содержание Nano Link IP67
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