UM-0085-B09
DT80 Range User Manual
Page 299
RG
Serial Ports
The serial ports also use a small amount of power while idle, so if they are not required then they can be disabled, too:
PROFILE SERSEN_PORT FUNCTION=DISABLE
PROFILE HOST_PORT FUNCTION=DISABLE
PROFILE USB_PORT FUNCTION=DISABLE
LCD Backlight
Parameter P20 controls the operation of the LCD backlight. By default (
P20=2
), it will switch on when there is user
activity (e.g. key pressed, or USB cable inserted), then switch off a short time (
P17
seconds) later. This should be
adequate for most applications. For minimum power usage it can be forced to be always off by setting
P20=0
.
Maximise Sleep Time
The following guidelines will help maximise the time that the logger spends asleep, thereby minimising power
consumption:
•
Scan as slowly as possible – don't scan every minute if you can get away with scanning every 5 minutes
•
Align schedule intervals to minimise the number of wakeups, even if this means that some schedules sample
more frequently. For example:
RA40S 1V RB20S 2V
is generally better than
RA40S 1V RB30S 2V
because the two schedules are more likely to be processed together.
•
Reduce the
P17
setting (delay before entering sleep mode, seconds), say
P17=5
, so that if a wakeup event
does occur, the logger will go back to sleep quickly.
•
Consider reducing the
P4
setting (wake-up latency, ms), say
P4=100
. This will result in the
DT80
allowing less
time for the wake process than it actually takes, so it will therefore be able to sleep a little longer. Following
wake, the
DT80
will now not have to wait for the schedule's appointed time to come around – it will have already
passed. The schedule will then be executed immediately, albeit slightly late.
•
It is normally not recommended to change the
P3
(minimum sleep time) setting. Sleeping for periods shorter
than 1.5 seconds is generally counter-productive: the additional processing time associated with waking up
outweighs the lower sleep mode power usage, leading to a net increase in the average power consumption.
Optimise Modem Communications
The integrated modem can use a significant amount of power so the aim is to minimise the amount of time spent with the
modem powered up. For example:
•
Upload data infrequently. As shown in
above, unloading every 30 minutes can use 5 times
more power than unloading daily (75mW vs. 13mW)
•
If the volume of data to be transferred is not great, consider using GSM in preference to 3G. Using the DT8xM3
model, you can force it to use GSM with the following profile setting:
PROFILE MODEM SERVICE=GSM
If available in your market, choosing the DT8xM2 model (GSM only) over the M3 will result in an even more
significant reduction in power consumption.
•
If you don't need to interactively access the logger remotely, set the minimum session and minimum idle times
to the minimum value, so that the modem is switched off as soon as possible:
PROFILE MODEM_SESSION MIN_DURATION_S=0
PROFILE MODEM_SESSION MIN_IDLE_S=10
Note:
however that if the connection quality is poor then it may be necessary to increase
MIN_IDLE_S
to avoid unwanted
disconnections cope in the event of long network delays
•
If possible, use SMS rather than email for alarms.
•
For large data transfers, unloading to email may be faster (and therefore use less power) than unloading to an
FTP server because the data is being transferred to the carrier's own SMTP server rather than going over the
Internet to the FTP server. Note however that for email attachments, any binary file (such as a DBD format data
file) must be encoded into printable form for transmission, which can increase the data volume by about 30%.
This is not the case for FTP.
