Campbell Scientific LoggerNet Datalogger Support Software - Manual (Page 456)

Section 13. Implementing Advanced Communications Links
13.1.2 Operational Considerations
13.1.2.1 Scheduled Data Collection
The intervals for scheduled data collection need to be set up to allow time for
the communications link to be established. Keep in mind that the phone
modem requires 15–20 seconds to dial and establish communication. Also
each link in the RF connection requires 3–5 seconds to link to the next device.
This means that a phone to RF network with 2 repeaters could take over 30
seconds to establish the link and start collecting data. The amount of time
required for collecting the data will vary, depending upon the amount of data to
be collected and the speed and integrity of the communications link. Some
time is also required to close down the link before another station can be
contacted. Make sure the collection schedule allows enough time for each
station to be contacted before contacting the first station again.
13.1.2.2 Extra Response Time
LoggerNet is pre-programmed to expect certain response times from devices
depending on the type of intermediate devices and the communication rates
chosen. If the datalogger network communications link is marginal, it may
take longer to negotiate communication between the devices. Extra response
time added to one or more of the devices may help to prevent the software
from timing out. Note that the extra response times added for each device are
cumulative for the entire communications link, and the total response time
includes the default times plus any extra response time that has been added.
13.1.2.3 RF Address
The hardware settings for the address of the RF base must be 255 for phone to
RF operation. Additionally, ensure that the addresses set for the RF remote
hardware match the settings defined in Setup.
13.1.2.4 Max Time Online
The Max Time Online setting is used to force LoggerNet to terminate a
connection if the maximum time limit is exceeded. This is used to prevent a
phone modem from getting stuck online and incurring extra long distance
phone charges or inhibiting scheduled data collection from other stations. In
phone to RF systems this value should be long enough to allow data collection
for the anticipated amount of data. If the Max Time Online is reached,
LoggerNet will force the connection to close, even if it is in the middle of
collecting data.
13.1.3 Attaching a Datalogger to the RF Base
Connecting a datalogger at the RF Base in a Phone to RF system requires some
additional configuration. The operational considerations are the same as for
the standard Phone to RF network. (See Section 13.1.2, Operational
Considerations.)
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