Campbell Scientific LoggerNet Datalogger Support Software - Manual (Page 83)

Section 4. Setting up Datalogger Networks
Advanced
Use F Command – The “F” command forces the baud rate to 9600. In the
modem enabled (ME) state, the serial I/O port of the end-of-link modem will
communicate with the datalogger at 9600 baud with the “F” command. In the
synchronous device communication (SDC) state, the baud rate from the
computer to the start-of-link modem will be 9600.
Use U Command – The “U” command will force RF communication between
radios to 2400 baud rather than 3000 baud. DC95s purchased before February
1989 can only be used at 2400 baud. For further information see Appendix F
in the Radiotelemetry Network Instruction Manual.
Use W Command – The “W” command will force the RF modem to wait until
there is no carrier detect before transmitting. This option is used when the
computer is connected to more than one RF base.
Custom Dial String – The custom dial string is specifically used to send
commands to an RF95 modem. The values entered into this field will be
inserted between the S command and the string of switch identifiers sent when
the modem is dialed.
4.2.4.9 RFBase-TD
The RFBase-TD device is used to represent a radio base-station modem which
uses the Time Division Polling (TDP) protocol to act as a communications link
between LoggerNet and remote-telemetry radio-datalogger stations. The base
modem hardware must run the Time Division Polling protocol via a TD PROM
or TD-enabled operating system. Hardware that can act as an RFBase-TD
includes the RF500M, RF500B, RF310M, RF310B, and RF315M. The
standard use of the Time Division Polling protocol is to communicate with
PakBus dataloggers using the OneWayData record output method or with table
data dataloggers (CR10X-TD, CR23X-TD, CR510-TD, CR10T) using the Data
Advise record output method.
The child devices of an RFBase-TD are remote radio modems. A child device
can be an RFRemote-TD (table data) or RFRemote-PB (PakBus) depending
upon the type of datalogger connected to the remote radio station’s modem.
When collecting data via radio using the TDP protocol, an RF Polling Interval
is used in conjunction with an RF Poll Offset and a Computer Offset. The
remote radio modems (RFRemote-TD or RFRemote-PB) query the dataloggers
on a time slot given to them by the base modem (RFBase-TD). The base
modem queries the remote modems for data on the specified RF Polling
Interval, factoring in the RF Poll Offset. The base modem buffers this data
until it is queried by the LoggerNet communications server. LoggerNet uses
the RF Polling Interval plus the Computer Offset when collecting the data from
the base modem.
If it is desired to have LoggerNet poll the RFBase-TD for data more frequently
than the interval established by the RF Polling Interval and Computer Offset
settings, the Computer Poll Interval should be set to a non-zero value. In this
case, how often LoggerNet polls the RFBase-TD for data will be determined
by the setting of the Computer Poll Interval, but when LoggerNet polls the RF
Base will be based on the Computer Offset setting.
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