CS SR50A, Инструкция по эксплуатации

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Appendix D. RS-232 and RS-485 Operation
D-7
It is possible to download a firmware update to the SR50A via the RS-232 or
RS-485 communication interface. Higher baud rates may be desirable to speed
up this process.
It may take up to 30 minutes using a speed of 1200 bps, 7 minutes using 9600
bps, or 3 minutes using 38400 bps.
D.4.2 Address
The factory default address is 33. For RS-232 applications, use the factory
default address. For RS-485 operation, multiple sensors can be polled
individually if different addresses are assigned.
D.4.3 Operational Mode Setting
Three different operational mode settings are available on the SR50A. Overall
system design and desired performance determine which mode to select. The
SR50A operation for each of the three different modes are described below as
well as the advantages and disadvantages of each mode.
D.3.3.1 Measure in Poll Mode
In this mode, the SR50A remains idle until a measurement command is sent
( p33<CR> ) where 33 is the default serial address. After receiving the
measurement command, the SR50A immediately begins a measurement and
transmits the resulting data packet when the measurement is complete.
Typically, the SR50A transmits the data packet within 1 second of receiving
the command packet.
• The SR50A only performs a measurement when requested.
• The data output will lag the measurement command by 1 second.
•
This configuration is conducive to a multidrop RS-485 system where
individual sensors do not transmit data until they are addressed.
D.3.3.2 Auto Measure Auto Output Mode
In this mode, the SR50A automatically exits its low power mode, initiates a
measurement, and outputs the data. The frequency that the SR50A performs
these functions is set by adjusting the Measurement Interval Units and the
Measurement Interval Value parameters.
• No command is required from an external device to obtain a measurement.
• The data recorder or equipment simply needs to read the incoming serial
data from the SR50A.
D.3.3.3 Auto Measure Polled Output Mode
In this mode, the SR50A automatically exits its low power mode and initiates a
measurement. The output data string is not sent until a poll command is
received. When a poll command is received by the SR50A, the output data
typically commences 100 ms after the poll command is sent.