RF-Link Technology NL6000 manual Serial Connection to an I/O Device, Carrier Sense Multiple Access

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5.6.5.Carrier Sense Multiple Access

If a unit￿s transmit and receive frequencies are the same, it may be helpful to enable Carrier Sense Multiple Access (CSMA). This option does not allow transmission of a packet until the channel is free of contention.

5.7.Serial Connection to an I/O Device

5.7.1.Basic Serial Parameters

The NL6000 can receive data strings from a variety of I/O devices through its RS232 serial port. Configure the NL6000 serial port parameters based upon how the I/O device will send data to the unit. The following is a list of the basic serial parameters you must configure:

∙Baud rate ￿ This parameter is the data rate between the I/O device and the NL6000 modem. Set the baud rate to the rate of the I/O device.

∙Data bits ￿ This parameter is the number of bits the I/O device sends in a byte. The options available are 7 or 8. The NL6000 does not use parity bits.

∙Stop bits ￿ This parameter is the number of bits used for the end of a byte. The options available are 1 or 2.

∙Transmit Character Timeout ￿ The NL6000 transmits a data packet on the radio channel when there is a timeout on the serial port equal to this value or when the amount of data in the input buffer is equal to the Maximum Packet Size.

5.7.2.Flow Control

Prior to configuration of the NL6000, determine if you want to use flow control to prevent the serial device or modem from overflowing its buffer. If flow control is desired, two types are available ￿ RTS/CTS and XON/XOFF. With RTS/CTS, the modem monitors the RTS signal to determine when to send data to the serial device. In addition, the modem asserts CTS when the modem is ready to accept data from the serial device. RTS/CTS is the preferred method of flow control, but it requires separate lines for RTS and CTS. If you cannot use hardware flow control, you may use the XON/XOFF software option for flow control. This option may only be used for ASCII data and requires the use of special characters to identify when it is OK to send/ receive data to/from the serial device.

5.7.3.DCD Mode

The DCD Mode parameter identifies how the I/O device interprets the current state of the modem using the DCD line between the device and the modem. If the mode is set to Enable, the modem asserts the DCD line when it is receiving data over-the-air. If the mode is set to Disable, the modem asserts the line when it is in a normal operating state and negates the line when it is in

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NL6000 User Guide

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Contents NL6000 Wireless Modem Copyright Table of Contents RF Neulink NL6000 User Guide RF Neulink NL6000 User Guide Product Overview Use the NL6000 in a Simple ConfigurationFeatures Single and Multi- Point Addressing Configuration TemplatesAcknowledgement Auto-TransmitRegulatory Information Safety WarningFCC Part 406.0 to 406.1 MHz OperationGeneral Specifications SpecificationsCurrent Drain at 12 UHF Radio SpecificationsTransmitter ReceiverVHF Radio Specifications Power Connections Hardware Installation and OperationParts Description Serial PortDCE DTELEDs Antenna ConnectionOperation LEDTechnical Support Software ConfigurationPrerequisites PreparationSource and Destination Addressing Unique Data Requirements for a Base StationAddressing with Wildcards Behavior of Repeater UnitsRepeat from a Base to a Remote Repeat to Multiple Remotes using Wildcard Packet Data Options Transmission ModeFEC CRCRF Neulink NL6000 User Guide Acknowledgements Over-the-Air Data RatesDCD Mode Carrier Sense Multiple AccessSerial Connection to an I/O Device Basic Serial ParametersPlanning the RF Channel Factory Default ParametersPre- and Post-Data DCD Time Select Network ä Unit Type ProceduresGeneral Procedures Returning to the Previous Menu Displaying the Configuration Summary WindowSetting the Unit Type Select Network ä Unit Type Radio Network SetupSetting the Unit ID Myid Select Network ä Myid Setting the Target Unit ID ToidSerial Connection Setup Setting the Packet Mode Select Network ä Packet Mode Data SetupSetting the Request ACKs Option Setting the Data Rate Select Network ä Data RateSetting the Contention Option Select Network ä Contention Setting the Max Retries OptionTrigger ID Value Use Repeater SetupFile Management Downloading a Software UpgradeSaving Parameters to Disk Select Save/Restore Parameters ä Save Parameters to DiskRestoring Parameters from Disk Restoring Default Parameters Main Menu Summary Window Menu Quick ReferenceSerial Menu DCD RS-232 SubMenu Network Menu Repeater SubMenu Radio Menu Diagnostics Menu Save/Restore Parameters Menu Other Considerations TroubleshootingDuty Cycle Unit Does Not Enter Programming Mode Use a Fully-Wired RS-232 CableUse a Slower Baud Rate Use a Faster Baud RateSetting the Frequency Trim includes setting Power Appendix a Diagnosing and Correcting Performance ProblemsSetting the Power Value Select Diagnostics ä Transmit Continuous Random Data∙ Select Frequency Trim from the Diagnostics menu Setting the Deviation and BalanceSelect Diagnostics ä Transmit 100 Hz Square Wave ∙ Select Radio Ä Transmit Frequency for Active Channel∙ Select Deviation from the Diagnostics menu Setting the Receive Gain∙ Select Diagnostics ä Receive Diagnostic Mode ∙ Select Diagnostics ä Receive GainCategory Parameter Default Value Custom Value Appendix B Factory Default ParametersFactory Default Values Index RF Neulink NL6000 User Guide
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