Instruction Manual

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GNAV540UserManual
7430‐0808‐01Rev.B
Page67
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Chapter9. CommunicatingwiththeGNAV540
Communicationcommandsareusedtoverifyaunitispresentandalive.
Unit
PingCommand
Table15PingCommand
Ping(‘PK’=0x504B)
Preamble PacketType Length Termination
0x5555 0x504B ‐ ‐
Thepingcommandhasnopayload.Sendingthepingcommandwillcausetheunittosendapingresponse.To
thandCRCfieldsarenotrequired.
facilitatehumaninputfromaterminal,theleng
Example:0x5555504B009ef4or0x5555504B
PingResponse
Ping(‘PK’=0x504B)
Preamble PacketType Length Termination
0x5555 0x504B 0x00 <CRC(U2)>
Theunitwillsendthispacketinresponsetoapingcommand.
EchoCommand
Table16EchoCommand
Echo(‘CH’=0x4348)
Preamble PacketType Length  Payload Termination 
0x5555 0x4348 N <echopayload> <CRC(U2)>
Theechocommandallowstestingandverificationofthecommunicationlink.Theunitwillrespondwithanecho
responsecontainingthe
echodata.TheechodataisNbyteslong.
EchoResponse
Table17EchoResponse
EchoPayloadContents
Byte
ffset
O
Name Format Scaling Units Description
0 echoData0 U1 — — firstbyteofechodata
1 echoData1 U1 — — Secondbyteofechodata
… … U1 — — Echodata
N‐2 echoData... U1 — — Secondtolastbyteofechodata
N‐1 echoData… U1 — — Lastbyteofechodata
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