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Russound CAV Module, passthru?
wirm
Posts: 7
Seems as though i cant get the passthru to work on this module. I've tried with the start and stop bits, without them. With the checksum, without it. The module documentation isnt the clearest thing in the world on this one, it looks like they edited some of the standard doc and didnt quite finish the passthru portion. Anyone ever try this?
Trying to get some feed back to and from the keypads, the protocol lets you send msgs to the keypads which i thought was pretty cool. If anyone has any information that'd be great. thanks
Trying to get some feed back to and from the keypads, the protocol lets you send msgs to the keypads which i thought was pretty cool. If anyone has any information that'd be great. thanks
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If you have any questions about the cav66 duet module give Cody a call at 469 624 6551.
I am in the same Boat, The Module works great, but did not see anything integrated to control the "Radio" portion of the Russound Unit, so i found the strings and tried them through passthrough, and no matter what i did i could not get it to work, always got an invalid character error.
Heres my thoughts on it, and hopefully i'm wrong. Below is the example of how they determine there checksum value, now as the passthrough automatically does checksum calculations, i figured taking out the checksum byte of the string would have sufficed and let the passthrough handle it, but no dice.
"$F0,$00,$7D,$00,$00,$00,$70,$05,$02,$01,$00,$02,$01,$00,$3A,$00,$70,$00,$00,$00,$01,$28,$F7"
so if we removed the checksum value of $28 we would get this.
"$F0,$00,$7D,$00,$00,$00,$70,$05,$02,$01,$00,$02,$01,$00,$3A,$00,$70,$00,$00,$00,$01,$F7"
But the problem is the passthrough is adding the $0D CReturn at the end of the string, and in return i get back a
invalid character, and the string does not passthrough properly, is there a way u can disable check sum calculations in a passthrough command with netlinx?
again maby i am shooting in the complete wrong direction but i have tried everything. the string works fine when i send it direct, the only thing i noticed is there calculation below is a little different to other manufacturers they are using "and" to get the final result. does the Netlinx passthrough do this calculation in its check sum ?
4.4.1 Checksum
All messages include a Checksum that helps protect the integrity of the message. The Checksum is a single
Byte that can be calculated using a formula (see example below). The Checksum itself and the End of
Message Character are not included in the calculation. Only the low 7 Bits are used so overflow is
discarded.
Calculate with calculator in scientific mode.
Checksum Calculation Example:
Byte # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Value F0 00 7D 00 00 00 70 05 02 01 00 02 01 00 3A 00 70 00 00 00 01 28 F7
Step #1 - Add the HEX value of every byte in the message that precedes the Checksum:
Example - F0+00+7D+00+00+00+70+05+02+01+00+02+01+00+3A+00+70+00+00+00+01
In this string, you are adding F0 to the 01 just previous to the checksum of 28
Answer is 293
Step #2 - “Create Byte Count” Count the number of bytes which precede the checksum and convert that
value from DEC to HEX. Add the HEX byte count to the sum from step 1.
Dec count of bytes preceding checksum is 21
21 dec converted to hex is 15
293+15=2A8
Step #3 - AND the value found from step 2 and HEX 7F (step2 value AND 7F = CHECKSUM!)
(and not plus):
Example – 2A8 AND 7F = 28
Checksum = 28
4.4.2 End of Message Character
The End of Message Character (0xF7) is the special HEX value that indicates the end of the message.