ABCDEFGHIJKLMNOPQRSTUVWXYZ
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Escort TD System commands for firmware version 1.6.4. and higher.
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All commands/requests are sent from an external device in the following format:
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Prefix
network number/address
CommandDataCheck sum
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0х31u8(net_num)(See the list of commands)Can be absentCRC-8 (Maxim)
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Prefix
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0x31
request from the computer/external device
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0x3Esensor response
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The list of commands/requests
DataNote
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0x06
request for data in Omnicomm format
None
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0xFF
command to poll the network
None
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The response is rendered in the following format:
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Prefix
network number/address
Command/RequestDataCheck sum
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0х3Еu8(net_num)(See the list of commands)
Can be absent (depends on the command sent)
CRC-8 (Maxim)
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Commands/requests
Response bytes's description
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0x06Transmission of the data in the Omnicomm formattemperature -U8U8 - 2 digits
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U16- fuel level readingU16 - 4 digits
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U16 — reserved bytes (not used)
U32 - 8 digits
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0xFF
Command to poll the network
U8 net_num
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Example of response to the 0x06 command
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PrefixNetwork addressCommand Checksum
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Request0х31u8(net_num)0x06CRC-8 (Maxim)
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Network addresses of the sensors are set within the range from 0 to 255 (net_num)
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Each sensor emits its own number in the time gate corresponding to the sensor network address.
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gate time for a sensor's response - 1 ms.
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For example if there are two sensors with the network addresses 1 and 100,
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the value from the first sensor (with the network address 1) comes in 10 + 1 ms, the value from the second sensor (with the network address 100) comes in 100 + 10 ms.
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10 ms separate each instance of the data transmission / reception by the converter USB-RS485 /
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CRC calculationYou can can use the following algorithms to calculate the checksum
with a polynom ^8 + a^5 + a^4 + 1 (C language)
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U8 CRC8(U8 data, U8 crc)
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{1 U8 CRC8 (U8 b, U8 crc)
2 {
3 U8 i = 8;
4 do {
5 if ( (b ^ crc) & 0x01) {
6 crc = ( (crc ^ 0x18) >> 1 ) | 0x80;
7 } else {
8 crc >>= 1;
9 }
10 b >>= 1;
11 } while (--i);
12 return crc;
13 }
1 U8 CRC8(U8 data, U8 crc)
2 {
3 U8 i = data ^ crc;
4 crc = 0;
5 if(i & 0x01) crc ^= 0x5e;
6 if(i & 0x02) crc ^= 0xbc;
7 if(i & 0x04) crc ^= 0x61;
8 if(i & 0x08) crc ^= 0xc2;
9 if(i & 0x10) crc ^= 0x9d;
10 if(i & 0x20) crc ^= 0x23;
11 if(i & 0x40) crc ^= 0x46;
12 if(i & 0x80) crc ^= 0x8c;
13 return crc;
14 }
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 U8 i = data ^ crc;
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 crc = 0;
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 if(i & 0x01) crc ^= 0x5e;
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 if(i & 0x02) crc ^= 0xbc;
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 if(i & 0x04) crc ^= 0x61;
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 if(i & 0x08) crc ^= 0xc2;
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 if(i & 0x10) crc ^= 0x9d;
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 if(i & 0x20) crc ^= 0x23;
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 if(i & 0x40) crc ^= 0x46;
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 if(i & 0x80) crc ^= 0x8c;
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 return crc;
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}
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