Edwards Signaling 5530M-485 - Manual (Page 8)

P/N 3100345 ISSUE 2 PAGE 8
Example: 1F310500
Unit address 1F energizes relay for 5 seconds then shut off automatically. Checksum
characters not used in this example.
Unit address
<31> Two byte ASCII Command 31 echoed back from receiving unit.
Received two byte ASCII time value
Unit received valid message and checksum
The character has a value of 3 hexadecimal and is required at the end of
every message (1 byte).
Receiving unit calculates two-byte checksum and returns ASCII value. Refer to
Section 5.0 for Block checksum calculation and verification.
Note: Relay output commands are only valid when there is no tone/voice message
actively playing. Any tone/voice messages automatically overrides any relay output
commands sent to the unit.
3.7 RELAY DE-ENERGIZE COMMAND - 30
Send Format: 30<00>
Unit address characters (2 bytes). See Section 2.0, Messaging Format
<30> ASCII Command 30 denoting Relay De-Energize (2 bytes).
<00> Two byte ASCII ‘00’ used as protocol padding (two byes)
Assigned unit Zone. Range ASCII A-D (1 byte)
The character has a value of 3 hexadecimal and is required at the end of
every message (1 byte).
Receiving unit calculates two-byte checksum and returns ASCII value. Refer to
Section 4.0 for Block checksum calculation and verification.
Response: 3000
Example: 1F300043
Unit address 1F de-energizes relay output
Unit address
<30> Two byte ASCII Command 30 echoed back from receiving unit.
<00> Two byte ASCII ‘00’ used as protocol padding (two byes)
Unit received valid message and checksum
The character has a value of 3 hexadecimal and is required at the end of
every message (1 byte).
Receiving unit calculates two-byte checksum and returns ASCII value. Refer to
Section 4.0 for Block checksum calculation and verification.
4.0 Verify and Calculate Message Block Checksum
4.1 Message Block checksum can be verified by adding up all the hexadecimal characters in the received message
string, excluding the first character and the very last two checksum characters.
4.2 The sum of these characters will produce a three-byte hexadecimal value. The higher order byte is not used
and should be dropped. The lower two bytes are used for comparison to the received checksum characters.
See example Message String received below:
Message String Received:
0 1 4 3 D A 5 6
Not included in calculation
Message characters
included
Two byte ASCII checksum data field
not included in calculation, but used
for comparison to calculated results