Honeywell VC4 User Manual page 152

Concentration - 4 byte floating point
Number in PPM
Flow - 2 byte integer in CC/min
Point status - 1 byte
0x01 - point disabled in config
0x02 - point disabled now (It may have become disabled because of a fault.)
0x04 - point locked out
0x08 - low flow
0x30 - (2 bits) concentration summary integer. The meaning of this field is as follows:
00: 0.0 == Concentration
01: 0.0 < Concentration < AL1
10: AL1 <= Concentration < AL2
11: AL2 <= Concentration
0xC0 - (2 bits) current alarm level
00: no alarm
01: alarm level 1 active
10: alarm level 2 active
(End of Point Structure)
Total size is 34 bytes
Example
The following example is an illustration of the above packet using serial communication
protocol version 2. The address of the slave is 42 (0x2A). Point 1 is in a level 2 alarm, but the
gas concentration has decreased below AL2 and AL1 to 42.2 ppb. The other three points are
reading zero concentration. The instrument fault relay is activated and point 4 is disabled
because of loss of flow. Both the Fault History and the Alarm History have new entries which
have not been read yet. Point 3 is configured to be disabled via menu function 3.1. All four
flows are near the norm of 180 cc/min except for point 4, which is 139 cc/min.
Master: 40 2A 00 06 45 4B;
Slave: 40 00 2A 27 45
3D;
3D 2C E2 19
00 00 00 00
00 00 00 00
00 00 00 00
5E;
VC4™
23 64 66 DA;
00 BB 90;
00 BD 00;
00 C4 03;
00 8B 0A;
152
inquiry
header, date/time
unit status byte
point 1 data
point 2 data
point 3 data
point 4 data
checksum
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