PureAire Monitoring Systems, Inc.
10/25/07
21
Variable
Alias
Read Function Code
Write Function Code
A2D ASCII
31010 (6 bytes)
3 & 4
NA
6 bytes of data representing the scaled span value, including the decimal point.
The first 5 bytes contain the value; the last byte is a space. They are arranged
with the first byte as the MSD with leading zero spacing. For example, with a
span value of 1234 with 1 decimal point, the correct value of 123.4 is returned
for 100% of full scale as follows:
Byte
0
1
2
3
4
5
6
7
8
9
10
Response
Address
04
06 31
32
33
2E 34 20
Crcl
Crch
ASCII
Character
Address
1
2
3
.
4
sp
Crcl
Crch
With the same settings, a 50% of full scale reading of 617 would be:
Byte
0
1
2
3
4
5
6
7
8
9
10
Response
Address
04
06 20
36
31
2E 37 20
Crcl
Crch
ASCII
Character
Address
sp
6
1
.
7
sp
Crcl
Crch
EUNITS
40319-40324
3
6
6 ASCII characters assigned to the engineering units read as bytes.
Measurement 40325-40340
3
6
Name
16 ASCII characters assigned to the unit identifier read as bytes.
Span
40343
3
6
An integer from 1 to 9999 used to scale the A2D ASCII value.
Alm1Setpoint
40345
3
6
Alm2Setpoint
40347
3
6
Integer compared to the A2D Raw value to determine alarm 1 or 2 status. The 0
to 100% set point must be scaled from 197 to 1003. This is done by using
(Alarm%*806) + Offset. Example: A 40% set point would be computed as
(.4*806) + 197.
D.P. Position
40349
3
6
Determines how many decimal positions return with the A2D ASCII value. Valid
range is 0 to 3.
Alm1Trip
40351
3
6
Alm2Trip
40359
3
6
Set to 255 alarms on high, set to 0 alarm on low.
Alm1Latch
40353
3
6
Alm2Latch
40355
3
6
Set to 0 causes alarm 1 or 2 to auto reset, set to 255 causes alarm 1 or 2 to latch.
AlmZoneWord
40357
3
6
16 bit value which may be used as a zone alarm mask for the master.
AlarmReset
2000
NA
5
Setting to 255 causes any latched or acknowledgeable alarms to reset.
InitRtu
2010
NA
5
Setting to 255 causes a restart which applies updated configuration variables.
