Data Input And Output - AAF SAAFShield Installation, Operation And Maintenance Instructions

8.0 Data Input and Output

The SAAFShield Detecting Unit control logic interface block interprets
the 4-20 mA signal originating in the SAAFShield Communications
Module and produces a set of data consisting of each piece of data
collected by the SAAFShield detecting unit. The block also has some
failure detection capabilities. If a failure is detected the Fail bit is set
and a fail code is populated.
Block Diagram
In
SAAFShield
Qui
Communications
Rst Module
Inputs
Parameter Name Type Description
In DINT Physical IO Tag
Qui Boolean Signal Quality
Rst Boolean Initialize output to starting values
Details
Parameter Name Type Description
FAL Boolean True if QUI is False
CumCu DINT Cumulative Copper reading in angstroms
CumAg DINT Cumulative Silver reading in angstroms
IncCu DINT Incremental Copper reading in angstroms
IncAg DINT Incremental Silver reading in angstroms
RH Real Relative Humidity reading
temp Real temperature reading
error Real error Code
Notes:
The range and unit of measure for all metal readings is 0 – 4000 angstroms.
• Relative Humidity is measured 0 – 100%.
• Temperature is measured -50 – 150º C
Pulse Codes
Variable Number
of Pulses
Start Signal 1
Inter-data Pulse 2
Data Transfer 1
FAL
CumCu
CumAg
IncCu
IncAg
RH
Temp
Error
Pulse Level Length
(raw value) of Time
6.28 mA or 16486 3 seconds
8.58 mA or 22486 1 second each
N/A 5 seconds
Cycle
every 15 minutes the SAAFShield Communications Module sends data
to the analog input (SigIn). It sends the start signal for 3 seconds, waits
2 seconds, and then begins data transmission. each measurement
is transmitted for 5 seconds. there is a two second wait followed by
two inter-data pulses. Then the next measurement sequence is
transmitted. The chart below (Figure 6) shows an example sequence.
Note that all data transmitted is set high. When the Communications
Module has sent all pieces of data, it waits for 15 minutes before
beginning the cycle.
Figure 6.
Steps
1. Send one 6.28 mA pulses of 3 seconds.
2. Wait 2 seconds.
3. Transmit Cumulative copper data in the range of 4-20mA
for 5 seconds.
4. Wait 2 seconds.
5. Send two 8.58 mA pulses of 1 second each with inter-pulse
pause of 1 second (set loop to 4mA during pause)
6. Wait 2 seconds.
7. Transmit Cumulative silver data in the range of 4-20mA
for 5 seconds.
8. Wait 2 seconds.
9. Send two 8.58 mA pulses of 1 second each with inter-pulse
pause of 1 second (set loop to 4mA during pause)
10. Wait 2 seconds.
11. Transmit incremental copper measurement in the range of 4-20mA
for 5 seconds.
12. Wait 2 seconds.
13. Send two 8.58 mA pulses of 1 second each with inter-pulse
pause of 1 second (set loop to 4mA during pause)
14. Wait 2 seconds.
15. Transmit incremental silver measurement in the range of 4-20mA
for 5 seconds.
16. Wait 2 seconds.
17. Send two 8.58 mA pulses of 1 second each with inter-pulse
pause of 1 second (set loop to 4mA during pause)
18. Wait 2 seconds.
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