Ma Output Functions - YOKOGAWA SC202G (S) User Manual

5-14 Parameter setting

5-5. mA output functions

mA
Code 31 OUTP.F
Code 32 BURN
Code 35 TABLE
CONDUCTIVITY (S/cm)
1,000
800
600
400
200
0
0 20
CONCENTRATION (%)
25
20
15
10
5
0
0 20
Fig. 5-1. Linearization of output
Example: 0-25% Sulfuric acid
Concentration Output function is done in de following order:
• Set OUTP.F. (Service Code 31) to table
• Set the Concentration range in % (Service Code 55)
• Set table values (%output and Conductivity values) in TABLE (Service Code 35)
IM 12D7B3-E-E
For the SC202 the output may be chosen as linear to input, or configured in a
21 point table to a particular linearization. Enable the table setup in code 31, and
configure the table in code 35.
Diagnostic error messages can signal a problem by sending the output signals
upscale or downscale (21 mA or 3.6 mA). This is called upscale or downscale
burnout, from the analogy with thermocouple failure signaling of a burned-out or
open circuit sensor. The pulse burnout setting gives a 21 mA signal for the first
30 seconds of an alarm condition. After the "pulse" the signal returns to normal.
This allows a latching alarm unit to record the error. In the case of the EXA the
diagnostics are extensive and cover the whole range of possible sensor faults.
* Only when the HART communication is disabled the downscale output signal
is 3.6 mA. When HART communication is enabled the output signal is 3.9 mA.
The table function allows the configuration of an output curve by 21 steps
(intervals of 5%). The following example shows how the table may be configured
to linearize the output with a mA curve.
40 60 80 100
Output in %
40 60 80 100
Output in %
Code 4-20 % H SO
2
Output mA Service
code 55
0 4.0 0.00
5 4.8 1.25
10 5.6 2.50
15 6.4 3.75
20 7.2 5.00
25 8.0 6.25
30 8.8 7.50
35 9.6 8.75
40 10.4 10.00
45 11.2 11.25
50 12.0 12.50
55 12.8 13.75
60 13.6 15.00
65 14.4 16.25
70 15.2 17.50
75 16.0 18.75
80 16.8 20.00
85 17.6 21.25
90 18.4 22.50
95 19.2 23.75
100 20.0 25.00
Table 5-3.
mS/cm Default
4
Service mS/cm
code 35
0 0
60 50
113 100
180 150
218 200
290 250
335 300
383 350
424 400
466 450
515 500
555 550
590 600
625 650
655 700
685 750
718 800
735 850
755 900
775 950
791 1000