Ma Output Functions - YOKOGAWA SC202G 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 12D08B02-01E
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 when HART or distributor comm. is
non-used, 3.9 mA when HART or distributor comm. is used). 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.
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 %
Table 5-3.
Code 4-20 mA
Output
0 4.0
5 4.8
10 5.6
15 6.4
20 7.2
25 8.0
30 8.8
35 9.6
40 10.4
45 11.2
50 12.0
55 12.8
60 13.6
65 14.4
70 15.2
75 16.0
80 16.8
85 17.6
90 18.4
95 19.2
100 20.0
% H SO mS/cm Default
2 4
Service Service
code 55 code 35
0.00 0 0
1.25 60 50
2.50 113 100
3.75 180 150
5.00 218 200
6.25 290 250
7.50 335 300
8.75 383 350
10.00 424 400
11.25 466 450
12.50 515 500
13.75 555 550
15.00 590 600
16.25 625 650
17.50 655 700
18.75 685 750
20.00 718 800
21.25 735 850
22.50 755 900
23.75 775 950
25.00 791 1000
mS/cm