3-4. ma output functions, 3-4. ma output functions -17 – Yokogawa EXA PH202 2-Wire pH/ORP Analyzer User Manual
Page 68
IM12B07D02-01E
Parameter setting 5-17
5-3-4. mA output functions
Code 31
*OUTP.F When pH is set in code 01 as the main parameter, the output functions may be
set as follows:-
0:
pH
1:
pH
(table)
2: Parameter 2 (ORP or rH as set in code 02)
When ORP is set in code 01 as the main parameter, the output functions may
be set to:
0:
ORP
1:
ORP
(table)
Code 32
*BURN
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
signalling 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.
Code 35
*TABLE
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 linearise the
output with a mA curve.
Table 5-2.
4-20 mA
4-20 mA
0%
4.0 mA
50%
12.0 mA
5%
4.8 mA
55%
12.8 mA
10%
5.6 mA
60%
13.6 mA
15%
6.4 mA
65%
14.4 mA
20%
7.2 mA
70%
15.2 mA
25%
8.0 mA
75%
16.0 mA
30%
8.8 mA
80%
16.8 mA
35%
9.6 mA
85%
17.6 mA
40%
10.4 mA
90%
18.4 mA
45%
11.2 mA
95%
19.2 mA
100%
20.0 mA
mA