IM 12B6C3-E-E
5-17 Parameter setting
5-3-4. mA output functions
Code 31 OUTP.F When pH is set in code 1 as the main parameter, the output functions may
be set as follows:-
pH
pH (table)
Parameter 2 (ORP or rH as set in code 02)
When ORP is set in code 1 as the main parameter, the output functions
may be set to:
ORP
ORP (table)
Code 32 BURN Diagnostic error messages can signal a problem by sending the output
signals upscale or downscale (21 mA or 3.9 mA)*. 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.
* 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.
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
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