LTH Electronics HPT63, Руководство по эксплуатации

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9 Current Output
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9 Current Output
The current output menu structure contains all of the necessary set-up functions to
configure the current output source(s). If one current output is fitted, then the menu
will be as follows. If two current outputs are fitted they are referred to as A and B
respectively.
The menu structure is as follows:
O/P Source (A or B)
Sensor
IP
| Select Output (0/4-20 mA)
| Output A/B Zero
| Output A/B Span
Temp IP
| Select Output (0/4-20 mA)
| Output Zero
| Output Span
Disabled
On Error = (No, 22 mA or 0 mA)
The maximum load resistance that the current output can drive depends on the
power supplied to the unit and is: R
load
(Ohms) = (Vpower –2) / 0.04.
9.1 Input
The unit can use the sensor input or the temperature input as the sources for the
current outputs. Alternatively, the source can be switched off by selecting
Disabled
for that source.
9.2 Select Output
The output range for the current output can be set to one of two ranges, either 0 – 20
mA or 4-20 mA. This selection sets the limits of the zero and span output levels.
The output will continue to provide an extrapolated output above (>20 mA) and below
( <4 mA ) these points but will flag an error message on the main display. The
maximum current limit is approximately 22 mA, the minimum limit is 0 mA (i.e. the
unit cannot source a negative current)
9.3 Zero & Span
The zero and span levels define the limits of the source input. This provides a totally
flexible method of configuring the current output. The zero can be set anywhere
within the input source range and the span up to 5% of the range, providing total
control of the output range and offset. An inverse relationship can easily be achieved
by simply setting the zero level to be higher than the span level.