AR3000 User’s Manual
24
Rev 1/10
Analog Output Operation (QA, SE)
The analog output uses two wires in the basic configuration see section 4.1.4.
The analog output is updated with each sample result according to combination effected by the
measurement frequency and the sample averaging. The analog output will deliver a current which
increases linearly from 4 mA at the Zero-point to 20 mA at the Span-point.
5.6.
Analog Output Zero-point and Span-point (QAx y)
These parameters specify the Zero-point (4 mA value) and Span-point (20 mA value) for the
analog output signal. The factory default setting is QA1.000 300.000 for a Zero-point (x) of 1
meter and a Span-point (y) of 300 meters.
Type
QA<Enter>
to display the current analog output Zero-point and Span-point.
Type
QA x y<Enter>
to set the parameters, which must be separated by a space. The space
before parameter x is optional. Values not entered are taken as zero. The combinations of
parameters x and y are compared to sample results, which are affected by the scale factor and
distance offset values (SF and OF - See section 7.2).
The serial port will respond by displaying the new values.
x
specifies the analog output Zero-point (4 mA value) with a resolution of approximately
0.001.
y
specifies the analog output Span-point (20 mA value) with a resolution of approximately
0.001.
It may be desirable to assign the Zero-point and Span-point to anywhere within the sensor’s
measurement range. The Zero-point may be a value larger than the Span-point. In this case, the
range will increase as the sample result decreases.
5.7.
Error Mode (SE0, SE1 or SE2)
This parameter specifies the behavior of the AR3000 analog output signals during error
conditions E02 (common) and E04 (See Error Messages section 5.3 for more information). The
default setting is SE1. This parameter also affects the alarm output error mode. See section 6.2.
Type
SE<Enter>
to display the current error mode.
Type
SE x<Enter>
to specify the error mode.
The serial port will respond by displaying the new values.
x
: specifies the analog output behavior during an error condition:
0
will cause the AR3000 to output and hold the last valid analog output
1
will cause the sensor to output 3 mA to report an error
2
will cause the sensor to output 21 mA to report an error
