Technical Manual
Page 22
CODEL
OPS.109
Issue : B
Rev. : 1
Date : 23/10/13
Doc. i/d : 0109/6
Ref. : 090028
To change the data displayed, press the
ENTER
key and a, flashing cursor will appear at the beginning of the
concentration units, i.e. m/sec or m
3
/sec. The
and
keys will now change the highlighted parameter. Each
push of the
ENTER
key will select another of the parameters, in the following order:
Units - m/sec or m
3
/sec
Averaging Time - seconds, minutes, hours, or days.
Once the display configuration is as required, press the
ENTER
key when the cursor is flashing on the
averaging time, and the cursor will disappear from the display. The
ENTER
key may be pressed again if
required to bring the cursor back onto the display.
7.5.2. Calibration
The calibration of the flow monitor can be verified by an on-board calibration procedure that may be initiated in a
variety of ways (see 7.9.8.1. Calibrate). The calibration allows a calibration point to be defined at a low flow
value and a second point defined at a high value, allowing verification to be made at two points in its defined
operating range.
The calibration system operates by the signal processor injecting electronic signals into the transducers. The
processor, from the low cal and high cal flow points entered, calculates the time delay in milliseconds that would
be experienced between the two transducers, if the real flow in the duct were at selected values.
The signal, injected into the downstream transducers, is phase-shifted relative to the upstream transducer, by
the computed delay. The monitor then performs its normal correlation process on the value. This computed flow
value should be the same as the value entered for the low cal and high cal flow points.
The calibration cycle consists of two distinct phases, the first being the low flow calibration, the second the high
flow calibration. The status of each phase is indicated by means of a counter counting down on the processor
display.
At the completion of the calibration, (both low flow and high flow), the processor resets automatically to its
normal measurement mode (Mode 1). The resulting calibration data can be viewed from Mode 4
DIAGNOSTICS
. Alternatively calibration data may be outputted to the 4-20mA output during the calibration
process (See Output Data).
7.6. Parameter Mode
In this mode, the parameters set within the set-up mode may be examined, but not changed. Press the
MODE
key until the number 2 appears in the top left corner of the display, then press the
ENTER
key. The
and
keys will now scroll through the available options, press the
ENTER
key to display the selected option.
Press the
ENTER
key again to exit from each option.
See the
SET-UP MODE
for further details of the display information, and how to change the held parameters.
7.6.1. Identification
The analyser type, EPROM program ID and identity number are displayed from this option.
7.6.2. Parameters
The following parameters are examined from this option, selected using the
and
keys:
Detector Separation (Distance)
This is the separation of the detectors in mm; the value is held within the instrument to calculate velocity from
the time delay and should be within ±5mm of the actual separation.