Honeywell 5704 Operating Instructions Manual page 165

MAN0448_Issue 13_01-2010
005704-M-5001 A03249
CHAPTER 7 - ENGINEER'S OPERATING
INSTRUCTIONS
(5) Check that the selected control card digital display indicates the
required span gas concentration to be used, if not, use the (
( ) push-buttons to raise or lower the indication until the correct
concentration is displayed.
Note: 1. The analogue display will continue to show the current sensor
live signal level.
2. Pushing the
to the selected mode without any changes to the original span
setting.
(6) Apply the span gas at a flow rate and for a time according to the
selected channels sensor instruction manual.
Note: 1. Apart from oxygen, every sensor should be zeroed before
being spanned. See Section 8.
2. Although a Span Gas as low as 15% of the fsd value of the
sensor may be used, it is recommended that a value of 40%
or above is used.
(7) When the message display shows
push the push -button. The selected control card will then display
on the digital display while it carries out the following:
a. Adjusts its span calibration parameter to the new displayed
value, providing this is within the configured upper and lower
span signal limit values.
b. Set the last calibration date to the current date and reset the
calibration reminder if this is enabled.
c. Automatically return to the normal selected state, however, the
inhibit on the control card channel will remain active.
d. If the displayed value is outside the stored signal limits, display
an error message.
e. On control cards for catalytic sensor inputs, the present sensor
signal will be compared with that recorded when the sensor
was new. A warning will be displayed if the sensitivity of the
sensor has fallen to below 50% of its original value.
button at this stage will return the control card
7-12
5704 Control System
to indicate a stable reading,
) and