Honeywell 700 User Manual page 14

HONEYWELL MODEL 700/800 SIGNAL PROCESSOR AND VIEWING HEAD
The two numeric digits on the Model 700 signal processor
normally display the incoming count during operation; that is,
the number of pulses that arrive between self-check pulses.
This count ranges from 00 to 29.
Refer to Fig. 23 for a flowchart of setting the Relay On
setpoint. Press and hold the RELAY ON SETPOINT key for
two seconds to access this setpoint. The RELAY ON SET
POINT value will be displayed. If no further keys are pressed,
this display will disappear in four seconds and the incoming
count will again be displayed. If the RESET key is pressed,
the display will return immediately to displaying the incoming
count.
While the RELAY ON SET POINT is displayed, you may
increase or decrease the setting by using the INCREASE and
DECREASE arrow keys. To store the new setting, press the
STORE button until "- -" is shown, indicating the value has
been accepted.
To exit the menu at any time without saving changes, simply
press the RESET/rE button or wait 4 seconds until the display
reverts to the incoming count value. To extend the display
time, press the RELAY ON SETPOINT button again; the
display will time out for four seconds after the key is released if
no other buttons are pressed.
The displayed value of the RELAY ON SET POINT is live; that
is, if the relay is off and the adjusted value falls below the
current flame signal count, the relay will turn on immediately
(FFRT settings are ignored). This immediate response can be
seen if the count is low and the RELAY ON SET POINT is set
above it; if the RELAY ON SET POINT is then adjusted down
to the count level, the FLAME ON relay will be energized.
Ratio (%) Relay Off/Relay On Setpoint
For a flowchart of this setpoint process, refer to Fig. 24. The
key labeled RATIO (%) RELAY OFF/RELAY ON is used to set
the RELAY OFF SET POINT at a percentage of the RELAY
ON SET POINT. This percentage is adjustable from 20% to
80%. For example, if the RELAY ON SET POINT is set to 16
and the RATIO (%) is set to 50% (the factory default values)
the relay will energize if the displayed count goes to 16 or
higher and de-energize when the count drops to 08 or less for
one to three seconds, depending on the FFRT (Flame Failure
Response Time) setting. The adjustment of the RATIO setting
is live. Adjustments will cause the Flame Relay to de-energize
immediately, ignoring FFRT settings.
To access this setpoint, press and hold the ACCEPT RATIO/
SET GAIN button for 2 seconds until the current value is
displayed. While the value is displayed, adjustments may be
made via the INCREASE or DECREASE arrow buttons. To
store the new setting, press the STORE button until "- -" is
shown, indicating the value has been accepted.
If no activity occurs for a period of four seconds while the
value is displayed, the RATIO display will disappear and the
old ratio setpoint will take effect.
To exit the menu at any time without saving changes, simply
press the RESET/rE button.
Setting FFRT (Flame Failure Response
Time)
To access the FFRT setpoint, press and hold the FFRT 1/2/3
SEC OPTION button for 2 seconds until the current value is
66-2069EP—04
displayed. Refer to Fig. 25 for the setup flowchart. The FFRT
can be set at 1, 2 or 3 seconds. While the value is displayed,
adjustments may be made via the INCREASE or DECREASE
arrow buttons. To store the new setting, press the STORE
button until "- -" is shown, indicating the value has been
accepted.
The FFRT changes are not live; they take effect only if the
STORE button is pressed. FFRT values do not relate to the
RELAY ON SETPOINT and RATIO (%)/RELAY OFF values.
Therefore, during automatic setup, if the AUTO SET LED is
on, confirmation is not needed to change the FFRT setting.
If no activity occurs for a period of four seconds while the
value is displayed, the FFRT display will disappear and the old
setpoint will take effect.
To exit the menu at any time without saving changes, simply
press the RESET/rE button.
0/4-20mA Output Option
An analog output current is provided for operating a remote
meter or other instrumentation. The load resistance should
not exceed 360 Ohms for the Model 700 signal processors.
The resistance can be chosen to give the desired voltage
swing. For example, if 2V is desired for a 20 mA output, a 100
Ohm resistor would be used. Fig. 26 contains a flowchart for
the mA output setup.
The analog current output selections are 0 to 20 milliamps, or
from 4 to 20 milliamps. Selection of the applicable range is
made by pressing and holding the 0-20 MA/4-20 MA OPTION
button until the current value is shown. 02 denotes the 0-
20mA selection while 42 denotes the 4-20mA selection (the
default value). While the value is displayed, it may be changed
via the INCREASE or DECREASE arrow buttons. To store the
new setting, press the STORE button until "- -" is shown,
indicating the value has been accepted.
Confirmation is not requested if the 0-20/4-20 setting is
changed when AUTOSET LED is on.
The 0/4-20mA output option is live; the operative range
changes as soon as the displayed selection is changed.
However, the value must still be saved via the STORE button
in order to be saved in the signal processor's EEPROM.
To exit the menu at any time without saving changes, simply
press the RESET/rE button or wait four seconds.
The analog current output is scaled according to the RELAY
ON setting. It is scaled so that, if the counts coming in are at a
count rate equal to the RELAY ON setting, the current output
is approximately 13 MA when the range selected is 0-20 MA,
and about 14.6 MA when the range selected is 4-20 MA.
Note that the actual maximum level for the current output is
19.8 MA.
Automatic Setup of Setpoints
With this feature, the Model 700 signal processors set the
RELAY ON SET POINT, the RATIO % (Relay Off), and the UV/
IR GAIN automatically. Calculations for these settings are
carried out in the signal processor as the operator takes the
system through BURNER ON and BURNER OFF sequences.
Fig. 20, 21 and 22 flowchart the automatic setup sequence.
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