Detcon FP-700 - Manual (Page 26)

Model FP-700
FP-700 Instruction Manual Rev. 3.0 Page 22 of 40
From the Set Gas Factor text scroll, hold the magnet over PGM1 or PGM2 until the “◄” prompt appears and
continue to hold the magnet in place for an additional 3-4 seconds (until the display starts to scroll “Set
Factor”). The display will then switch to “ X.XX“ (where X.XX is the current cal factor). Swipe the magnet
momentarily over PGM2 to increase or PGM1 to decrease the gas factor level until the correct value is
displayed. Hold the magnet over PGM1 or PGM2 for 3-4 seconds to accept the new value. The display will
scroll “Factor Saved”, and revert to “Set Cal Factor” text scroll.
Move to another menu item by executing a momentary hold, or, return to Normal Operation via automatic
timeout of about 15 seconds (the display will scroll “Set Cal Factor” 4 times and then return to Normal
Operation).
3.5.6 Set Serial ID
Detcon Model FP-700 sensors can be polled serially via RS-485 Modbus™ RTU. Refer to Section 4.0 for
details on using the Modbus™ output feature.
Set Serial ID is used to set the Modbus™ serial ID address. It is adjustable from 01 to 256 in hexadecimal
format (01-FF hex). The current serial ID can be viewed in View Sensor Status using the instruction given in
Section 3.5.2 View Sensor Status.
The menu item appears as: “Set Serial ID”.
From the “Set Serial ID” text scroll, hold the programming magnet over PGM1 or PGM2 until the “◄”
prompt appears and continue to hold the magnet in place for an additional 3-4 seconds (until the display starts
to scroll “Set ID”). The display will then switch to “XX“ (where XX is the current ID address). Swipe the
magnet momentarily over PGM2 to increase or PGM1 to decrease the hexadecimal number until the desired
ID is displayed. Hold the magnet over PGM1 or PGM2 for 3-4 seconds to accept the new value. The display
will scroll “ID Saved”, and revert to “Set Serial ID” text scroll.
Move to another menu item by executing a momentary hold, or, return to Normal Operation via automatic
timeout of about 15 seconds (the display will scroll “Set Serial ID” 5 times and then return to Normal
Operation).
3.5.7 Set Bridge Voltage
Each Detcon plug-in combustible gas sensor requires a one-time setting for optimal bridge voltage. This is set
automatically during the “Set Bridge Voltage” sequence. The “Set Bridge Voltage” sequence determines the
required bridge voltage such that every plug-in sensor operates at exactly 200mA current. This technique
provides for tremendous uniformity in sensor-to-sensor operational performance, and it is notably better than
sensors that are operated on a common fixed bridge voltage platform. The range of bridge voltages required
for Detcon sensors is generally between 2.5 – 2.9VDC.
NOTE: The “Set Bridge Voltage” function is executed during factory calibration of every FP-
700 sensor. In the field, this menu item is only needed when a replacement plug-in sensor is
being installed, or when mating a new FP-700 ITM with an existing plug-in sensor.
The menu item appears as: “Set Bridge Voltage”.
From the Set Bridge Voltage text scroll, hold the magnet over PGM1 or PGM2 until the “◄” prompt appears
and continue to hold the magnet in place for an additional 7-8 seconds (until the display starts to scroll
“Setting Bridge”). The ITM will then display “WAIT”. During the 1-minute sequence, the ITM will display
the three-digit number that corresponds to the bridge current as it is being adjusted. At conclusion, display
will scroll “Set Bridge Voltage”. The new bridge voltage can be viewed in the “View Sensor Status” menu.