
PM IDD 9000 Flame Amplier
372001-02 Rev L
2
The IDD 9000 amplier provides dierent signal-processing circuitry depending on the ame detector
inputs. For example, the UV-4 ame detector head produces a digital pulse train whose frequency varies
with light intensity whereas, the IDD ame detector head produces an analog data signal whose amplitude
and frequency vary with light intensity. Signal processing for the UV-4 input merely blocks low amplitude
noise and then routes the pulses to the input of a digital counter. In contrast, signal processing for the IDD
signal amplies the input, generates an averaged dc voltage level, and converts it into a digital pulse train
output. This pulse train then serves as the input to the microprocessor.
At regular intervals, the microprocessor reads the value of the pulse counter(s) and compares those
values with tuning parameters from memory. When the count value exceeds the corresponding value
from memory, the microprocessor sets a ag to indicate ame presence. These count values also provide
a direct measure of infrared or ultraviolet light intensity striking the respective sensors. Accordingly, the
PCB uses the two count values to generate separate analog output signals that can be used to drive
ame intensity meters.
A serial communication port for each channel is located on the front of the PM IDD 9000. These ports enable
communication between the microprocessors on the board and a hand-held Termiex/ SmartDisplay®
via RS422/RS485 communication protocols. Forney also oers a Windows based software package,
Terminal Emulator Software (TES), that supports diagnostics and tuning of the ame detection system.
If the rmware in the amplier detects an internal failure, it generates a corresponding error message
that can be downloaded to the Termiex/ SmartDisplay®. Any failure will be continually broadcast until
a reset pushbutton is pressed.