ENDEVCO MODEL 136 DC AMPLIFIER
INSTRUCTION MANUAL
IM136
Page 12
2.4
OPERATION
The Endevco Model 136 can be manually programmed from the front panel (See Figure 1) by
means of a “Select Channel” push-button, three (3) “Channel LEDs”, a “Select Function”
push-button, seven (7) “Function LEDs” indicating which function has been selected by the
“Select Function” push-button (referred in this document as the “function LED's”), a four (4)
character LED display to show the state of each function, four (4) “EDIT” push-buttons to
change the entries in the LED display, and three (3) LEDs indicating if there are any faults in
any of the channels (referred in this document as the “Fault LED's”).
The unit has two modes of operation: (1) Normal and (2) Query/Programming. In the Normal
mode of operation, the unit can be in (a) Monitoring State, or (b) No-Monitoring State. While in
the Normal mode of operation, the selected state will apply to all three channels
simultaneously.
The unit will store the settings for all of the function in its internal memory and at power-up it
will automatically restore the settings from the last session.
2.4.1
Channel Selection
The user selects which channel is being programmed by pressing the “Select Channel” push-
button. Each press of the “Select Channel” push-button will sequentially turn-on one of the 3
“Channel LED's” located to the right of the “Select Channel” push-button indicating the
channel number selected for programming.
The unit will remain in the selected mode/state of operation (normal or query/programming)
while pressing the “Select Channel” push-button.
2.4.2
Normal Mode
1. Monitoring State
In the Monitoring state of operation the unit takes an RMS reading of the signal present at the
output of the selected channel every 500 mSec and displays the value on the LED display in
Engineering Units (EU: the physical variable in RMS being measured by the transducer) or V
out in RMS. This state is activated by selecting either the "EU" or “V out” entry in the "Monitor"
Function selection.
Pressing the “Select Channel” push-button while in the Monitoring state allows the user to
quickly view (sequentially) the signal levels at the output of each channel.
2. No-Monitoring State
The No-Monitoring state allows for low noise operation. This is accomplished by not taking
A/D readings from the outputs, and by placing the CPU in idle mode in order to minimize
power consumption and digital noise in the unit. The LED display will be turned OFF. This
state is activated by selecting the "OFF" entry in the "Monitor" Function selection.