Page last updated: October 16, 2009
Miscellaneous Drawings
Analog Input Board, EL-1356
Schematic: schematics\4ch_temp_sensor.pdf
Page last updated:
October 16, 2009
This board enables the Galil DMC-40x0 controllers to monitor up to 4 analog inputs. It was originally intended to connect to LM-35 Precision Centigrade temperature sensors but because we made it general purpose enough, it can be configured for other analog input signals as well. The outputs of the individual channels are sent directly to analog inputs AN1-4 of the Galil controller.
Sheet 1 shows channels 1 and 2. Channel 1 is used for and on board LM35 solid-state sensor and channel 2 is avalible via DB9P connector J2. The two channels are set up for, bipolar input. The LM-35 sensors provide a 10mV/° signal that we amplify by a factor of 10 to give the Galil an input of 100mV/° . The output of the op-amp is wired to pins 2 and 10 of the output connector. They will connect to analog inputs AN1 and AN2. J1 is a DB15S circuit board mounted connector. Normally this board will attach directly to the Galil's analog input connector. The temperature sensors are capable of negative outputs and thus R1 and R5 are pulled down to the -12 volt supply. This allows negative temperatures to be read - older versions had the inputs tied to ground through a 1M ohm resister and thus eliminated the possibility of reading temperatures below freezing.
On sheet 2, channel 3 is identical to channel 2 on the previous sheet with the following exceptions. Channel 3's input is connected to connector J3 and is wired to J1 pin 3. Channel 3's output is wired to and is available to read on AN3 of the Galil. Channel 4 is somewhat different from 1 - 3 in that it is setup to monitor the 24-volt main power supply. The input is attenuated by the combination of the inputresistor R13 and gain resistor R16. The attenuation produces an output level near 5 volts, again in the middle of the Galil’s ADC input range. When each board is built and tested, a tag is attached containing output values vs input values for inputs of 20V, 23V, 24V, and 25V. With these values the software should have enough info to flag any supply problems
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