Hello everyone, i have been using masso since the past year without any trouble. Two days ago, the proximity switch of the Y axis started to blink from low to high and vice versa. The sensor is fine, I've checked it by replacing it with X axis sensor input. The masso input port is also fine, when i switched the y input to x input. Can anyone help me out?
Trouble with home sensor input
- Thread starter sourabh
- Start date
zombieengineer
ZombieEngineer
Can you use a multi-meter and measure the voltage at the MASSO controller between the input pin and GND?
For logic low should be < 1.0V
For logic high should be > 3.5V (based on TTL logic standards)
The actual trigger point for logic high is highly dependent on the components. The opto-isolator chip has a wide variation in sensitivity, not uncommon to see a factor of 12 between the lowest and highest current gains on a datasheet. It is quite possible that the trigger voltage for logic high can vary between 1.2V to 3.4V (0.2V to 2.4V above the logic low threshold, it could be lower than that based on the actual circuit on the other side of the opto-isolator).
The LED in the opto-isolator chip has a "forward voltage" range of 1.0V to 1.3V (hence the logic low threshold above). I believe MASSO has added a 6800? resister in series with the opto-coupler from my investigations.
If you are using a resistor in the input circuit: The ideal resistor to get 5V at the input terminal is given by R = 1700 x (V - 5), for V=24 then R=32.3K?, for V=12 then R=11.9K?.
Using a lower value resistor is acceptable, just means the input terminal voltage will be a bit higher.
I have just checked the triggering voltages the inputs on my MASSO G3 controller and the following are the results:
I do have an outlier (Input 9) which goes low below 1.26V and high above 1.33V (looks like I have a suspect input).
For logic low should be < 1.0V
For logic high should be > 3.5V (based on TTL logic standards)
The actual trigger point for logic high is highly dependent on the components. The opto-isolator chip has a wide variation in sensitivity, not uncommon to see a factor of 12 between the lowest and highest current gains on a datasheet. It is quite possible that the trigger voltage for logic high can vary between 1.2V to 3.4V (0.2V to 2.4V above the logic low threshold, it could be lower than that based on the actual circuit on the other side of the opto-isolator).
The LED in the opto-isolator chip has a "forward voltage" range of 1.0V to 1.3V (hence the logic low threshold above). I believe MASSO has added a 6800? resister in series with the opto-coupler from my investigations.
If you are using a resistor in the input circuit: The ideal resistor to get 5V at the input terminal is given by R = 1700 x (V - 5), for V=24 then R=32.3K?, for V=12 then R=11.9K?.
Using a lower value resistor is acceptable, just means the input terminal voltage will be a bit higher.
I have just checked the triggering voltages the inputs on my MASSO G3 controller and the following are the results:
Minimum | Typical | Maximum | |
Logic Low | <2.67 V | <3.03 V | < 3.25 V |
Logic High | >2.83 V | >3.25 V | > 3.47 V |
I do have an outlier (Input 9) which goes low below 1.26V and high above 1.33V (looks like I have a suspect input).
zombieengineer
ZombieEngineer
It appears that Input 9 on the MASSO G3 is intentionally different to the other inputs - it appears to have the same circuit as the three encoder inputs (high speed opto-isolator with a lower series resistance).
Leaves me scratching my head asking the question - Why?!?
Leaves me scratching my head asking the question - Why?!?