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I'm just bumping the thread after 5 days, hopefully someone with good knowlege of the G540 can answer.
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Hi Mariss, I've had a couple of support emails asking about compatibility of the G540 with our new SuperPID router speed controller.
I have downloaded and read the G540 instructions but there are a couple of things I am still unsure about.
If possible could you please answer the following;
1. The 0v-10v analog VFD output on the G540; does it require a separate +10v power source? I am guessing it does as the instructions state it is opto-isolated.
2. If so, can it be supplied with +5v so the abalog output goes from 0v-5v as this is what the PID controller needs. Otherwise, can you confirm the output impedance so I can select resistor values to divide the 0v-10v down to 0v-5v. I have assumed two 10k resistors would be ok at this point.
3. The instructions say the analog output is "50Hz". Can you suggest a filter to integrate this to a analog voltage, currently the Super-PID uses a 10k resistor to 2.2uF cap which may require a larger cap if there is significant ripple component there.
4. The G540 has 4 inputs, I am trying to determine if they are compatible with the logic level output of the PIDs "TACH" output to send the 1 pulse/rev signal back to the PC. The TACH output has a 10k source impedance so the determining factors would probably be the value of the pullups in the G540.
5. The G540 has 2 outputs suitable to control relays, these look to me like open-drain or open-collector drivers so I think they are compatible with the PID's "RUN" logic level input which has an internal pullup resistor of about 22k.
Thank you for any information you can provide.
I'm just bumping the thread after 5 days, hopefully someone with good knowlege of the G540 can answer.
Have you tried emailing Gecko directly?
bob
1) It requires an external 12V supply because the analog output circuit is completely isolated from the rest of the G540 circuit.
2) Do not use less than 8VDC, the circuit isn't designed for 5DC operation.
3) The analog output isn't 50Hz, 50Hz is the PWM frequency. The analog output is a 3-pole active low-pass filter whose 3db cutoff frequency is 5Hz. The filter output has a 55db attenuation of the 50Hz carrier frequency.
4) I am not familiar with the equipment you mention. The G540 inputs require them to be switched to ground or left open to be read as a logical '1' and '0' respectively. This means use a single-pole, single-throw switch from input to ground or an open-collector. Collector to G540 input, emitter to G540 ground. The 'on' current will be 8mA and the open-circuit voltage is 12VDC.
5) The outputs are open-drain. Use a lower resistance pull-up resistor. 22K is much too large and you will be susceptible to noise induced false readings. 470 Ohms to +5VDC is much better.
Mariss
Thank you very much Mariss. You have provided all the information I need.
It all seems compatible enough apart from 4 which means the logic level tach output from the SuperPID won't be compatible with the G540 inputs which need an open-drain driver. That's OK, I can work around that at my end.
Thanks again for your time.
Mariss, I have another question re the G540 inputs.
Can you specify the input voltage levels required to generate the LOW and HIGH results from the G540 input?
I need to connect a CMOS logic level output driver to the G540 input, and the CMOS driver produces 0v and 5v output levels.
Can this CMOS driver operate the G540 input if it was connected through a small series resistor (say 2.7k)?
The CMOS driver is tolerant of the 8mA pullup to 12v you posted, as it has a diode to the 5v rail so it will not be damaged by the G540 pullup or by the 5 to 8mA sunk accordingly. Any information you can provide is much appreciated.
The G540 inputs are optoisolator LEDs in series with 1.5K resistors. The 1.5K resistor returns to an internal +12VDC source inside the G540. Sinking an input to GND completes the current path and turns the input 'on'. They are intended to be driven SPST switches or open-collector outputs.
Mariss
Thank you Mariss.
One customer has been driving the G540 input successfully with a CMOS 0v-5v squarewave output, through a 3.9k series resistor.
Based on what you just said that makes sense and I can't see any reliability issues, and the customer has it working now so my tech support job is done.
I am surprised there has not been more people needing to drive the G540 inputs with logic level 0v-5v signals? I would have thought that was a fairly typical application.
Maybe this thread will explain why my NO optical home switches are not working on my christmas present (new G540). They are Honeywell HOA6335-2, I cannot find a datasheet on them, I'm using a 5vdc power supply to drive them. In the mach3 diags screen when I trigger the sensors I do not see a change on the lpt port pins.
Sorry I'm not trying to hi-jack this thread, just trying to figure out the inputs on the G540.
Put a voltmeter on the output of the home switches (that connects to the G540 input), and check what the 2 voltages are for the 2 switch states. That should give you a good starting point.
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