Slightly OT: Overspeed and Zero Speed detection

Ken Roach

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I have an application where I have to detect the start of motion (non-zero-speed) quickly, and also be able to detect overspeed of around 3000 RPM.

The sensor is a simple 60 pulse per revolution quadrature output encoder.

I've found devices that give me zero speed detection, and devices that give me overspeed detection. The IFM DD110S (overspeed) and DA102S (zero speed) and Rockwell MSR75 (zero and safe speed zone) have all been used by my co-workers.

But as far as I can tell, all of those have either zero-speed or over-speed or safe-speed-range detection. They don't do both zero-speed detection and overspeed detection in the same module.

And it doesn't really need to be a safety device; the functions are to protect well-guarded machine elements, not to protect people.

I can run these encoders into a motion controller, or into a MicroLogix 1400's high speed counter, if I'm willing to expand the budget. But my boss would prefer the simplicity of a dedicated purpose relay.

Any suggestions ?
 
I have an application where I have to detect the start of motion (non-zero-speed) quickly, and also be able to detect overspeed of around 3000 RPM.

The sensor is a simple 60 pulse per revolution quadrature output encoder.

I've found devices that give me zero speed detection, and devices that give me overspeed detection. The IFM DD110S (overspeed) and DA102S (zero speed) and Rockwell MSR75 (zero and safe speed zone) have all been used by my co-workers.

But as far as I can tell, all of those have either zero-speed or over-speed or safe-speed-range detection. They don't do both zero-speed detection and overspeed detection in the same module.

And it doesn't really need to be a safety device; the functions are to protect well-guarded machine elements, not to protect people.

I can run these encoders into a motion controller, or into a MicroLogix 1400's high speed counter, if I'm willing to expand the budget. But my boss would prefer the simplicity of a dedicated purpose relay.

Any suggestions ?

Milltronics?
Anti-plugging switch?
 
Pepperl+Fuchs brand, model: Frequency Converter with Trip Values KFD2-UFC-1.D I think this will do what you want. It accepts a pulse input and calculates a speed and provides an analog output representing the speed and has 2 programmable relay outputs that can be configured to trigger on a max speed and min speed. There are a lot more options that it can be programmed for.

Here is a link: http://www.pepperl-fuchs.us/usa/en/classid_1830.htm?view=productdetails&prodid=48335#js-mod-tabbersystem-jumper-0
 
I need to detect motion starting within about 100 milliseconds. It doesn't have to be very accurate; this is a torque control application that will be running a couple hundred RPM at the most, unless a coupling or mechanism breaks.

The main controller is a Delta Computer Systems RMC150, but it's handling six axes (analog command, analog feedback) already so I can't add enough encoder inputs to also handle this feature (I need six) using "Q" or "U" modules.

The Banner Safe Speed Monitor device ticks most of the boxes but I'm not sure it can respond quickly enough... I'll have to take a close look at the precision that's really required.
 
I need to detect motion starting within about 100 milliseconds. It doesn't have to be very accurate; this is a torque control application that will be running a couple hundred RPM at the most, unless a coupling or mechanism breaks.

The main controller is a Delta Computer Systems RMC150, but it's handling six axes (analog command, analog feedback) already so I can't add enough encoder inputs to also handle this feature (I need six) using "Q" or "U" modules.

The Banner Safe Speed Monitor device ticks most of the boxes but I'm not sure it can respond quickly enough... I'll have to take a close look at the precision that's really required.
Sorry for the delay. I was out of the office last week.
I am confused. The 6 axes provide velocities and accelerations every millisecond. There is even a stopped bit and a parameter for how "stopped" the axis must be before the stopped bit is set.
Are you talking about a 7th input? Configure it as a half axis so the same position, velocity and acceleration information is available for that axis.
You need to write a user program to detect the high speed. There is already a stopped bit feature included as part of the firmware.
Do you have a torque input? If so we have a speed or position with force, pressure or torque limiting modes.
The best thing to do is call us so we get get the best solution.
 

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