Hi,

I have a LOGO program to control a system where it brings a machine to a safe stop.  There is a problem where under certain conditions (descent) it will not slow down but more likely speed up.

Idea is to use analog watchdog but the speed signal is digital pulses and I haven't found a DAC in the Logo function blocks.

Even if I used a counter I can't see a way to get this to work or am I missing something?

I'd be very grateful for any assistance or suggestions.

Meanwhile I'm looking through various program examples for inspiration.

Matt

See if the attachment works for your application.

I do however think you should look into the reason for the drive speeding up..

Hello William B,

thank you for the suggestion!  I'll have a look when I've finished this reply.

The reason for the drive speeding up is because it is a motor vehicle (off-highway) and the engine speed is forced to neutral,  this does not necessarily mean that the vehicle  will slow down:  If the vehicle is loaded then inertia combined with a descent will result in the vehicle continuing at the same speed or even speeding up.

Matt

Creation Matt

Hello William B,

thank you for the suggestion!  I'll have a look when I've finished this reply.

The reason for the drive speeding up is because it is a motor vehicle (off-highway) and the engine speed is forced to neutral,  this does not necessarily mean that the vehicle  will slow down:  If the vehicle is loaded then inertia combined with a descent will result in the vehicle continuing at the same speed or even speeding up.

Matt

Matt, thanks for the feedback and the explanation. Good luck.

There are a lot ways to come in Rome.....

You can use a counter, reset that counter every second.

If the counter becomes to much counts (per sec) you stop the engine.