Re: MB2 ESS relay connection
Did you remember to add the flyback diode to the relay coil? If not, you may have fried the optocoupler.
Re: MB2 ESS relay connection
A relay coil is an inductive load. When you switch off an inductive load, there is a large voltage spike that can (and does) destroy sensitive electronic elements such as transistors.
Whenever you control a relay with a transistor (or an optocoupler, which contains a transistor), you must shunt the relay coil with a diode. The diode dissipates the back EMF and prevents the voltage from spiking to dangerous levels.
The MB2 manual mentions the diode on page 14: http://www.cncroom.com/downloads/MB2...al%20E16R5.pdf
Re: MB2 ESS relay connection
If you need a suggested part, 1N4007 is the popular one.
Al.
Re: MB2 ESS relay connection
Thought about using one of the relay contacts on your VFD instead?
Re: MB2 ESS relay connection
Quote:
Originally Posted by
Sterob
Thought about using one of the relay contacts on your VFD instead?
That is a good idea. (Most) VFDs have one or two relays that can be programmed for different functions, such as "Alarm", "Spindle rotating", "Spindle at speed" and so on.
Depending on the current rating of the pump, you may connect the pump directly to the VFD, or use an external relay.
Re: MB2 ESS relay connection
It is always advisable to use an external relay or operator, if you overload and damage the internal relay, it is costlier to fix!
Al.
Re: MB2 ESS relay connection
Quote:
Originally Posted by
Al_The_Man
If you need a suggested part, 1N4007 is the popular one.
Al.
Thanks Al
I have a curious situation going on..;l
I bought one of these
https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1
After the advice yesterday - i think it should be ok for the task.... i have set the y305 output to come on when i activate the spindle (for the pump) and though i see the output light on/off when commanded, the relay state does not change...
For learning and incase i wanted extra i also purchased this
https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1
If i wire this up it is the same behavior... and i was curious though the 'input side' only has to COM terminals, and its says pnp/npn input, am i right in thinking that 24V to the COM?
Whichever is correct i can not get any change of signal lights on the relay or optocoupler board even though the MB2 light is active on/off....
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Re: MB2 ESS relay connection
IIRC, the MB2 states a sinking opto output, if using it with a external relay board that has opto input, the recieving opto has to be set to sourcing input.
Al.
Re: MB2 ESS relay connection
I would read it that way, see if it works, it should not cause any problems either way, just only one way will work.
Al.