How to connect Solid State relays to Masso TTL and spindle Outputs

[cncnutz]

Below are diagrams for three different scenarios of connecting Solid State Relays (SSR) to Masso outputs.

Please make sure you understand the risks and necessary precaution when working with Mains voltages. Always ensure that the power is off while working on it and that you obey all electrical regulations as required by your country. If in any doubt consult a qualified electrical engineer.

Solid State relays are broken up into 2 different types, AC & DC. This refers to the output side of the relay and what sort of load you will be connecting. If your load is a DC device eg a DC motor then you will need a DC Solid State Relay. If your load is an AC device eg an AC motor then an AC Solid State relay is required. The input side of the SSR needs to be optically isolated and able to be triggered by a 5 volt TTL signal from Masso. Masso TTL outputs can supply up to 5mA at 5v to the SSR. Most SSR's input are 3 to 32 volts so should work ok if the current draw is not too high. Please check your SSR input specification.

The Solid State relays shown in the drawings are there to show pin out only and are not an endorsement of the actual model relay itself.

The relays shown have one thing in common. Input is between terminals 3 & 4 with 3 being the positive and the output is between terminals 1 & 2. Ensure you consult the spec sheet of your SSR to get the correct terminals when wiring your Relay as they may differ between manufacturer and models. The output of the SSR can be thought of as a switch being closed when the SSR is triggered. Some SSR's have LED's on the input to show when they are triggered.

Solid State AC Relay - This connects between any TTL output and Masso GND. Connect the load on the output side of the SSR as you would a normal relay with a Normally open contact.

Solid State DC Relay - This connects between any TTL output and Masso GND. Connect the load on the output side of the SSR as you would a normal relay with a Normally open contact.

Solid State drive for Spindle control - This is connected through the spindle CW output as it provides additional protection. This circuit is intended for a Router, laminate trimmer or single phase AC motor used as spindle.

Cheers Peter

 

[halfstep]

Peter or anyone else. When the relay is switched off, there is still some current bleeding thru. I can plug in a light and when switched off, the light dims down. I get about 96v still coming thru. When I switch it on, I get 122v coming thru. It is an opto 22 120d10 3-32v relay. I have it wire according to you schematic above. I have it assigned to flood coolant and pin #9. When I click the flood coolant on and off, it goes bright when on and dim when off but doesn't go completely off. Any thoughts on why it doesn't go completely off?

 

[cncnutz]

@halfstep

Are you using an LED bulb or an incandescent bulb for your test. The SSR datasheet as I read it shows a 7ma leakage current when it is turned off which I envisage could light an LED light and you could also measure a high voltage at no load. Simply disconnecting the Masso output from the SSR terminals 3 & 4 would show if the Masso output is holding it on or not. If you disconnect Masso and the Lamp stays on then it is not Masso holding it on. Some LED bulbs have the name of Zombe bulbs because they light even when you turn them off because of stray capacitance.

Measuring the output side of the SSR doesn't really tell you anything that you don't already know. It is the input side of the SSR that will tell you what is going on.

What are the following voltage measurements?

With the SSR connected to Masso

• What is the voltage between terminals 3 & 4 of your SSR relay when the coolant is off?
  
• What is the voltage between terminals 3 & 4 of your SSR relay when the coolant is on?
  

Cheers Peter

 

[halfstep]

Thanks Peter.