If your building this circuit for a learning project then that is great ignore the rest of this post.
Buy an old Allen Bradley SLC 150 with a hand held programmer. The 24 VDC version is designed for reed switches. These were $500 brand new 20 years ago. Many sellers think because you can not buy these anymore they are worth their weight in Gold so check prices there are still some sellers selling them at a reasonable price. 10 years ago these were selling for $20 each used. It has been 8 years since I worked with these I believe Series C is the unit you want. You do not need an expander unless 20 inputs and 10 outputs are not enough. The expander will double the inputs and outputs. The 24 volt DC unit needs a 24 VDC Allen Bradley power supply. The 24 VDC power supply was nothing special you can build one with a transformer, bridge rectifier, and 1 large capacitors.
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This is optional it allows you to change the time on the timer circuits as your machine is running without the need for reprogramming with the hand held programmer. Very handy and fast.
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The SLC 150 comes with a battery that keeps the EEprom from loosing memory when the unit is turned off. If you buy a used unit be sure to ask if the battery is good and how old the battery is. Batteries use to be $30 I use to cut the wire from the old batteries and solder on a new $5 rechargable battery that I bought from the local hobby shop. Battery life is 8 years.
**broken link removed**
Buy an old Allen Bradley SLC 150 with a hand held programmer. The 24 VDC version is designed for reed switches. These were $500 brand new 20 years ago. Many sellers think because you can not buy these anymore they are worth their weight in Gold so check prices there are still some sellers selling them at a reasonable price. 10 years ago these were selling for $20 each used. It has been 8 years since I worked with these I believe Series C is the unit you want. You do not need an expander unless 20 inputs and 10 outputs are not enough. The expander will double the inputs and outputs. The 24 volt DC unit needs a 24 VDC Allen Bradley power supply. The 24 VDC power supply was nothing special you can build one with a transformer, bridge rectifier, and 1 large capacitors.
**broken link removed**
**broken link removed**
This is optional it allows you to change the time on the timer circuits as your machine is running without the need for reprogramming with the hand held programmer. Very handy and fast.
**broken link removed**
The SLC 150 comes with a battery that keeps the EEprom from loosing memory when the unit is turned off. If you buy a used unit be sure to ask if the battery is good and how old the battery is. Batteries use to be $30 I use to cut the wire from the old batteries and solder on a new $5 rechargable battery that I bought from the local hobby shop. Battery life is 8 years.
**broken link removed**
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