I`m currently making some proto circuits and I would love some feed back/Ideas etc.
All these circuits will connect to Arduino or Arduino compatible devices.
Anyone have time to help out with some reviews?
First circuit is a 4-20ma board
I`m currently making some proto circuits and I would love some feed back/Ideas etc.
All these circuits will connect to Arduino or Arduino compatible devices.
Anyone have time to help out with some reviews?
First circuit is a 4-20ma board
Does these look right. At 12VDC I used a 16VDC TVS @ 5VDC I used an 8VDC unit
8VDC (Voltage - Reverse Standoff (Typ)
12VDC Voltage - Reverse Standoff (Typ)
I didn't add the terminator this model is designed to always be the Master. I will add this to the other slave model.
I added the 10ohm 1w resistor as an energy adsorbing resistor, always on the receiving side of the TVS
Does these look right. At 12VDC I used a 16VDC TVS @ 5VDC I used an 8VDC unit
8VDC (Voltage - Reverse Standoff (Typ)
12VDC Voltage - Reverse Standoff (Typ)
I didn't add the terminator this model is designed to always be the Master. I will add this to the other slave model.
I added the 10ohm 1w resistor as an energy adsorbing resistor, always on the receiving side of the TVS
Tom,
This is a little more like what I was talking about:
This provides line to line and either line to rail protection. These are bi-directional transzorbs, voltages should be in the VCC range (or slightly less). The resistor, while normally a good idea, might not be the best way to go with a RS485 transceiver as would imbalance the signal a bit (depending on the terminator value). The transzorbs are a nice touch, but I know many people do without them and their designs still work. This is more of a protection against static discharge and gross mis-wiring.
Gene
