Purely overall and generally speaking part of my life on a daily basis is measuring current, voltage, pressure, delta pressure, temperature, flow, force and a host of other engineering units. Most of this data is provided by transducers of one flavor or another.
Now a few post back CafeLogic posted in part:
Anymore, this is something I live by and not just for current sense amplifiers but just about soup to nuts. A good example pertaining to temperature is in the attached images.
Left to right is an old Minco Temperature Transmitter. This unit is designed for a J thermocouple and has a range of 35 F to 700 F and with a single 24 VDC supply outputs 4 to 20 mA that I can run through a 250Ω or 500Ω resistor and get 1 to 5 Volts or 2 to 10 Volts to pass to an A/D converter. Very easily scaled and linear. Those units are at least 10 years old. Next left to right is another similar unit, made by INOR in Sweden. These are a newer version but pretty cool devices as they are user programmable for TC type, range plus additional features as well as RTDs. Free software and a PC with a serial port does it all. That center image is about 5 or6 years old. The unit on the far right is real nice. Fully programmable using RS232 or USB for mV inputs as well as TC inputs in all flavors. Isolated input as well as differential input. For example if I have a 10 Amp shunt where 0 to 10 Amps = 0 to 50 or 100 mV I can program it so 0 to 10 Amps = 4 to 20 mA and scale whatever I want.
The cost? The first unit at the time (10 years ago) was about $100 USD. The new unit on the right that does it all and fully programmable? About $70 USD. Now granted that $70 is a chunk of change but...
The work is done. If I start with a chip I need to make a board. Many chips for temperature (as an example) really need careful board design. Then board fabrication and so on.
Now what to do with my signal. I have an analog voltage or current (nice and linear) to my engineering units being measured. Yes, I can use a PIC but all I want is an A/D converter. Again, I like commercial turn key stuff. The little starter kits on this page are a good example. The DI 194 is a good deal but only RS232, the DI 148 and 158 are nice and the 158 offers differential isolated inputs. Ideal for current shunts. They come with nice software also.
Anyway, just my take on some of this stuff and dinner is ready.
Ron
Now a few post back CafeLogic posted in part:
Anymore, this is something I live by and not just for current sense amplifiers but just about soup to nuts. A good example pertaining to temperature is in the attached images.
Left to right is an old Minco Temperature Transmitter. This unit is designed for a J thermocouple and has a range of 35 F to 700 F and with a single 24 VDC supply outputs 4 to 20 mA that I can run through a 250Ω or 500Ω resistor and get 1 to 5 Volts or 2 to 10 Volts to pass to an A/D converter. Very easily scaled and linear. Those units are at least 10 years old. Next left to right is another similar unit, made by INOR in Sweden. These are a newer version but pretty cool devices as they are user programmable for TC type, range plus additional features as well as RTDs. Free software and a PC with a serial port does it all. That center image is about 5 or6 years old. The unit on the far right is real nice. Fully programmable using RS232 or USB for mV inputs as well as TC inputs in all flavors. Isolated input as well as differential input. For example if I have a 10 Amp shunt where 0 to 10 Amps = 0 to 50 or 100 mV I can program it so 0 to 10 Amps = 4 to 20 mA and scale whatever I want.
The cost? The first unit at the time (10 years ago) was about $100 USD. The new unit on the right that does it all and fully programmable? About $70 USD. Now granted that $70 is a chunk of change but...
The work is done. If I start with a chip I need to make a board. Many chips for temperature (as an example) really need careful board design. Then board fabrication and so on.
Now what to do with my signal. I have an analog voltage or current (nice and linear) to my engineering units being measured. Yes, I can use a PIC but all I want is an A/D converter. Again, I like commercial turn key stuff. The little starter kits on this page are a good example. The DI 194 is a good deal but only RS232, the DI 148 and 158 are nice and the 158 offers differential isolated inputs. Ideal for current shunts. They come with nice software also.
Anyway, just my take on some of this stuff and dinner is ready.
Ron
