https://github.com/fescron/2ch-4-20ma-converter
1/2 channel 4-20 mA to voltage converter boards using LMP8640 current sense monitor.
https://github.com/fescron/2ch-4-20ma-converter
4-20ma breakout-board cern-ohl current-loop current-shunt-monitor dramco ina196 isoladed kicad kicad-breakout-board kicad-schematics kuleuven lmp8640 opamp oshw phoenix-contact tec2-0913 texas-instruments traco-power
Last synced: 5 months ago
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1/2 channel 4-20 mA to voltage converter boards using LMP8640 current sense monitor.
- Host: GitHub
- URL: https://github.com/fescron/2ch-4-20ma-converter
- Owner: Fescron
- Created: 2019-11-23T23:29:59.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2021-10-15T10:39:09.000Z (over 4 years ago)
- Last Synced: 2023-11-27T19:54:46.927Z (over 2 years ago)
- Topics: 4-20ma, breakout-board, cern-ohl, current-loop, current-shunt-monitor, dramco, ina196, isoladed, kicad, kicad-breakout-board, kicad-schematics, kuleuven, lmp8640, opamp, oshw, phoenix-contact, tec2-0913, texas-instruments, traco-power
- Homepage:
- Size: 3.65 MB
- Stars: 6
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# 2ch-4-20mA-converter
This board converts two *4 - 20 mA* signals to a voltage using a `LMP8640` *Current Shunt Monitor* from *Texas Instruments*. To provide power to the *4 - 20 mA* sensors a `TEC2-0913` 2W 15V Isolated DC-DC converter is used from *Traco Power*. Quick-connect terminals from *Phoenix Contact* are also used.
To allow for extensive testing three separate GND nets/planes and a lot of test points are used. They can be connected together using jumpers if necessary. The power supply can also be disabled and fully disconnected from the sensors using a jumper as well (wich can also be used to measure the in-line current given to the whole sensor circuit).
- Click [here](hardware/2ch-4-20mA/2ch-4-20mA.pdf) to go to the **schematic**.
## LMP8640 vs INA196
A lot of designs still use the `INA196` *Current Shunt Monitor* from *Texas Instruments*. In the picture below is a comparison between the `LMP8640` and the `INA196`. No real disadvantage was found to not use the `LMP8640`.
## BOM
| Component | Value | Footprint | Other | Ordering |
| ------------ | -------------------- | ------------- | ------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------- |
| U1, U2 | LMP8640 | SOT-23-Thin-6 | Texas Instruments Current Shunt Monitor | [Mouser.be](https://www.mouser.be/ProductDetail/Texas-Instruments/LMP8640MK-T-NOPB?qs=sGAEpiMZZMvEn2pkGav3bPb6jlX9oNVbBBSIeXfzDzM%3D) |
| U3 | TEC2-0913 | SIP-8 | Traco Power 2W 15V Isolated DC-DC converter | [Mouser.be](https://www.mouser.be/ProductDetail/TRACO-Power/TEC-2-0913?qs=sGAEpiMZZMvGsmoEFRKS8Koqt8Pjkl39l4aaKfuLyMgVYp%252Bicpvd3A%3D%3D) |
| C1, C2 | 100 nF = 0,1 µF | 0805 | X7R, 16V, 10% | [Mouser.be](https://www.mouser.be/ProductDetail/Yageo/CC0805KRX7R7BB104?qs=sGAEpiMZZMs0AnBnWHyRQMMzfhmH8IQX2eB5GrOHrwc%3D) |
| R1, R2 | 6,2 Ω | 0805 | 0,1% | [Mouser.be](https://www.mouser.be/ProductDetail/TE-Connectivity-Neohm/CPF0805B6R2E1?qs=sGAEpiMZZMu61qfTUdNhGxAfPTOoMd3Mys3VDWDGxkc%3D) |
| R1, R2 (alt) | 4,99 Ω | 0805 | 0,1% | [Mouser.be](https://www.mouser.be/ProductDetail/TE-Connectivity-Neohm/CPF0805B4R99E1?qs=sGAEpiMZZMu61qfTUdNhGxAfPTOoMd3MWO8ubRKmtsI%3D) |
| J1, J2 | PTSA_1,5/_2-3,5-Z_BK | Pitch: 3,5 mm | 2 contacts @ 45° (20-16 AWG), 250V 2A | [Mouser.be](https://www.mouser.be/ProductDetail/Phoenix-Contact/1751765?qs=sGAEpiMZZMvZTcaMAxB2AOnzhHajZlLEGRULH%2FxUGnk%3D) |
## UPDATE 03/2020 - 1 CH board without power supply
To better conduct tests with the `LMP8640` chip a simple 1-CH board was layed out without a power supply and etched on a single sided board.
- Click [here](hardware/1ch-4-20mA/Plots/1ch-4-20mA.pdf) to go to the **schematic**.
- Click [here](hardware/1ch-4-20mA/Plots/1ch-4-20mA-F_Cu.pdf) to go to the **board layout** (mirrored).