20 ma isolation – Ocean Optics NeoFox User Manual

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C: Analog Output

013-20000-009-02-201203

 Mounting both devices on a common metal surface (such as a DIN rail)
 Connecting both devices to a single computer or USB hub
 Using the same measurement device to measure the 0-5V output and the 4-20mA output. (The 0-

5V output is referenced to the NeoFox circuit ground.)

 Using the same measurement device to communicate with NeoFox via RS232 and to measure the

output of the 4-20 mA output. (RS232 is only available in NeoFox GT models with an F or
greater in the third digit of its serial number, which are available by request).

Users should be aware of any possible connections between NeoFox and their interface circuits
when setting up their hardware.

4-20 mA Isolation

Some users (especially those in industrial settings) may need to use an isolated 4-20 mA loop.
Unfortunately, the current sink on the NeoFox unit is not isolated and is not suitable for use in
environments which may cause the loop voltage to exceed 30V. However, there are a number of third-
party products available that can convert the output of the NeoFox into an isolated 4-20 mA loop
transmitter.

Some suitable products include:

 LPI-1

 Manufacturer: A Pi (

http://www.api-usa.com

)

 Suggested Vendor: Mod-tronic. (

http://www.mod-tronic.com

)

 Part Number: LPI-1
 Datasheet:

http://www.api-usa.com/pdf/api/api_lpi-1_lpi-2.pdf

 931S-A1A1N-IP1

 Manufacturer: Rockwell Automation
 Suggested Vendor: Varies by geographic region
 Part Number: 931S-A1A1N-IP1
 Datasheet: