Monitor CMS2000 inverter via TCP/IP with USR-TCP232-E4 RS232/IP convertor

After months of waiting on hardware to arrive and playing around with different configurations, I have finally got my CMS2000 inverter to work through TCP/IP with POE.

RS232 to USB converter

The CMS2000 is a 2kW inverter with an RS232 connection for communications. If you simply want to view the data locally via a laptop, you will need a RS232 to USB adapter, specifically the Prolific USB-to-Serial Comm Port. Have a look at my review of RS232 to USB adapters for more info on the suitability of the converter.

RS232 to TCP/IP converter

Now, if you would rather run Ethernet to from the inverter and being able to read the values from any computer in your LAN, it is a little more complicated, but here is how.

The first thing you will need is a RS232 to TCP/IP converter, these can be purchased on eBay for about $25. Make sure you don’t simply get a serial to RJ45 cable, which are commonly used to configure managed switches. The model I received was the USR-TCP232-E45 by Jinan USR IOT Company China. The unit requires 5V power which I will discuss later.

The manual can be a little confusing, there is a test you can do if you have a com port or RS232 to USB adapter, where you basically create a loop and confirm it is all working. To get it talking to the CMS2000, configure the parameters of Port 0 (the RS232 port) as below. The main thing is to set it in TCP Server model. Configure the IP address and subnet as appropriate for your LAN.


The RS232 to TCP/IP converter takes 5V DC, now you can run a separate 5V line to the inverter which isn’t ideal or use a passive injector to inject 5V into the line and split it out at the inverter, this is not IEEE 802.3af compliant though.   If your switch supports PoE you can split the power out directly at the inverter with a TP-LINK PoE splitter model TL-POE10R. This can be purchased for $14, and even includes the power and Ethernet cables needed to connect to the USR-TCP232-E45.


To check the communications the CMS software ProControl can be used to check the communications prior to use with PVBeanCounter. Now, for some reason ProControl can’t connect directly via IP to the USR-TCP232-E45, fortunately I found a free virtual comm port software, which emulates a serial port connected to an IP address, the software is called VSP3 – Virtual Serial Port, developed by the HW group. Fairly easy to configure as below.

Final product

Review of generic USB to Serial (RS232) adaptors

Having purchased a number of generic USB to serial adaptors from eBay, I thought I would go over the pros and cons of the types available.

Prolific USB-to-Serial Comm Port (counterfeit)

Prolific USB-to-Serial Comm Port (counterfeit)

The least expensive of those found on eBay, apparently these have a counterfeit Prolific chip, which limits them to working only on Windows XP.

From Prolific;

Please be warned that counterfeit (fake) PL-2303HX (Chip Rev A) USB to Serial Controller ICs using Prolific’s trademark logo, brandname, and device drivers, were being sold in the China market. Counterfeit IC products show exactly the same outside chip markings but generally are of poor quality and causes Windows driver compatibility issues (Yellow Mark Error Code 10 in Device Manager). We issue this warning to all our customers and consumers to avoid confusion and false purchase.

As you can see on my Windows 7 machine I have the Code 10. I have had this cable working fine on a Windows XP machine though.

Prolific USB-to-Serial Comm Port (counterfeit) Device Manager

Prolific USB-to-Serial Comm Port (counterfeit) Code 10



With very similar packaging to the counterfeit Prolific above, and slightly more expensive, you can find these on eBay by search for Windows 7 compatible. These use the CH340 USB to serial IC and don’t have any problems installing on a Windows 7 machine. I have found that some serial devices do not like this adaptor, which made resulted in the purchase below.

USB-SERIAL CH340 Device Manager

Prolific USB-to-Serial Comm Port

Prolific USB-to-Serial Comm Port
Prolific USB-to-Serial Comm Port label

Possibly the real deal, and slightly more expensive then above. This Prolific PL2303 USB to serial adaptor has no problems installing on Windows 7, and my Solar Inverter which I was using to test, had no problems communicating unlike the above.  If you don’t want to waste time, get this adaptor, easily spotting with the black housing.

Prolific USB-to-Serial Comm Port Device Manager