Hi everyone.
My project is about finding a way for an Arduino Uno to communicate and interface with a
Bird RF 4421 Power Meter.
However, after reading the manual and data sheet of the power meter, I still couldn't figure out how to connect the pins on the back of the power meter to an Arduino Uno board. I'm just a beginner and could not really understand the terms and the jargon inside the user manual.
I'm only familiar with connecting motors, voltage meters etc to an Arduino since they already have a basic voltage reading where the Arduino can easily recognize.
However, this power meter has multiple pins to connect and I'm not sure how do I obtain values from the power meter through Arduino. In short, I need to obtain power reading measurements from the power meter through Arduino. Note that I do not need to control the power meter in any way, just have to get the power readings.
Any help is really appreciated. Hope my post does not seem trivial or dumb 
Here is the official link to the Bird RF 4421 Power Meter: 404
A picture:
The exact model I'm using: eBay research tools | Seller Center
The meter has a standard 25 pin D type RS232 output, which for Arduino requires the use of an RS232 to TTL level adapter, like this one and likely, a 25 pin to 9 pin adapter cable.
The communications protocol is described in the manual and it is not simple. Before attempting to write an Arduino program to implement it, you should experiment using a terminal program and a PC, until you completely understand how it is supposed to work.
Thank you for your reply. After taking a quick look at the back, there are 2 ports which can be used. Some people have suggested that the bottom right port is easier to be used. I believe this is the RS232 you are talking about. I will try to research more about it.
The manual clearly identifies the RS232 port on page 2. It will be your best friend.
Hello,
Is it possible to show a simple Arduino program that reads/controls the power meter to act as a stepping stone for me? Eg. How the commands in the manual can be used in Arduino. If its too much of a hassle for you, then ignore this message Your help is greatly appreciated
So far my progress is this. The port at the back should be connected to a 25 to 9 pin converter. Then another converter (picture below)
is used before connecting to the Arduino. So what I assume now is that the Arduino will be receiving a 0-5V input that represents the data sent by the power meter and the Arduino will also be able to somehow control the power meter through another wire? (the blue and green wires in the picture).
On the programming side, what I've figured is that I have to put the commands in a string. For example: “PNFCFDT3TRG”. This string sets up the 4421 to send no prefixes, read forward dBm, make one reading on “TRG”, and triggers a measurement. But in Arduino, I have to convert these letters into HEX like this following command:
#include <SoftwareSerial.h>
SoftwareSerial mySerial(10, 11);
byte GetData[] = {0x02,0x46,0x46,0x48,0x44,0x34,0x04};
mySerial.write(GetData);
So GetData will have the instructions and will be sent to the power meter once Serial.write is performed.
Am I on the right track so far?
