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I-Introduction
The RBL488 series is a box for control the charge from the sources, for example battery we can control the current and the power, if we want 20A from the battery for example we put in the RBL constant current mode equal to 20, the same for the power, for us this is the important use of charge box here but in general, The RBL488 series single channel loads are ideal for testing power supplies, fuel cells, large batteries, and other related DC power equipment. The high range current capability and constant power feature facilitate battery testing and analysis, this is the important part of our work.
For this, our goal is to create interface of RBL with LabView, than from this interface we can lunch the test.
Figure 1 RBL488 series
II-Connection PC (LabView) and RBL488 series
Normally, the connection between PC and RBL488 is series, but we use in this project connection NI GPIB-USB-HS completely IEEE488.2 compatibility.
Figure 2 NI GPIB-USB-HS
The compact NI GPIB-USB-HS transforms any computer with a USB port into a full-function, IEEE 488.2 controller that can control up to 14 programmable GPIB instruments.
This controller is easy to install and use because there are no external DIP switches and you do not need to restart our computer for the system to recognize your IEEE 488.2 interface. With the GPIB-USB-HS, we can get up and running quickly, so we can focus on developing our instrument control applications.
From the LabView interface to write inside the cable we use the block “Visa Write” and for read we use “Visa Read” as we can see in figure 3
III-Parameters to control and limits
As we say in the introduction, they are many modes to use RBL488 series: Constant Current, Constant Resistance, Constant Power, Constant Voltage and Pulse mode, but in this project we are interested to control two parameters: constant Current and constant Power.
Than to control constant current from LabView we should write “CI<number>” and “CP<number>” for the constant power, these two command are string and we add the value by concatenate string as we see in figure 3.
Figure 3 LabView blocks
In other side, we have two limits for the constant current and constant power, as we program the command of the two parameters (“IL<number>” and “PL<number>” for the current and power respectively) we put a constant variable not accessible by the user and we define the limits of the two parameters, as we can see in figure.
Figure 4 Limits Blocks
IV-LabView interface for RBL488
The goal of our work is to create a user interface easy to use by the client or the tester, in this part we will speak about the interface and the method of work.
First the “Visa resource name”, we should select the port correspond to our cable interface (NI GPIB-USB-HS).
Second the Short Circuit: this command is used to apply or remove a simulated short circuit from the device, if the load draws more than its rated current it can be damaged, only use this command if you are sure the maximum current of the load will not be exceeded, for this we use the command “SHORT OFF” or “SHORT ON” as we can see in the figure 4.
Figure 5 Blocks of Short Circuit
In figure 5, we see how to select our mode of work: Manuel or Automatic, in LabView we make this by use Case structure.
Figure 6 Select Mode of work
In figure 6, we can select Constant Current or Constant Power.
Figure 7 Select Mode of Consign
As normal, if we select the Manuel mode, than we change the value every time we need. In the Automatic Mode, first we select the path of excel or TXT folder for the numeric value of the Constant Current or Power, but we will specify the file (.txt) for our work and we see two block display the time and the correspond value of mode select (Figure 7).