The microprocessor controlled loads of the series EA-EL 3000 (400W) and EA-EL 9000 (2400W - 7200W) accomplish nearly all requirements in modern load concepts for industrial and R&D areas. The four common regulation modes constant voltage (CV), constant current (CC), constant power (CP) and constant resistance (CR) can be used in any combination with the three operation modes A, B and A/B.

A or B operation:
Two different set values for all operation modes preselectable and switchable (manually or externally via a trigger input at the analogue interface).

A/B operation:
Automatic alternation between two set values A and (corresponds to a square wave control), seperately adjustable in the chosen operation mode (CC, CV, CR oder CP). The pulse widths of both, A nd B, are also seperately adjustable from 50us...100s. This corresponds to a frequency range of 10kHz...0,005Hz. Furthermore, the rise and fall time of the alternation from A to B or B to A is adjustable from 30us...200ms. The resulting square signal is led out as a trigger signal (only EL3000) to external applications (see 'Trigger output' below). An example figure:

 

 

The next example figure shows the internal/external trigger signal with modified rise time. If a voltage source is connected to the load, it will be loaded with an current which alternates, in Constant Current mode, between two values (A and B) at a certain frequency f, determined by the total pulse width. The dynamic A/B operation can also be controlled by an external, user-defined, square wave shaped trigger signal, that is fed into the analogue interface. The setting for the rise time will remain effective here.

 

Battery test mode:
This is used for a controlled discharge of various battery types, with Ampere hourse (Ah) count, undervoltage shutdown, as well as elapsed time display in the three operation modes CC, CP and CR. The set value for the chosen operation is also adjustable here.

Display:
All necessary actual and set values are displayed at once and clearly viewable on a backlit, blue-white, two-line dot display.

Analogue interface:
Here are set value inputs for U/I/P/R, monitoring outputs for U & I, control inputs (Remote on/off, switching the resistance range, switching resistance mode on/off), signalling output for errors (OT/OVP) and a trigger input (external switching between A and B) available.

Trigger output (only EL 3000):
The internal trigger signal is led out here. This output is located on the rear. It may be used for testing purposed or to synchronise with other applications.

 

System Bus terminal (only EL 9000):
This additional terminal provides the possibility of running the load(s) in a two-quadrants operation in combination with compatible power supplies (series PS 9000, PS 8000 DT/2U, PSI 8000 DT/2U and PSI 9000). Furthermore, the internal regulation speed can be switched from normal to fast here.

 

Card slot:
For optionally equippable interface cards, which are used to control the load with a PC and to implement it into existing networks, like CAN. LabView support through ready-to-use VIs. Following cards are supported: USB, CAN, RS232, CAN, GPIB/IEEE and Ethernet/LAN. Since the firmware version 3.01 the USB, RS232 and CAN card allow full remote control of the load. With the IEEE and Ethernet/LAN cards the user can control and set all relevant set values and status by SCPI commands.

 

Options:

• Retrofittable, digital interface cards for RS232, USB, CAN, GPIB, Ethernet/LAN
• Water cooling (only EL 9000)