Measurement and control systems for laboratory power supplies
All Aim-TTi laboratory power supplies offer high accuracy digital meters together with high resolution controls and DC output switches. All models now include switchable remote sense terminals.
DISCONTINUED: Standard models, such as the EL and EX series, incorporated three digit meters for both voltage and current. This provided a level of accuracy and resolution sufficient for many purposes.
Separate coarse and fine voltage controls allowed rapid and precise adjustment whilst a semi-logarithmic current control provides increased setting resolution at lower currents. These models did not have remote sense.
Precision models, such as the EL-R EX-R, PL, TS, TSX and CPX series, offer a higher level of precision by incorporating four digit meters and remote sense terminals.
Four digit meters provide higher resolution and accuracy. Remote sense enables the power supply to regulate the voltage directly at the load thus eliminating the effect of connection lead resistance.
High Precision models
The QL series offer a further level of precision by incorporating 16-bit digital control and five digit metering with a resolution of 1mV. This is matched with 0.1mA current resolution and remote sense terminals.
Voltage and current can be set directly from a numeric keyboard or can be set in quasi-analogue mode using a rotary encoder. A similar control system is used on the high power QPX series.
Remote Sense - do you really need it ?When you need to buy a general purpose dc power supply, there are a bewildering number of manufacturers to choose from. When you read the specifications they all look much the same. Most quote load regulation figures of around 0.01%. Some quote a volt meter accuracy better than your DMM.
In practice, however, these figures can be almost meaningless if they omit the essential feature needed to achieve high accuracy and good load regulation - remote sensing. Even the best known names in the business omit remote sense from their lower cost power supplies - so does it really matter ?
So do you really need it?Well it depends upon your application. If you're working at very low currents then probably not. If you don't need to know the voltage at the load accurately, then possibly not.
What may not be obvious is how poorly regulated and inaccurate a power supply without remote sense can become: A two metre length of a 24/0.2 wire pair has a resistance of around 0.1 Ohms. For a 5V load drawing 3A the metering error without remote sense would be 0.3V with an effective full current load regulation of 6%. It makes a nonsense of specifications such as 0.01%.
All Aim-TTi power supplies have remote sense capability. You can choose local or remote sense at the flick of a switch - so if you don't need it, you don't have to use it.