DC calibrator combines precision performance and ease of use

Intuitive operation is aided by the provision of dials for each digit and switch and a clear display using traditional 7-segment LEDs.

The instrument is the successor to Yokogawa's earlier 2553 model, but offers higher performance in terms of range and accuracy, additional temperature measurement options, resistance generation, and a choice of communications interfaces as well as being much lighter. The 2553A can be used with existing 2553 programs, allowing its integration in a system containing a mixture of 2553As and 2553s.

The heart of the instrument is a DC current/voltage generator with five voltage ranges from 10 mV to 30 V, four current ranges from 1 mA to 100 mA, ten different types of thermocouple (as specified in IEC standards) as well as Pt100 RTDs (resistive temperature detectors), and a 400-ohm resistance generation range.

By setting temperature value, the instrument generates thermocouple electromotive power and can therefore be used to calibrate temperature controllers. It also generates temperature-related resistance values for RTD measurements. Settings can be made by resistance value as well as temperature, making it possible to calibrate using the resistance value.

It also offers RJC (reference junction compensation) at the output terminals, with a choice of three modes: internal, external and manual.

User defined temperature calibration can be achieved by copying text files including relationship parameters between temperature and voltage or between temperature and resistance, allowing calibration curves to be generated for various types of thermocouple and RTD.

Text files can be easily created by text editor or Excel on a PC. Files can be easily transferred by "drag & drop" operations when the instrument is connected to a PC via a USB cable, enabling the PC to recognise the 2553A's internal memory as a mass storage drive.

The instrument can also be used to calibrate sensor transformers and transmitters for pressure, volume flow and temperature as well as environmental parameters such as pH, ORP (oxidation reduction potential), conductivity or dissolved oxygen. It can also simulate 2-wire transmitters for 4-20 mA signals.

It measures 132(H) x 213(W) x 300(D) mm, and weighs approximately 3 kg. It comes complete with USB, Ethernet and GP-IB communication interfaces.