Model 420 Features
The AMI Model 420 Digital Programmer is a sophisticated power supply controller which allows an operator to manage a superconducting magnet system with unprecedented accuracy and ease of use. The Model 420 is the heart of a modern superconducting magnet system; when it is used in conjunction with a four-quadrant power supply, it provides for a degree of flexibility and accuracy previously unavailable in an economical commercial product.
Digitally-Controlled
The Model 420 is managed by a microcomputer-based controller which controls all analog data conversion, display/keypad functions, communications I/O, analog programming signals for the external power supply, and all control law computations. The Model 420 also incorporates digital signal processing (DSP) functions that provide for accurate control, low drift, and flexibility for a wide range of applications.
Superior Resolution and Stability
The Model 420 Programmer utilizes 20-bit converters to translate signals between the analog and digital domains. Precision instrumentation techniques and potentiometer-free designs are employed throughout the instrument to ensure accurate signal translation for a wide range of conditions. All pause and hold functions are performed in the digital domain which provides for excellent stability and low drift (<0.01%) of the programmed magnetic field.
Intuitive Human-Interface Design
The Model 420 Programmer was designed so as to simplify the interface where possible. All functions were analyzed and subsequently programmed so that the most commonly used functions are accessible via the least number of keystrokes. The menus are also presented in a logical fashion so that the operation of the Model 420 is intuitive to the user.
The provision of a velocity-sensitive rotary encoder on the front panel also allows the operator to fine-adjust many of the operating parameters of the magnet system. Operating current can be controlled to 15-digit resolution (double-precision floating point used for internal storage).
Flexible Operation
The Model 420 Programmer is engineered to be compatible with many magnet power supplies. From simple single-quadrant supplies, to more elaborate four-quadrant units, the Model 420 is user-configurable such that the operational paradigm complies with a specific power supply system.
The Model 420 Programmer is available in five standard configurations: ± 10 A, ± 100 A, ± 200 A, ± 300 A. Configurations of 300 A and below use internal current-measuring shunts. The ± 10 A configuration is designed for applications that require high-resolution magnet current and ramping controls for applications such as ADR.
Remote Interfaces and LabVIEW-Compatible Drivers are Standard
The Model 420 Programmer provides an RS-232 (or optional RS-422) serial port and a GPIB port (IEEE 488.2 compliant) as standard features. In contrast to other magnet power supply system designs, an expensive and complex additional analog-to-digital conversion system is not required to collect data via a host computer. Most settings can be controlled via the remote interfaces and the front panel can be remotely locked to prevent accidental operation. The Model 420 also provides trigger functions for data collection and/or logging during operation.
LabVIEW-compatible drivers are included with the Model 420 and provide an integrated environment for magnet system monitoring and control (see image below). The collection includes GPIB drivers and integrated panel examples for the Model 420 Digital Power Supply Programmer, Model 135 Liquid Helium Level Monitor, and the Neocera Model LTC-21 Temperature Controller.
Click for a full size 1024x768 version of the image.
Programmable Safety Features
The Model 420 Programmer is designed to allow the operator to program the system from the front panel, or remotely, with current and voltage limit parameters which will not be exceeded during operation of the system. Once set, should an operator inadvertently attempt to operate beyond the specified limits, the programmer will not accept the parameter and audibly beep. An appropriate error message is available via the remote interface. The Model 420 Programmer also automatically limits the charge rate of the magnet to the specified voltage limit.
Please contact an AMI Sales Representative for more detailed information including compatible power supplies, function descriptions, communication command set, system diagrams, etc. A complete electronic copy of the manual is also provided below. Customers are encouraged to review the manual as a pre-sales resource.
Rev. 7 Model 420 manual in Adobe Acrobat 3.0 format (model420.pdf, 1.8 MB)
Back to Superconducting Magnet
Systems page
AMI HomePage |
Sales | Superconducting
Magnets | Liquid Level Instrumentation
Technical Support | Customer
Services | AMI Picturebook | E-Mail AMI
