The Maxiflex M1588 Single Channel Harwell¹ NIM is an Omniflex product designed to communicate with the Canberra (Harwell) range of radiological monitoring instruments, namely the AB96, iCAM and G64. The term ‘Single’ is used to indicate that the NIM has a single channel to differentiate it from dual serial port versions. The Harwell NIM is not available in a dual channel version.

The Canberra / Harwell AB96 monitor is an alpha / beta monitor, the iCAM is a newer Canberra offering which effectively replaces the AB96 whilst the G64 is a gamma monitor. A mixture of these monitor types can be accommodated by the NIM on the same network.

A typical system may consist of one or more Harwell NIMs each connected to one or more monitors. A multi-drop, 2 or 3 wire RS485 network is used to connect the NIM (Host) to the monitors (Slaves).

All data is accessible by a SCADA, DCS or PLC via the Maxiflex system CPU through a 4000 register Data Interchange Table.

All system configuration data and dynamic data can be read and written through this convenient table interface.

In addition, the Harwell NIM can support the development of ‘special’ applications in EziFORTH programming language although this is not the norm. Custom code may be downloaded to the module to communicate with any device equipped with a RS232 or RS485 serial port.

Using the supplied Omniset configuration utility, advanced polling schemes may be easily set up without the need for programming. All polling and communications processing is performed in the module, unloading the Maxiflex CPU module for the more important system tasks such as control and SCADA communications.

¹ Harwell was the original name of the company Canberra. As some of the older instruments are still tagged ‘Harwell’ and for historical reasons this module is still referred to as the ‘Harwell NIM’.