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With effect from September 2022 the GWDMX lighting controllers are no longer available; manufacture of both versions, the hand-held GWDMX and the wall mounted GWDMX-W has ceased.

With effect from 1st July 2021 Greenwich Instruments Ltd has ceased trading; all orders for Greenwich Instrument products will be processed by Cephos Electronic Circuits Ltd. The new Company details can be found on our ‘Contact’ page in the above menu.

Non Volatile RAM

Manufactured in the UK

What is NVRAM?

NVRAM is ‘Non-Volatile Random Access Memory.’ It is a type of Random Access Memory that retains data after the host device’s power is turned off or has suffered an inadvertent power loss.

The Greenwich Instruments NVRAM devices retain critical data, at this point of power failure, by using an alternative source of power in the form of its self-contained, internal, lithium battery. This Non-volatile Static RAM is often used to store computer hardware settings or data that needs to be maintained when the computer is shut down.

Power down is very fast, essential for data integrity. The power down circuit is referenced and triggered at 4.5V. Data is retained in less than 15microseconds, much faster than power failure conditions.

Greenwich Instruments NVRAM

Greenwich Instruments NVRAM is manufactured in JEDEC standard DIL (Dual In-Line) packages.

The 16k GR281 is in a 24pin dil package, the 64k GR881 and the 256k GR3281 are in 28pin dil packages

The 1M GR12883 (in a 32pin dil package) is no longer manufactured

NVRAM Applications

When powered down, these devices are transportable and data can be moved from system to system. They are pin-compatible with standard EPROMS, ideal for program development, data collection in dataloggers, program changes in process control, robotics and user-defined lookup tables.

GR281

The GR281 is a 2048 word by 8 bits (2k x 8) non-volatile static RAM fabricated from advanced silicon gate CMOS technology and a high reliability lithium power cell.

The 24W dil pinout of the GR281 conforms to the JEDEC standards and is fully compatible with normal static RAM

Greenwich Instruments GR881 Non Volatile RAM

GR881

The GR881 is a 8192 word by 8 bits (8k x 8) non-volatile static RAM fabricated from advanced silicon gate CMOS technology and a high reliability lithium power cell.

The 28W dil pinout of the GR881 conforms to the JEDEC standards and is fully compatible with normal static RAM

GR3281

The GR3281 is a 32768 word by 8 bits (32k x 8) non-volatile static RAM fabricated from advanced silicon gate CMOS technology and a high reliability lithium power cell.

The 28W dil pinout of the GR3281 conforms to the JEDEC standards and is fully compatible with normal static RAM

GSM2 Stepper Motor Driver

Manufactured in the UK

GSM2 Product details

The GSM2 is a standalone drive board designed to drive a stepper motor in unipolar mode. It is done either with or without forcing resistors connected between motor commons and supply voltage.

When using the logic connections, you are able to select full, half or wave mode and direction and speed external clock. The GSM2 drive board allows an enable and disable input for various start/stop control options. The stepper motor used with the board must also have four phases and five, six or eight wires.

Compatible with any four phase unipolar stepper motors up to 2A/40Vdc per phase with full, half and wave modes able to be selected.

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