New 8-Channel cryogenic temperature monitors with RS-232 interface

A cost-effective 8-Channel Cryogenic Temperature monitor has been successfully developed and tested at IUAC. This is an 8-channel low-temperature device (4K to 350K) with multi-sensor support. These are recently developed for building a new distributed 40-channel Linac thermometer application at IUAC. Each one of the 8 channels of this device can be independently set anytime as a Temperature or Resistance or Voltage (TRV) channel through a front-panel keypad. It also offers various features like an RS-232 interface, menu-driven keypad, flash storage, multi-sensor calibration curves, implementation of custom lookup tables through a numeric keypad, a VFD display, and 8 fast voltage outputs and distributed connectivity directly to the Cryogenics control room which is nearly 50 meters away. Each channel has 3 independent current sources (a total of 24, programmable from 10 microamperes to 10mA) that can be configured to study self-heat effects for a variety of sensor calibration applications. The low-temperature measurement, which ranges from 4.2K to 350K, supports a wide range of Cryogenic sensors like Silicon diodes (DT470 & DT670), Pt100, Carbon ceramic sensors, custom sensors, etc. A 12-bit A/D converter reads sensor inputs. An 8-channel PC-based data logger software with unlimited historical trends and real-time trends for the acquisition of temperature/resistance/voltage parameters is also developed. 5 such devices have been installed in beam hall phase-II which are placed 20 meters away from sensors. Hence these new TRV devices are now placed far off from the radiation area (Linac beam hall) and also from the control room (nearly 50 meters away from the device) for easy access during experiments. Besides their low cost, these devices are designed to replace the standard M/S Lakeshore 218 models at IUAC as an import substitution in the future. (author)