Products - Satellite Test and Analysis System

      This control system is basically used for artificially generating space conditions in a closed chamber in which satellites are tested for their performance prior to their launch into outer space. 

 click here for the Configuration Diagram

The system has mainly four subsystems, each catering to different functions:

    The Data Processing Unit (DPU) is the central part of the system where all the data collected by the various sub-systems are concentrated. The DPU continuously logs the ascquired data into a MS SQL Server 6.5 database for offline processing. Besides this the DPU forms the main user interface for the entire system from which the user configures the system, controls the various sub-systems, monitors the health of the sub-systems, performs both online as well as offline data analysis etc. The DPU consists of two Compaq Servers, one used as the Main Server and the other used as the Backup Server to take over the system operation in case of failure of the Main Server. There is a RAID where the system stores all the data common between the Servers. Windows NT Cluster Kit manages the redundancy of the Servers. Besides there are four Digital Workstations which are used only for data monitoring and performing data analysis. These Workstations connect to the Servers using NetDDE to get data.

    The “Thermocouple Signal Processing Unit” (TSPU) acquires temperature data from 512 T-type thermocouples, performs Engineering unit conversions on the data and sends these data to the Servers using Modbus on Ethernet. The TSPU is based on Motorola 68040 CPU VMEbus Systems running control software developed in Ultra C/C++ on RTOS OS9.

    The “Power Supply Signal Processing Unit” (PSPU) controls and acquires data from 128 programmable power supplies. The power supplies are multi dropped on a RS485 bus in groups of 16 power supplies each in a Master Slave configuration. The PSPU acts as a Master while each of the power supplies act as Slaves and are assigned unique slave addresses. A Microcontroller Card is used to acquire the parameters like Voltage, Current and fault signals like over voltage, over current, over temperature, output relay status etc. and transmit it back to the PSPU. The setting of the voltage of each power supplies and also the output relay (ON/OFF) is remotely controlled by the PSPU with the RS485 interface running at 19.2 Kbps. These power supplies inturn heat various heating elements like IR lamps and skin bound heaters to control the temperature inside of different parts of the satellite. A maximum of 128 self-tuning closed loops can be run in the PSPU to automatically maintain the set temperatures. The PSPU also uses the Modbus protocol to communicate with the Servers. The PSPU is based on two Motorola 68060 CPUs VMEbus Systems running control software developed in Ultra C/C++ on RTOS OS9. The two CPUs are used in a multiprocessor configuration so that one CPU acts as a standby in case of failure of the other.

    The “Gateway” is based on a lower end Motorola MC68360 CPU based system and acts as a “gateway” between the Satellite and the Data Acquisition and Control system. The main function of the Gateway is to buffer the data sent by the satellite, do some engineering unit conversions on these data and pass it on to the Servers. The Gateway control software also runs OS9 and uses the Modbus protocol for communicating with the Servers.