D0 General Support: The Use of Programmable Logic Controllers (PLCS) at D0

[摘要] With the exception of control of heating, ventilation, and air conditioning (HVAC) ventilation fans, and their shutdown in the case of smoke in the ducts, all implementations of Programmable Logic Controllers (PLCs) in Dzero have been made within the fundamental premise that no uncertified PLC apparatus shall be entrusted with the safety of equipment or personnel. Thus although PLCs are used to control and monitor all manner of intricate equipment, simple hardware interlocks and relief devices provide basic protection against component failure, control failure, or inappropriate control operation. Nevertheless, this report includes two observations as follows: (1) It may be prudent to reconfigure the link between the Pyrotronics system and the HVAC system such that the Pyrotronics system provides interlocks to the ventilation fans instead of control inputs to the uncertified HVAC PLCs. Although the Pyrotronics system is certified and maintained to life safety standards, the HVAC system is not. A hardware or software failure of the HVAC system probably should not be allowed to result in the situation where the ventilation fans in a smoke filled duct continue to operate. Dan Markley is investigating this matter. (2) It may also be prudent to examine the network security of those systems connected to the Fermilab WAN (HVAC, Cryo, and Solenoid Controls). Even though the impact of a successful hack might only be to operations, it might nevertheless be disruptive and could be expensive. The risks should perhaps be analyzed. One of the most attractive features of these systems, from a user's viewpoint, is their unlimited networking. The unlimited networking that makes the systems so convenient to legitimate access also makes them vulnerable to illegitimate access.

[发布日期] 2000-05-05 [发布机构] Fermi National Accelerator Laboratory

[关键词] Blowers;Safety Standards;Heating;Monitors;Hvac Systems