Safety Engineering / Building Automation

Conceptual formulation: In a new office building all failure and operational notifications are to be centrally registered and protocolled by security personnel. The failure notification system was already operational and most of the building sections were integrated into the profibus-network. Only the sprinkler system, heating, and pumping station had to be connected. The control system for these units did not have the appropriate interfaces.

Implementation: The controlling system for the sprinkler system already accumulated failure notifications in the fire warning center, but did not have an external interface. We entered the required 8 notifications digitally into a Simatic-S7-300-PLC and made it accessible via profibus-coupler to the failure notification system. A Klöckner Moeller PS4-PLC was built into both heating control systems, however, which due to a lack of space in the switching cabinets, could not be expanded. We added an additional PS4 externally and connected the 3 PLCs via master coupling. The gathered data were transferred to the central building control system via profibus interface module. Because the pump station was located near the heating unit we integrated the failure warning output into the heatíng unit-PLC.

Safety Engineering / Heating Unit for Sprinkler Systems

Conceptual formulation: In case of fire sprinkler systems spray water on the burning area. When sprinkler pipes run through an area exposed to frost they have to be heated in order ensure the flow of water in emergency situations. According to VdS, the heating and the temperature sensors have to be redundantly layed out. Further safety regulations are the monitoring of current temperature, sensors for short circuits and breaks in the cable, fuses, and circuit breaker triggering etc.

Implementation: We have developed solutions in PLC for more than 50 facilities. Over the years there have been a wide variety of control systems employed. They are the following: Klöckner Moeller PS 3, Moeller PS4, Mitsubishi FX0S, Siemens S7-200 and Siemens S5-95U. The temperatures were acquired analogically and the various switch points (cable fracture, sensor short circuit, extreme temperature fluctuation, heating on/off) were adjusted by software. In order to keep power consumption at a minimum the temperatures are checked as directly as possible at the coldest point on the pipe (not as in usual outdoor temperature measurement). All failure warnings are signaled by LED. A potentially free contact for the control center or building automation garantees that no malfunction goes undetected.

Safety Engineering / Fault Alarm Evaluator

Conceptual formulation: An oil tank plant is given the safety engineering task of installing a fault alarm evaluator system centrally. All of the available existing decentralized Fault Alarm installations have to be centralized. These include: overflow and leakage alarms, pumping failure, grounding failure, pumping unit, oil separator system, and extinguisher installations. It is also to be ensured, per slide valve monitoring, that only a certain number of tanks are to be opened. Lastly, costs have to be kept at a minimum.

Implementation: A bus system was used to reduce costs in cabeling due to the relatively long distances, ca. 520m, between separate installations.The PS4-200-MM1 was used when the Moeller GmbH PLC implemented. There was a price advantage over the other manufacturers because they and all additional decentral modules were integrated into bus-interface (the K-Bus). The single point information was displayed centrally in LEDs. New data and sporadic warnings were registered and documented According to DIN. For all past and present failure notifications a mandatory acknowledgement requirement has been added.