Posted By Rob Waldie We are currently at the start of a project to replace our control room. The current control room comprises of MIMIC panels, it is proposed that the MIMIC will be completely replaced by VDU's. I am concerned that VDU's will not provide operators with an adequate overview of the process and the approach should be a combination of MIMICs and VDU's Does anyone have views or experience of this causing safety problems ( especially in an emergency )

Posted By David Allan As an ex nuclear submarine manouvering room watchkeeper the need for effective graded alarms and accurately reproduced readings is obviously vital. The confusion following alarms and misread readings etc was a major contributing factor in the Three Mile Island incident and in the Kegworth Air Crash. Our training always focussed on key readings first, then if safe, deal with the rest. I would obviously feel more comfortable with a combined (ie some direct reading meters for vital measurements/controls)approach for redundancy and verification purposes, but software developments have taken the VDU approach to new and sophisticated levels. The need for continuing power supplies to allow VDU function would worry me and what about fire/emergency evacuation of the control room? The only way to be sure is to conduct a full appraisal using, HAZOP, ETA, FMEA etc, not forgetting the ergonomic requirements of the panels and the operators. Hope this helps, David

Posted By Roy Macpherson Rob The control room at our power station has a mix of VDU based displays and mimic panels for indications for all of our plant. In most cases the VDU system updates the system condition much faster than the mimic displays and is more accurate in its display of process systems. It also allows for much more data to be available to the operators which in normal circumstances is great. The major problem however is the loss of power supplies, this has in the past led to some extremely interesting situations-we lost all power at 3am and the backup power supplies which were supposed to last for 8 hrs in fact crashed after 20 mins. Fortunately all the systems are failsafe and the units rolled to a stop safely but without the indication on the VDU's we had to rely on what information came back to us through the old analogue instrumentation. Not an ideal situation and one that caused a massive upgrade of backup power supplies. Another thing to be careful of is touch sensitive screens, they are very useful but I have seen a whole batch of product trashed by thoughtless finger poking on a touch screen by an electrician tracing a system and tapping on the screen to make his point to the operator!