Doc: ps2001-5-1101-001 Rev: R02. 00
Devices (valves and drives)
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1486357009-URS, URS
| Devices (valves and drives) (27) Device handling modules will be provided for the following types of common devices • Normally open isolation valve • Normally closed isolation valve • Positive acting modulating valves (opens with increasing signal) • Negative acting modulating valves (closes with increasing signal) • Bistable valves • Direct online drive (on/off drive) • Variable speed drive (28) Device handling modules shall be configurable to include state feedback (e.g. opened/closed limit switches fora valve, positive running detection fora drive, position or speed feedback c, partial state feedback (e.g. an only opened or an only closed limit switch fora valve) or no state feedback (no limit switches on a valve, no running state detection on a drive or no position or speed feedback c. (29) Device handling modules will detect fault conditions with the associated device if the device capable of reporting faults (either directly or by inference, this will include but not be limited to failed to start/open, fail to stop/close, failed to achieve speed/posi- tion, overload conditions for drives and motorised items. (30) Device handling modules will be capable of responding to the different interlock types listed in § 4.2.2-(12). (31) Device handling modules will have the facility to respond to safety signals (such as emergency stop signals. 48-71 Doc PS Rev Rb Messages alarms, warnings, events and prompts (32) Alarm and warning generation (both low and high) will be provided for all scaled instrument values, these shall have the facility to be time filtered and will have hysteresis filtering to prevent nuisance “chattering” alarms. Alarms and warnings may be self-resetting or latching. (33) Individual analogue alarm and warning modules will be provided for any analogue value, each alarm or warning shall have the facility to be active high or low, and shall have the facility to be time filtered and will have hysteresis filtering to prevent nuisance “chattering” alarms. Alarms and warnings may be self-resetting or latching. (34) Digital alarm and warning modules will be provided for any digital signal, each alarm or warning shall have the facility to be active high or low and shall have the facility for being time filtered on both rising and falling edges. Alarms and warnings may be self- resetting or latching. (35) Alarms and warnings will not be timestamped at the controller level it is assumed that this will be done by the supervisory system. (36) Modules will be provided to allow event and prompt information to be passed to supervisory systems. Events will be simple records of actions that have occurred (for example, a target temperature has been reached, these messages will be logged by the supervisory system. Prompts will be signals to the supervisory system that a particular action is required by the operator (e.g. ready to start cleaning cycle. Prompt modules will have the facility to queue messages in the order they occur. (37) A module will be provided to timestamp the occurrence of a signal (this may be an alarm or warning, the time stamping will use the Controller real time clock and will have an accuracy of at least 1 millisecond. Low alarms or warnings occur when an instrument value is at or falls below a target value, high alarms and warnings occur when the value is at or above a target value. Doc PS Rev R 49-71 (38) The timestamp module will record the following • Time the event began • Time the event ended • Duration of the event • Time of any operator acknowledgement Download 1.5 Mb. Share with your friends:
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