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The RM-80 Microprocessor

The RM-80 Microprocessor is designed for two types of applications: area configurations with stand-alone detectors and process configurations with detectors integrated into skid assemblies which contain detector support equipment such as pumps, valves, flow sensors, flow control valves, and samplers. Area configurations are used for conventional area monitoring, adjacent-to-line, and inline process monitoring. Process configurations are used to monitor a sample from a liquid, airborne process stream, or a local atmosphere.

The function of the RM-80 Microprocessor is to control the operation of a radiation monitor assembly which contains one or more radiation detectors and the detector support equipment. The RM-80 Microprocessor performs data acquisition from detectors, process sensors, and digital status inputs through various boards as shown in the RM-80 block diagram. An RM­80 Microprocessor can accept up to four inputs form pulse type detectors and up to two inputs from current type detectors. Data acquisition is followed by data reduction for detector and sensor inputs which includes validity checking, digital filtering to reduce statistical fluctuations, conversion, and compression. Compression consists of taking current values calculated every 0.6 and 6 sec and generating history files within twenty-four 10-min averages, twenty-four 1-hr averages, and twenty-eight 24-hr averages. Data analysis consists of comparing reduced data against alarm setpoints stored in the RM-80 Microprocessor data base. An alarm condition in any channel turns on a local alarm light and horn, changes the state of alarm relay contacts, and sets an alarm status bit for external communications.

Both types of RM-80 Microprocessors perform the following test functions:

Loss of Detector Counts Failure of the RM-80 Microprocessor to receive a count over a certain period of time will cause a failure alarm.
Checksource Test The RM-80 Microprocessor will initiate a checksource test upon operator request. This function can also be set to occur on a fixed interval. Insufficient count received from a checksource test will cause a failure alarm.

An RM-80 Microprocessor for process monitors can provide the following control functions:

Flow Control The sample flow rate is obtained from a flow sensor on the monitor. A flow rate outside the setpoint plus/minus a deadband will cause the RM-80 Microprocessor to adjust the monitor's flow control valve in the appropriate direction until the flow rate is within limits.
Pump Control The RM-80 Microprocessor shuts a pump off when the flow rate drops below a low-flow setpoint for a specific period of time. The RM-80 Microprocessor will also start or stop a pump upon operator request.
Purge Control The RM-80 Microprocessor will actuate purge valves upon operator request. The purge function can also be set to occur on a fixed interval.
Isokinetic Control Process flow rate input to the RM-80 Microprocessor can be tracked such that the ratio between sample and process flow rates (isokinetic ratio) is maintained at a setpoint plus/minus a deadband.

The RM-80 Microprocessor is designed to operate as a stand-alone device in conjunction with its detector and support equipment. For external communications, the RM-80 Microprocessor has three serial communications ports. Two redundant communication ports are used to communicated between the RM-80 Microprocessor and an integrated RMCS. The third port is used for safety-related and other critical monitors to communicate with a remote, dedicated RM-23A Control/Display module. RMCS and an RM-23A Control/Display Module continuously poll the RM-80 Microprocessor for radiation level and operation status.



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