The disclosure relates to a method for silage temperature control in a silo. Measurement transmitters are placed at points where it is desirable to check the temperature of the silage located in the silo. These measurement transmitters are activated, on temperature control, by means of an activation transmitter with an antenna. On activation, the measurement transmitters transmit a signal which is related to the ambient temperature, this signal being received by a receiver. If a measurement transmitter indicates a temperature deviating from a predetermined norm, it is localized by direction finding.

The invention relates to analog multiplexing systems used in an industrial environment to derive small signals from remote locations. Since the signals received might mask a failure of the sensing devices a bias source is used to generate an anomalous signal when sensing is defective. The bias source is common to all points of measurement. It has a small time constant so that it can be switched at the multiplexing frequency, and it is operative only at the inception of the time interval for signal derivation so that measurement is not affected. Provision is made for purging successively the signal transmitting cables before signal derivation.

A method and apparatus features a system for automatically monitoring the operating environment and other physical conditions around and in which a host computer system operates. Sensors located around a computer system, including inside equipment cabinets and under the floor where cabling and air are ducted, are used to collect data that is frequently and periodically collected and stored along with an indication of the time and data of collection. The stored data is checked against a list of environmental parameters for the location of each sensor and an indication given when measurements indicate an environmental condition is outside discrete limits and rates of change of conditions. The stored parameters may be changed at any time from a console of the computer system. The stored data is also used to prepare histograms that are used to indicate trends in environmental conditions that can point to potential problems that may then be remedied before actual problems arise, and to faulty computer system installation design. Generation of histograms may be requested from remote locations via telephone links and then forwarded over the links to the remote locations for analysis. Trouble conditions indicated by out of parameter limits checking causes alarms to be given at the computer site and to be selectively sent to remote sites to initiate remedial action. In addition, a failsafe monitoring operation monitors the communications between the computer system and the monitoring apparatus to detect troubles.

The present invention includes an automatic commodity or services billing and metering system that when installed does not damage any existing meters or gauges, will fit virtually all known meters and gauges, and has incorporated into the system programmable reading ability to allow reading and accumulation of data by unit, hourly, daily, weekly, monthly or any other form of counting required by the customer. The meters are read by various means, one method is by counting and or sensing radiation increases and decreases of radiation emitting from a meter hand or gauge passing a sensor to generate a count. The read data is then sent via the Internet through the telephone line, by satellite, or by cellular phone connection to an offsite central billing and payment processing center where the rate payer and the utility or customer will have various forms of programmable access to its consumption data.