Programmable hour meter for recording elapsed operation time

• US 4,941,136 A
• Filed: 09/13/1988
• Issued: 07/10/1990
• Est. Priority Date: 09/13/1988
• Status: Expired due to Fees

• Current Assignee: Stewart Warner Corporation 1826 Diversey Parkway Chicago IL
• Original Assignee: Stewart-Warner Corporation (Schneider Electric SE)
• Inventors: Breitung, Edward J. II
• Primary Examiner(s): Roskoski, Bernard
• Application Number:
  US07/243,919
• Time in Patent Office: 665 Days
• Field of Search: 368/5, 368/8, 371/66
• US Class Current: 368/8
• CPC Class Codes: G04F 10/04 by counting pulses or half-cycles of an ac G04F10/005 takes precedence
• CPC Class Codes: G07C 3/04 using counting means or digital clocks
• CPC Class Codes: G07C 5/04 using counting means or digital clocks

Abstract

A completely electronic programmable hour meter is disclosed. The hour meter accumulates and displays run time of the device being measured. The hour meter can also count pulses. The meter can be preprogrammed with a maintenance timer limit which is compared to the accumulated run time. If the accumulated run time equals or exceeds the preprogrammed time limit an alarm display flashes. The hour meter will store the accumulated run time for up to 5 years if power is interrupted. This memory retention occurs without use of a battery. The elapsed time is stored in a plurality of registers such that no register is written to more than a preselected number of times, nominally ten thousand, until all the registers have been updated the preselected number of times.

Claims

1. A programmable elapsed time meter comprising:

an electronic circuit including means for calculating elapsed time, E² PROM memory means having a plurality of registers for storing the calculated elapsed time, and means for continually updating the the stored calculated elapsed time in said plurality of registers such that no register is updated more than a preselected number of times until all the registers have been updated said preselected number of times;

input terminals for enabling said electronic circuit;

a liquid crystal display connected to said electronic circuit, capable of displaying the elapsed time stored in said electronic circuit; and

a capacitor connected to said electronic circuit for supplying power to said electronic circuit to enable the electronic circuit to update the E² PROM memory means at power shutdown.

2. The programmable elapsed time according to claim 1 wherein said electronic circuit is configured to measure and record pulses.

3. The programmable elapsed time meter according to claim 1 wherein said liquid crystal display displays five digits and a maintenance pixel.

4. The programmable elapsed time meter according to claim 3 wherein said electronic circuit can store a maintenance time limit and said electronic circuit compares the maintenance time limit with the elapsed time and flashes a warning pixel on said liquid crystal display if the recorded time is greater than or equal to the maintenance time limit.

5. The programmable elapsed time meter according to claim 4 wherein said electronic circuit can be configured to display 1 digit to the right of the decimal point.

6. The programmable elapsed time meter according to claim 3 further comprising a view switch input connected to said electronic circuit wherein said liquid crystal display will display the accumulated time for up to 5 seconds after said view switch input is engaged and the accumulated maintenance time will be reset to zero when said view switch input is engaged for 5 seconds upon powering up said circuit.

7. The programmable elapsed time meter according to claim 1 further comprising a housing wherein said liquid crystal display is visible through a face in said housing.

8. The programmable elapsed time meter according to claim 1 further comprising external connections from said electronic circuit to an alarm wherein said electronic circuit can store a maintenance time limit and said electronic circuit compares the maintenance time limit with elapsed time and if the elapsed time is greater than or equal to the maintenance time limit said electronic circuit activates the alarm through said external connection.

9. The programmable elapsed time meter according to claim 8 wherein said alarm is an audible buzzer.

10. The programmable elapsed time meter according to claim 8 wherein said alarm is a warning light.

11. The programmable elapsed time meter according to claim 1, wherein said means for writing the elapsed time into said plurality of registers is a programmable microcontroller.

12. The programmable elapsed time meter as set forth in claim 1, wherein said preselected number of times is ten-thousand times.