Controlling Devices with Relays

摘要

Irecently was given the curious task of making noise on a factory floor at set intervals. The company wanted to use this noise to provide important auditory cues for specific events. These events included the time employees should clock in, clock out, take a break and return from break. The solution I implemented has been working well, and everyone involved has been pleased with the results. The gratitude I receive from employees that clock in and clock out is related directly to the inaccuracy of their own personal timepiece―those with fast watches appreciate the apparent extra time they have before clocking in. Later, though, they curse me for being delayed in clocking out when the watches on their wrists clearly show it is time to go. The company I work for uses barcode clock terminals placed throughout the plant to record the time that employees clock in and clock out. In addition, the barcode clocks also record what job each individual employee is performing. When an employee clocks in or out, the employee scans his or her identification badge and a barcode representing the job the person is doing. The clock terminal copies this data to a buffer, along with a timestamp of when the items were scanned. CMINet, a data collection system running on two Microsoft Windows NT systems, is used to acquire the data from the clocks. The clocks are polled every minute or so to retrieve the data held in the clock terminal's buffer. During polling, the clocks also are set to the local time of the machine polling the clocks. The data acquired from the clocks is later imported into the enterprise resource planning (ERP) system for job costing and payroll.