{"id":3880,"date":"2020-09-25T19:56:57","date_gmt":"2020-09-26T02:56:57","guid":{"rendered":"http:\/\/www.k6bj.org\/?p=3880"},"modified":"2021-05-25T18:06:17","modified_gmt":"2021-05-26T01:06:17","slug":"k6bj-2-meter-repeater-aux-input-panel-2","status":"publish","type":"post","link":"https:\/\/k6bj.org\/wordpress\/archives\/3880","title":{"rendered":"K6BJ 2-Meter Repeater Aux Input Panel"},"content":{"rendered":"

K6BJ 2-Meter Repeater Aux Input Panel\u00a0Temperature and Power Monitoring<\/h4>\r\n

Introduction<\/b><\/p>\r\n

The recent upgrade to the K6BJ 2-meter repeater includes a new Arcom RC210 repeater controller. The controller has a number of capabilities not currently in use. This document covers the addition of an auxiliary input panel to allow easy connection to the controller\u2019s multiple digital outputs and analog and digital inputs, and the connection of sensors and circuitry to allow monitoring of temperatures and power voltages. Also covered are the controller programming additions needed to make use of the new sensors, and possible future capability enhancements.<\/p>\r\n

Arcom RC210 Connection<\/b><\/p>\r\n

The Arcom RC210 Repeater Controller includes on its rear panel one DB-25 connector intended for the connection of peripheral equipment. This connector provides 8 analog inputs, 5 digital or alarm inputs, and 7 digital outputs. (See Arcom Version 3.5 Hardware Manual<\/i>). To make these connections available for convenient use, we now add a shielded DB-25 cable to bring signals to screw terminals on a 3\u00bd inch panel to be installed at the rear of the repeater rack.\u00a0 <\/span>See Fig. 1.<\/p>\r\n

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Temperature and Power Voltage Sensing<\/strong><\/p>\r\n\r\n\r\n\r\n

Circuitry for the connection of temperature sensors and for monitoring power voltages is contained in a small metal enclosure affixed to the auxiliary input panel adjacent to the screw terminal blocks.\u00a0<\/p>\r\n\r\n\r\n\r\n

AC Voltage Sensing<\/strong><\/p>\r\n\r\n\r\n\r\n

AC power from the power grid or the repeater shack\u2019s AC generator is monitored at the AC power receptacle at the base of the repeater equipment rack. A small transformer mounted to the rack panel steps down the voltage and provides ground isolation. Voltage from the transformer\u2019s secondary is rectified, filtered, and scaled to produce a signal between 0 and +5VDC which is proportional to the AC power voltage. This connects to the controller\u2019s AD3 Analog Channel 3 input. Scaling constants in the controller software allow it to report the power as AC volts.<\/p>\r\n\r\n\r\n\r\n

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Battery Voltage Sensing<\/strong><\/p>\r\n\r\n\r\n\r\n

Battery voltage is sensed at the fuse block in the repeater rack. Resistors scale the voltage to the 0-to-5-VDC input range of the controller\u2019s A-to-D converter at AD4. Scaling constants in the controller software allow it to report actual battery voltage.<\/p>\r\n\r\n\r\n\r\n

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Temperature Sensing<\/strong><\/p>\r\n\r\n\r\n\r\n

Temperature is measured using an LM35, an inexpensive IC with an output voltage directly proportional to temperature, varying 10mV\/\u00b0C. One sensor is in the equipment rack near the Yaesu DR-1X radio, and one sensor is outside affixed to the north wall of the repeater shack. Sensors are powered from the controller\u2019s stabilized A-to-D reference voltage. Sensor current is limited to about 80 \u00b5A to prevent errors due to self-heating. Sensor connection is via twisted-pair CAT-5 cable. Small bypass capacitors shunt any RF voltage induced on the cable runs.\u00a0<\/p>\r\n\r\n\r\n\r\n

Inexpensive LM35 sensors have an accuracy of \u00b11\u00b0C. Their output is scaled to read degrees Fahrenheit with calibration constants programmed into the RC210.\u00a0<\/p>\r\n\r\n\r\n\r\n

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Controller Programming<\/strong><\/p>\r\n\r\n\r\n\r\n

Status Query\u00a0<\/strong><\/p>\r\n\r\n\r\n\r\n

The following query commands are supported:<\/p>\r\n\r\n\r\n\r\n

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  1. AC Power Voltage
    DTMF command code: [TBD]
    Repeater response: \u201cAC power xxx volts AC\u201d<\/li>\r\n
  2. Battery Voltage
    DTMF command code: [TBD]
    Repeater response: \u201cBattery xx.x volts DC\u201d<\/li>\r\n
  3. Outside Temperature
    DTMF command code: [TBD]
    Repeater response: \u201cOutside temperature xx degrees\u201d [requires custom DVR track]<\/em><\/li>\r\n
  4. Rack Temperature
    DTMF command code: [TBD]
    Repeater response: \u201cInside temperature xx degrees\u201d [requires custom DVR track]<\/em><\/li>\r\n<\/ol>\r\n\r\n\r\n\r\n

    Alarm Conditions<\/strong><\/p>\r\n\r\n\r\n\r\n

    AC Power Loss:<\/p>\r\n\r\n\r\n\r\n

    If the AC power drops below 102 VAC as measured by the RC210 Repeater Controller, the following actions occur:<\/p>\r\n\r\n\r\n\r\n