4-Digit Counter Schematic - DIY Kit 154. FOUR DIGIT...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
DIY Kit 154. FOUR DIGIT PRESETTABLE DOWN COUNTER PAGE 1 INTRODUCTION This is a low cost 4 Digit Presettable Down Counter with output and reset. The count input can be used for both high and low speed counting applications. The counter has four modes of operation that control how the output behaves when the count reaches zero. The input, output and power supply pins are brought out to a 10-way header strip for easy connection. A 9 to 12V DC supply is required to power the kit, which has a current consumption of 20mA to 40mA, depending on the number displayed. A 12VDC / 150mA plug pack will do fine. TECHNICAL SPECIFICATIONS Supply voltage 50mA @ 12VDC Operating modes Count Stop, Output Hold Over-Count, Output Hold Auto-Reset, One-Shot Output Over-Count, One-Shot Output Count range 0000 to 9999 (10,000 max) Count speed Low (selectable) High 30 cps (15mS high, 15mS low) 30,000 cps (measured) Inputs Reset, Count, Rate Output Transistor, NPN, 100mA @ 30V Display 14mm RED LED Physical size 51mm x 63mm (2.0” x 2.5”) Connection 10 pin SIL header pins, 0.1” INPUTS AND OUTPUTS These are organized as ‘pairs’ of pins, with each input or output having a corresponding ground pin. Inputs are normally pulled high and may be driven low by simple “make” contacts from switches, relays or open collector outputs. There are three inputs: RESET Resets the counter to its preset value RATE Selects if debouncing is applied to the count input COUNT Triggers counter on falling edge The RATE input is used to enable or disable debouncing on the count input. With RATE high (open) debounce is enabled; with RATE low (closed) debounce is disabled. Enable debounce when using relay contacts or switches for input. The debounce time is 15mS for both falling and rising edges. This means the count input must be stable for at least 15mS before it is recognized, giving a maximum counting speed of about 30 counts per second. The open collector OUTPUT pin indicates when the count has reached zero. It needs an external pull-up resistor or it can be used to directly switch a relay. The OUTPUT is normally ‘high’ and either pulses ‘low’ or remains ‘low’ depending on the operating mode. Open Collector Output. For more information read the note at www.kitsrus.com/zip/opencol.txt OUTPUT PULSE WIDTH (Mode C and D only) The OUTPUT goes low when the count reaches 0000. It stays low until the next valid count input when it goes
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/07/2011 for the course ECE 209 taught by Professor Arif during the Summer '11 term at National Institute of Technology, Calicut.

Page1 / 3

4-Digit Counter Schematic - DIY Kit 154. FOUR DIGIT...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online