Home of the ICON - Instrumentation and Control Over Networks Last updated April 1, 2007

     ICONIO Board
     1-Wire I/O Devices

     ICONIO Card Installation
     ICONIO Programming

     Basic 1-Wire Installation

     2 Chan Counter (OWCTR2)

     2 Chan A-D (OWAD2)

     4 Chan A-D (OWAD4)

     1 Chan Pot Out (OWPOT1)

     Dry Contact (OWRELAY4)

     Connections (OWCONNECT)

     Temperature (OWT)

     Relative Humidty (OWTRH)

     Light (OWL)

     Weather Station (OWWEATHER) 


     Phone: (406) 599-1053

2 Channel Counter (OWCTR2)


This 1-wire card uses the DS2423 IC to measure two counter/frequency channels. Each channel has a 10K pullup resistor to +5V. It is expected that you connect a dry contact between Common and the desired input channel or you use an input voltage that varies between 0 and 5V. Examples include a tipping bucket rain gauge, contact closure anemometer and light sensor. If you have a "noisy" switch you may wish to connect a capacitor between the input and common.

If the optional battery backup is ordered, the device will count even during a power failure (included with the tipping bucket rain gauge).

Card Type: 2
Card Type Description
2 2, 16 bit Modbus registers (2, 16 bit counter channels)

Connector CN2 (5-pin style) Pinout:
Pin Numbers Description
1 Common or Ground
2 Counter channel 1
3 Counter channel 2
4 Unused
5 +5V Power Output

Connector CN2 (6-pin style) Pinout:
Pin Numbers Description
1 Common
2 Unused
3 Unused
4 Counter channel 2
5 Counter channel 1
6 +5V Power Output

The "Type" must be 2 as described above. The "Mode" must always be "Separate power".

Modbus Register Information:
The device has two consecutive Modbus input registers on the ICONIO board, one for each counter channel. Each Modbus register value will count from 0 to 65534 and then, after 2 counts, wrap back to 0 again. The special value, 65535, indicates that the card has failed.

Parameter Specification
Temperature -40 to +85 C (-40 to +185F)
Input Impedance 10K ohm
Power 2 mA with both contacts closed.
Debounce Time 170-460 uS
Minimum Pulse Width 1 uS

Schematic and Parts List:
Reference Part Number
CN1 Digikey 281-1451-ND
CN2 Digikey 281-1452-ND
D1 Dallas Semi DS9503P
D2, D4, D5 Digikey SA5V0ADICT-ND
U1 Dallas Semi DS2423P
R1, R2 Digikey 10KQBK-ND

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