Measurement Computing Personal Daq rev.6.0 - Manual (Page 28)

2-8 General Information & Specifications 878595 Personal Daq User’s Manual
Frequency Measurements (Not applicable to Personal Daq/54)
Each frequency/pulse input channel can measure from DC to 1 MHz, offering pulse count (totalize),
frequency, and duty cycle type readings. The input voltage range is -15 to +15 VDC absolute maximum.
TTL sense levels, Schmitt-trigger inputs <1.3 V (low), >3.8 V (high).
Note that each frequency channel can measure pulses that are due to closures of a contact between the
input terminal and the Lo terminal. This is because an internal pull-up resistor places the input at +5V
when the contact is open and allows the input to go to 0V when the contact is closed.
Frequency and pulse measurements can be scanned along with analog input measurements with resolution
up to 7 digits.
Digital I/O (Not applicable to Personal Daq/54)
You can program each digital I/O line individually as input or output. Digital input lines can be read as
part of the analog scan sequence and can be scanned over 100 times per second. Digital output lines can be
updated at any time prior to, or during an acquisition sequence; or can be automatically updated.
Digital input voltage ranges from 0 to +15 VDC are permitted, with thresholds of: <1.3V (low) and
>3.8V (high). In the output mode each output is an open-collector, with each bank of eight outputs
capable of sinking up to 150 mA for direct drive applications. External pull-up voltages can be up to +15
VDC (Over-voltage is rated at +20 VDC for up to 1 minute). Refer to the following figure for information
regarding Digital I/O connection.
Personal Daq, Digital Output Connections
Note: The figure represents connections for one channel (D8). The other seven
channels (D1 … D7) are connected in the same manner.
Note: The maximum load current is 150 mA per 8-channel bank, or
if all eight channels are used, 18 mA (max) per channel.