PMD-1024HLS User's Guide

Functional Details

If you want to sink the maximum of 64 mA per DIO line, you can only do so with up to six lines (440 mA

÷64 mA/line = 6.8 ≈ 6 lines). To sink current with all 24 DIO outputs at any one time, you can sink a maximum of 18 mA per line.

Ground terminals

The nine ground (GND) connections are identical, and provide a common ground for all PMD-1024HLS functions. Refer to the pinout diagram on page 3-2for the location of the GND terminal.

Counter terminal

Pin 20 (CTR) is the input to the 32-bit external event counter. Refer to the pinout diagram on page 3-2for the location of this terminal. The internal counter increments when the TTL levels transition from low to high. The counter can count frequencies of up to 1 MHz.

Pull-up/pull-down terminals

You can wire pin 11 (Port C Pull-up/Pull-down), pin 13 (Port B Pull-up/Pull-down), and pin 15 (Port A Pull-up/Pull-down) to support a pull-up or pull-down connection. These terminals configure the internal 47K resistors on the PMD-1024HLS.

Refer to the pinout diagram on page 3-2for the location of these terminals. These terminals are configured as open by default.

ƒTo configure a pull-up connection for a specific port, wire the pull-up/pull-down terminal to a USB +5 V terminal.

Figure 3-5. Pull-up connection for Port A

3-5

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Measurement Specialties PMD-1024HLS manual Ground terminals, Counter terminal, Pull-up/pull-down terminals