Measurement Computing PMD-1024HLS, User Manual

Chapter 1 

Introducing the PMD-1024HLS 

This user's guide contains all of the information you need to connect the PMD-1024HLS to your 
computer and to the signals you want to measure. The PMD-1024HLS is part of the Personal 
Measurement Device brand of USB-based data acquisition products. 

The PMD-1024HLS is a USB 2.0 low-speed module supported under Microsoft® Windows® 98 (2

nd

edition), Windows ME, Windows 2000, and Window XP. It is designed for USB 1.1 ports, and was tested 
for full compatibility with both USB 1.1 and USB 2.0 ports.  

Refer to the "Be sure you are using the latest system software" note in Chapter  , "

," to make sure you are using the latest USB drivers.  

2 Installing the PMD-

1024HLS

The PMD-1024HLS is a high drive, 24-line digital I/O module that includes one 32-bit external event 
counter. The PMD-1024HLS is powered by the +5 volt USB supply from your computer. No external 
power is required. 

An emulation of the 82C55 in mode 0 (only) sets the direction of the 24 digital I/O lines in four ports. 
Each digital port can be configured for either input or output. The 74FCT244 outputs are high-drive TTL, 
capable of sourcing 15 mA and sinking 64 mA. 

The PMD-1024HLS is shown in Figure 1-1. All I/O connections are made to the screw terminals on each 
side of the PMD-1024HLS. 

Figure 1-1. PMD-1024HLS 

1-1