32 Channel Digital I/O Expansion Module

The PCI-20004M-1 option module adds 32 points of TTL-compatible digital I/O to any expandable Intelligent Instrumentation board. The 32 points are arranged in 4 ports of 8 bits each. Using software, you can select each port as either input or output. All lines are buffered to give full, bipolar, TTL drive capability.

The PCI-20004M-1 monitors or controls devices with discrete on/off states, such as relays, switches, lamps, etc. Through the use of opto-isolators (PCI-1100 Series), you can also interface to non-TTL signals. For example, you can switch loads such as AC or DC motors and detect the presence of AC line voltage.

In addition to reading (or writing) bytes, software can extract individual bits or assemble words. In this way, you can use the option module to test logical combinations and determine alarm or control conditions.

• 32 Digital Input/Output Points

• TTL-Compatible Levels

• Buffered Outputs, Both Source and Sink Current

• Compatible With Industry Standard Opto-Isolators

• Low Input Capacitance

Parameter	Conditions	Specifications
Digital I/O*
Number of Ports		8 channels (bits) each 4
Input Levels		TTL compatible
Output Levels		TTL compatible
Source Current	Vout = high	15mA
Sink Current	Vout = low	24mA
System Throughput**
Digital I/O		400Kbytes/second
Physical Characteristics
Power Requirements***		+5V 350mA maximum
Operating Temperature Range		0 to 70° C
* All digital I/O points are programmable as either inputs or outputs in byte-size groups (8 channels each).
** Hardware limit only. Software may reduce speed.
*** Refer to the data sheet of the host board to determine available power.