Omega OMB-DAQSCAN-2000 Series Manuale Utente

DaqScan/2000 Series 

898195

 

Taking Measurements      8-5 

 

DaqScan/2001 and DaqScan/2004 allow the data source for synchronized DAC output 

operations to be that of an internal memory-based buffer.  The output data, for all channels, is 

contained in the buffer.  

Each DaqScan/2000 Series device allows asynchronous input of any counter or digital channel 

that is not currently configured for synchronous acquisition.  The circuitry allows for 

asynchronous output to any D/A channels that are not currently configured for waveform 

output.  Likewise, the digital port can be used for both asynchronous input and output 

operations.  In addition, the timer outputs can be programmed at any time regardless of the 

current state of synchronous or asynchronous operations on other channels.   

Local 8255 Channels  (P2: Port A, Port B, Port C) 

The devices have an implemented Intel 8255 core in the digital I/O logic on the P2 port.  With 

the Intel 8255 there are three 8-bit wide ports available for I/O and one 8-bit wide port for 

configuration purposes.  The configuration port is used to configure the other three 8-bit ports 

for either input or output operations.    

Local 16-bit P3 Port 

The 16-bit P3 digital port can be used as either an input or output port.  With this port, no 

configuration is required.  The port simply outputs when written to and inputs when read.   

The devices have the ability to expand their digital I/O capabilities via the P2 port and the 

connection of applicable digital I/O expansion modules.  These modules are discussed in the 

Option Cards & Modules User’s Manual (p/n 457-0905).  When using the digital I/O 

expansion modules the local P2 Intel 8255 digital I/O becomes inaccessible in lieu of the 

expansion modules.  These expansion modules provide additional Intel 8255 ports as well as 

input isolation for applications that require the expanded capabilities. 

Each device allows for the generation of output pulses based upon a programmable setting.  

These output timers can be set at any time regardless of the state of any synchronous or 

asynchronous operations which are currently taking place on other channels.  

The timer outputs are through screw terminals on the front panel. 

DaqScan/2001 and DaqScan/2004 can output analog data to any of their four D/A channels.  

Each D/A channel may be asynchronously updated by an application if the D/A channel is not 

currently being used for waveform output operations.  The four analog outputs are via P3 (see 

pinout in chapter 4).   

Counter Input Channels  (CTR0, CTR1, CTR2, CTR3) 
DaqScan/2000 Series devices have counter input capabilities and have the ability to read 

counter input providing that the counter channel is not configured for synchronous acquisition. 

As in the case of synchronous operations the four 16-bit counter input channels can be used 

individually or cascaded into two 32-bit counter channels.  For either cascaded or non-

cascaded counter channels each channel can be configured for:  

• 

Clear on Read Mode - specifies that each counter should be cleared (reset to 0) 

upon being read. 

• 

Continuous Totalize Mode – specifies that each counter is to free-run and not be 

cleared during the read operation.