TDT RZ2, Manual

Page: 138 / 736

3-6 System 3
RX8 Multi I/O Processor
Status Indicators
Cyc: cycle usage
Ovr: processor cycle overages
Bus%: percentage of internal device's bus capacity used
I/O%: percentage of data transfer capacity used
Important! The status lights will flash (~3 times a second) to alert the user when a device
goes over the cycle usage limit, even if only for a particular cycle. This helps to
identify periodic overages caused by components in time slices.
Bits Lights
The RX8’s eight Bits lights are user configurable. By default the Bits lights indicate
the logic level (lit when high) for the eight bit-addressable digital I/O lines. The
Bits lights can also act as logic level lights for any of the other bytes of digital I/O.
Analog Input/Output
The RX8 can have a maximum of 24 channels of analog I/O accessed via the 25-
pin connector on the front panel. Each bank of up to eight channels of I/O is user
configurable with either PCM or sigma-delta converters.
Sigma-delta converters provide superior conversion quality and extended useful
bandwidths, at the cost of an inherent fixed group delay. When equipped with
sigma-delta, the RX8 DAC Delay is 23 samples and the RX8 A Delay is 47
samples.
This device can sample at rates up to ~100 kHz. For additional information on
sampling rates for both PCM and sigma-delta converters, see “Realizable Sampling
Rates for the RX8” on page 3-9.
Note: Because of device timing constraints at higher sampling rates, only the first 23
channels of analog I/O are processed when operating the RX8 at ~100 kHz.
The analog I/O of each device is custom configured at the factory. Problems will
arise if end users do not carefully note the configuration of their RX8 device. This
topic provides information about configurations and channel numbering. The RX8's
analog I/O channels are accessed via a 25-pin connector on the front panel. If you
know what channel numbers your device uses, See “RX8 Technical Specifications”
on page 3-10 or the Analog I/O pinout diagram.
Organization of Analog I/O Blocks
The RX8 has three blocks of I/O ports. Each block can house up to eight channels
for a total of 24 channels of analog I/O. Blocks can only be filled by analog I/O
modules of the same type.
For example:
A block can be configured with all D/A’s or all A/D’s, but not a mixture of D/A’s
and A/D’s. In addition, the D/A’s and A/D’s must be of the same type (either
PCM or sigma-delta).