Technical data

ASTi DACS: Operation & Maintenance Manual (Version 4, Rev. B.1) www.asti-usa.com

Network Interface

Connector Type: RJ45 (100BaseT)

Speciﬁcation: The DACS, as a standard product, supports the Ethernet IEEE 802.3 standard.

The card is 10/100 Mbs autosensing, and can be used for either 10 or 100 Mbs networks.

Interface: The DACS supports UDP level protocol. IP format addressing is used under UDP.

For receipt of state information from simulation applications the Model Builder runtime environ-

ment supports a wide variety of data formats including ﬂoating point, boolean, ascii, and ﬁxed

point signed and unsigned integers of varying lengths, etc. Support is provided for big endian and

little endian formats and IEEE and Gould/Encore format ﬂoating point numbers. Boolean ﬂags

can be either bit or byte variables.

The layout of the packet can be that which is most advantageous for the host computer, since each

input object has its variable deﬁned as a byte (and bit if applicable) offset from the start of the

packet. This avoids the need to group similar variable types together to ensure a consistent type /

word alignment.

For receipt and transmission of DIS format PDUs, the Model Builder application software sup-

ports DIS 2.03, 2.04, and IEEE releases of the standard.

For receipt and transmission of cell based data the format is an ASTi proprietary format. Cell data

transmitted over the network interface is bundled in a standard UDP format packet.

I/O Interface

The following sections provide interface information about all I/O cards available for the DACS.

Digital Input/Output

Connections: The digital input/output card interfaces through a male DB 37 connector as shown

in ﬁgure 14. Eight digital inputs and eight digital outputs are available.

Digital Input: The digital input port on the DI/DO board uses optically isolated sensors to sense

whether an externally applied voltage is on or off.

To sense an external voltage, connect the voltage source between a pair of input pins (for exam-

ple: High In 0 and Low In 0). The DI/DO board is conﬁgured to sense voltages between 4.1 VDC

(minimum turn-on voltage) and 15.8 VDC (damage threshold voltage). The applied voltage must

supply a current of at least 3 mA.

Digital Output: The outputs are reed relays. When an output is triggered, the A and B pins for the

output will be shorted through the reed relay. There is no polarity for these outputs. Loads of more

than 10 Watts should not be driven through these relays. Also, inductive loads such as motors

should not be driven through the relays. An overcurrent can permanently fuse the relays closed.