Delta Tau Universal PMAC Lite, Hardware Reference Manual

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Universal PMAC Lite
Introduction 5
Due to bus drive limitations, a limit of four with an absolute maximum of six expansion port (JEXP)
accessories is recommended on any PMAC. In addition, the address spaces for Acc-14D/V and Acc-36P/V
boards on the JEXP expansion port are limited to six. One Acc-14D/V occupies a full address space; four
Acc-36P/V boards occupy one address space.
JTHW Thumbwheel Multiplexer Port Accessories
A total of 32 boards can be plugged into the thumbwheel multiplexer port (JTHW).
The Acc-27 Opto-Isolated I/O board cannot be used with any other accessory that connects through the
thumbwheel multiplexer port (JTHW): the Acc-8D Opt 7 R/D converter (if absolute power-on position is
desired); the Acc-8D Opt 9 Yaskawa Encoder Interface, the ACC-18 thumbwheel board, or any of the Acc-
34 family of serial I/O boards. This is because the Acc-27 uses the port in non-multiplexed fashion.
There is a limit of 256 addresses for multiplexed accessories on the JTHW thumbwheel multiplexer port:
the Acc-8D Opt 7 R/D converter (if absolute power-on position is desired); the Acc-8D Opt 9 Yaskawa
Encoder Interface, the Acc-18 thumbwheel board, or any of the ACC-34 family of serial I/O boards.
An Acc-8D Opt 7 board occupies one address.
An Acc-8D Opt 9 board occupies one address.
An Acc-18 board occupies eight consecutive addresses, starting with an address divisible by 8.
An Acc-34 type board occupies eight consecutive addresses, starting with an address divisible by 8.
There are no known cases of anyone using all of these address spaces.
JPAN Control Panel Port Accessories
The Acc-16D control panel and the Acc-39 handwheel encoder converter cannot be used on the same
PMAC because both use the entire JPAN control panel port.
JDISP Display Port Accessories
Only one display can be connected to the JDISP display port. This includes any of the Acc-12 family of
displays, and the built-in display in the Acc-16D control panel.
JSx Port Accessories
Each Acc-28 A/D converter board must interface to a separate DSPGATE gate array IC on PMAC or Acc-
24P/V through its JSx connector. Therefore, the limitations on numbers of Acc-28s for a PMAC are as
follows:
PMAC Lite; no ACC-24P/V 1 ACC-28
PMAC Lite; ACC-24P, no Opt 1 2 ACC-28s
PMAC Lite; ACC-24P with Opt 1 3 ACC-28s
Resistor Pack Configuration
Termination Resistors
The PMAC Lite provides sockets for termination resistors on differential input pairs coming into the board.
As shipped, there are no resistor packs in these sockets. If these signals are brought long distances into the
PMAC Lite board and ringing at signal transitions is a problem, SIP resistor packs may be mounted in these
sockets to reduce or eliminate the ringing. All termination resistor packs are the type that has independent
resistors (no common connection) with each resistor using two adjacent pins. The following table shows
which packs are used to terminate each input device:
Device Resistor Pack Device Resistor Pack
Encoder 1 RP51 Encoder 3 RP53
Encoder 2 RP52 Encoder 4 RP54