User`s manual

ManualsBrandsZ-World ManualsComputer equipmentXP8900

XP8000 Series (PLCBus

)

Z-World 530-757-3737 2

Bus Topology

A device on the PLCBus generally has one or more ports (con-

trol registers or data registers). For example, Z-World relay

boards each have one 4-bit control register. RS232 (XP8700)

boards each have one 8-bit control register and one 8-bit data

Thus, a PLCBus device has one or more port addresses. All ad-

dresses on a single bus must be unique. Each device on the bus

recognizes its own set of addresses (by PAL encoding, jumper

wiring and other forms of logic). Each board responds only

when it is being addressed.

Any PLCBus device may have an address expansion register.

This is a register that can be used to extend the address space

of the device. No Z-World expansion card has an expansion reg-

ister at present.

Addressing modes (discussed later) and address expansion reg-

isters allow you (theoretically) to build a PLCBus with millions

of devices or perhaps a few devices with millions of addresses.

Z-World expansion boards typically have one or two addresses.

Communicating with Devices on the Bus

To operate a PLCBus device, your program (running in your

controller) will read from it or write to it. The steps involved

are as follows:

0 Initially, reset the devices on the bus.

1 Select a board—or a board register—by placing its address

on the bus.

2 If the board has an address expansion register, you might

need to set its value.

3 Send data to the device or read data from the device.

How it is done

There are 8 memory-mapped registers that correspond to the 8

bus cycles determined by the 3 bus lines A1X, A2X, and A3X.

Their specific addresses depend on the controller you are using.

BUSRD0 0 0 0 Read data, cycle 0

BUSRD1 0 0 1 Read data, cycle 1

BUSRD2 0

1 0 Read data, cycle 2

BUSRESET 0 1 1 Reading this register resets the entire

PLCBus.

BUSADR0 1 0 0 Bus address, cycle 0

BUSADR1 1 0 1 Bus address, cycle 1

BUSADR2 1 1 0 Bus address, cycle 2

BUSWR 1

1 1 Write data

To place an address on the bus, write 1, 2, or 3 bytes in succes-

sion to BUSADR0, BUSADR1, BUSADR2 respectively. Whether

you write 1, 2, or 3 bytes depends on addressing modes de-

scribed below. The addressing modes allow up to 24-bit ad-

dresses, with 12-bit addresses being most typical. The address

expansion register can extend this space.

You can read up to 24 bits using the BUSRD0, BUSRD1, and

BUSRD2 cycles. You can write up to eight bits using BUSWR.

References

Please refer to

• Zilog: Z180 MPU User’s Manual

• Zilog: Z180 Serial Communication Controllers

• Zilog: Z80 Microprocessor Family User’s Manual

•Z-World: Dynamic C Data Sheet

•Z-World: PCL-AK Tech Note (101)

• Signetics: SCC2691 (UART) Data Sheet

Contents

Summary ............................................... 1

The PLCBus Concept............................. 1

Bus Topology ........................................ 2

Building Your Own ................................ 3

Relay Boards ......................................... 4

• RELAY6 (XP8300)

• RELAY8 (XP8400)

ADC Boards ........................................... 5

• A/D12

• ADC4 (XP8500)

DAC Boards ........................................... 8

•DAC2 (XP8600)

•DAC8 (XP8900)

RS232 (XP8700).................................... 12

UIO (XP8200) ....................................... 14

Stepper Motor Controller (XP8800) .... 16

IO32 (XP8100) ...................................... 20