Hardware Setup

PCD Family of PLCs

The Saia PCD (Programmable Control Device) is a family of PLCs which are programmed with the same instruction set. All PLCs in the family have 8192 flags, 1520 timer counters and 4096 registers.

• PCD2 - This is the economy PLC which allows up to 128 I/O points, has up to 160kb of memory and up to 4 serial interfaces.

• PCD4 - This is the midrange PLC which allows up to 512 I/O points, has up to 428kb of memory and up to 4 serial interfaces.

• PCD6 - This is the deluxe PLC which allows up to 5120 I/O points, has up to 1MB of memory and up to 28 serial interfaces. This PLC also allows multi processors.

PCDs Setup

Set your PCD to the communication setting you want. The default hardware settings for the PCD are as follows:

These settings are recommendations only. If you use the Communications Express Wizard, these default settings are configured in your project automatically, though your hardware may support other values. If you do set the baud rate, data bits, stop bits or parity to another value, you must manually set the new value(s) in your project.

Note: This protocol can use two different transmission methods:
1) Parity changing method
2) Break method of transmission.
The Plant SCADA SBUS driver uses as default the parity changing method. Run the SAIA PCD Programming Utilities to set the the transmission method.

PCD6 Hardware Configuration Example

A basic configuration of the PCD6 is as follows:

PCD6-M540Single processor module with 4 serial interfaces.
PGU, RS232 connection for the programming unit.
Port 1, RS422 or RS485 for point to point or SAIA bus connection.
Port 2, RS232 connection for a modem.
Port 3, 20mA current loop.

PCD7-R210Memory module with 64k RAM and real time clock, or ...

PCD7-R220Memory module with 256k RAM and real time clock.

PCD6-N100D4Power supply unit.

PCD6-C100Rack unit (card cage).

SAIA bus cableRS422 cable for connection to the PC.

PGU cableRS232 cable for the programming interface.