Instruction Manual

4.5 ALLEN-BRADLEY COMMANDS

The Allen-Bradley commands used by the PCS interface application are summarized in Table 4-1

as follows:

Table 4-1. Allen-Bradley Commands Used

Function Command

Code

Title

Read 01 Unprotected Read

Write 00

Protected Write

Unprotected Write

Initialization (Sets maximum

ENQS, NAKS, and timeout of

network interface.)

06 Set Variables

RS-232/485 ITB, J1 ALLEN-BRADLEY

(FEMALE DB-9 (MALE/FEMALE, DB-25/15

CABLE END) CABLE END)

RxD (IN) 2 2 TxD

TxD (OUT) 3 3 RxD

GND 5 7 GND

74 RTS

85 CTS

Figure 4-4. RS-232/485 ITB J1 to Allen-Bradley PLC Cable

Section 4. Allen-Bradley Mode

ALLEN

4-3