AEG 381 D Specifications download pdf (Page 28)

B2.2.1 Procedure

To realize synchronous communication between the PCS and programmable

controller you must:

 select the SYNC setting on the PCS,

 load the handling software into the programmable controller.

This handling software is described in the following. Of course you can also solve

these tasks differently in your software. It is only important that you keep to the

following procedure:

1. The used data area assigned to the PCS and programmable controller must

be determined in the programmable controller (e.g. 355 flag words) and com-

municated to the PCS via the AL and AM driver variables. The programmable

controller flag word area should be initialized.

2. Thereupon, the PCS sends an order number (byte-by-byte, every time incre-

mented by one) in PCS word 3, e.g.: 01. This is the signal for the programmable

controller, that the data area can be processed. Furthermore, a time-out timer

can be restarted (if this is used).

3. If the processing of the data area is finished, then the inverted sync word of

PCS word 3 is copied to the PCS word 2, e.g. with FE. This is the signal for the

PCS to access to the data area. Nothing more may be changed now in the data

area by the programmable controller program!

From now on, step 2 and 3 will be cyclically executed. If a time-out appears, then

processing is resumed with step 2 with order number 01 again.

B2.2.2 Description of the handling software

The existing handling software is required only for synchronous operation. It can

however, also be used unchanged for asynchronous operation (caution, a loss of

the programmable controller communication is not noticed in the PCS!). The data

word area is envisaged for flag word 100..355. If you want to displace the flag

word area, then you must rewrite the handling software completely.

Overview:

OB1:

Selects PB2 (PCS communication).

PB2:

Manages the communication processing. PB1 (initialization) is selected in the 1st.

cycle. If the communication fails, then PB3 is selected once. After a communication

loss the synchronizing word is examined only, if a restart input 0 → 1 transition

exists. Then, PB3 (data area processing) is selected if it is ascertained in the

synchronizing word that the PCS has sent an order (MW 102 <> MW103). After

that, the sync word processes and the time-out timer is restarted.

PB1:

Initializes the PCS command words and the time-out timer. Attach your

initializations here.

OB 1 PB 2 PB 1

PB 4

PB 3

Programmable controller handling software

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AEG 381 D Specifications Page 28

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