Specifications

The used AEG120DR driver is a direct driver, i.e. it replaces directly the data words

between the programmable controller and the PCS. Either a small or no

programmable controller program is required for that resulting only in a small

scan time burden for the programmable controller. Using the BKOS protocol, the

programmable controller and the PCS communicate via RS-232C with 9600 bauds,

8 bits, ODD parity and 1 stop bit. It is possible to run a synchronous or asynchronous

communication operation since only the exact data words which are absolutely

necessary are replaced.

SYNC or NOSYNC?

Since the data interchange occurs asynchronously by writing and reading via

several programmable controller cycles, the data written by the programmable

controller can be overwritten by the PCS and conversely. Thus, there is no data

consistency. Possible solutions are either a strict separation of read and write data

words (→ NO SYNC) or the usage of a synchronization word (→ SYNC). The usage

of a synchronization word enables the application of a time-out timer on the PCS

side.

DETERMINE THE DATA AREA

A common data area must be defined to enable access of the programmable

controller and the PCS. This must be physically available and defined in the

programmable controller.

In the PCS, this area is defined via the AL and AM driver variables. If this area in

the programmable controller is selected as too small then a time-out can appear

during the operation!

EFFECTIVE RESPONSE TIMES: PCS - PROGRAMMABLE CONTROLLER

The response time of the protocol depends extensively on the tasks executed in the

PCS. If variables are displayed or even processed, then the communication cycle

time is essentially higher than with text without variables. Also, the transfer of the

message bit area and LED words influences this time. Limit these transfers.

The number of sub-packages in the AJ driver variables can be limited to enable a

frequent transfer of the keys. The disadvantage thereby is, that the reading and

writing of variables require more time.

Summing up, the key → LED time can be between 0.5 ms and 3 seconds.

Programmable controller handling software

B2.Programmable controller handling software