How does the A-B Communication Module communicate with serial devices?

Then read the response message from this area starting with element number 0.

5. producer/consumer emulation area. Each element in this area has a different function.

- Logical Command/Status. Logical commands are sent to the driver when writing.

Reading provides the logical status of the SCANport device.

- Reference/Feedback. Sends a reference to the SCANport device when writing. Read provides feedback from the SCANport device. The meaning of the reference and feedback values depends on the type of SCANport device.

- DataLink A1. a value is sent to the parameter pointed to by the DataIn A1 parameter of the SCANport device when writing to Datalink A1.

Reads from Datalink A1 the value of the parameter pointed to by the DataOut A1 parameter of the SCANport device.

- Datalink A2 to Datalink D2 have the same function as Datalink A1.

6. communication module parameters. All four elements in this area can be read or written to and affect the operation of the communication module as follows:

- ENQ Quantity. The number of ENQs sent before the module gives up on receiving an ACK or NAK. (Default = 3)

- NAK Count. The number of times the module resends the message if the reply is always NAK. (default = 3)

- Message Timeout. The number of milliseconds the module waits before sending an ENQ. (default = 100 milliseconds)

- Application Timeout. The number of seconds the module waits between sending messages before failing the connected SCANport device. (Default value is set by the Configuration DIP switch)

7. reserved for future expansion. If an attempt is made to read or write any address in this area, the communications module will respond with an error message.

8. system area. Reading from this area will cause the communications module to respond with a 22-character string.

This string is set at power-up to a product text string containing the SCANport device with ‘/1203’ appended.

Writing to this field will change the characters contained in the string. After a power failure, the string will revert to the original text.