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

SCANport Data Link

A data link is a pointer used by some SCANport devices to transmit information to a drive.

The data link allows parameter values to be written when sending logical commands and references to the drive. The data link also allows parameter values to be read when reading logic status and feedback.

SCANport devices that support this feature have a set of parameters for data link configuration.

These are called the ‘data link input’ and ‘data link output’ parameters.

The Datalink feature is enabled by setting the correct switch on the communication module SW3 to ‘Enable’ and configuring the ‘Datalink Input’ and ‘Datalink Output’ parameters in the SCANport device.

Each datalink consists of two 16-bit input words and two 16-bit output words.

By setting the two ‘Datalink In’ (data link input) and ‘Datalink Out’ (data link output) parameters in the SCANport device

Set the two ‘Datalink In’ parameters for this data link to the desired target parameters.

Similarly, by setting the two ‘Datalink Out’ parameters, each of the two output words can be configured to Similarly, the

Each of the two output words can be configured by setting the two ‘Data Link Output’ parameters for that Datalink.

Each Datalink switch on SW3 enables or disables one Datalink.

If a Datalink is enabled, the parameter values set in the ‘Data Link Output’ parameter will be transmitted to the communication module.

The parameter values set in the parameter will be transmitted to the communications module, and the data sent by the communications module for that datalink will be transferred to the parameters set in the ‘Data Link Output’ parameter.

If the data link is enabled, the parameter values set in the ‘Datalink Out’ parameter will be transferred to the communication module.

and the data sent by the communication module for the data link will be transmitted to the ‘Datalink In’ parameter.

If the data link is not enabled If the data link is not enabled, the data transmitted to the SCANport device for this data link will be zero.

The data transmitted to the SCANport device will be zero and the communication module will ignore any data sent by the SCANport device.

The communication module will ignore any data sent by the SCANport device.

If the ‘Data Link Input’ parameter is not configured for an input word, that input word will be ignored.

If the ‘Datalink Out’ parameter is not configured for the output word, the output word will be undefined. The output word will be undefined (usually set to zero).

The datasheet has up to eight areas, each with a different purpose.

1. parameter value read or write. Reading data from a file in this area will cause the communications module to read parameter values from the SCANport device, to

and send these values as a response to the read message. Writing data to a file in this area will cause the communications module to write data to the SCANport device's parameters.

Parameter.

2. the status of the last time the parameter was written. This area is read-only. When read, the data returned will contain information about the status of the last parameter write performed by the communications module.

If no errors occurred during the write, all data returned will be zero. The area is read from element number 0.

3. Parameter Read Full. This area is read-only. When read, the returned data contains 20 words (40 bytes) of information for each parameter, including the scaling, parameter text, and parameter name.

The data returned when read contains 20 words (40 bytes) of information for each parameter, including scale, parameter text, unit text, minimum value, maximum value, and default value. When reading this area, set the number of elements to 20 times the number of parameters to be read. 4.

4. block transfer simulation area. This area provides a method of sending and receiving SCANport information to and from the SCANport device.

This allows the user to execute all SCANport commands supported by the device.

The structure of this data table is the same as the block transfer data table for the 1203-GD1. GK1. and GM1 RIO communication modules.

To send a SCANport message, write data to this area starting with element number 0. Allow the SCANport device enough time to respond to the message and then read the data.

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.