Bit write methods

PLC (Programmable Logic Controller) Bit Write

For PLC-5 devices, the AVEVA Enterprise SCADA driver allows you to configure an abdf1 record to use the PLC Bit Write method to send a write message (function code 0x02) to the field device. Upon receiving the command, the field device performs a bit write operation in a single step.

Note: Not all DF-1 devices support this operation.

PLC Native

For PLC-5 devices, the PLC Native bit write method sends the read-modify-write (function code 0x26) command. For SLC 500 devices, the driver uses the function code 0xAB for a masked bit write.

Host Read-Mask-Write

For a digital or multi-state command, you can configure an abdf1 record to read, modify a bit in the cached value, and then write the value back to the field device.