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I/O Controller 2 Manual HW group
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NVT control examples
Most NVT commands have a fixed length. So, for example, if a value has a 4-byte format, and the
current setting can be read by “setting” a value of 0, this zero needs to be sent as 00 00 00 00 hex.
Setting the output byte
This command sets the output port to AA (10101010 bin).
< IAC >< SB >< COM_PORT_OPTION >< CAS_SET_GPIO ><(byte to output)>< IAC >< SE >
FF FA 2C 33 AA FF F0
As a response, the following sequence confirms the port settings:
< IAC >< SB >< COM_PORT_OPTION >< ACS_SET_GPIO ><(byte to output)>< IAC >< SE >
FF FA 2C 97 AA FF F0
Reading the inputs
Request for the input value (XX) at GPIO.
Outgoing sequence: FF FA 2C 32 00 FF F0
I/O Controller returns: FF FA 2C 96 XX FF F0
Reading the outputs
Request for the current value (XX) of the output register that controls the output pins.
Outgoing sequence: FF FA 2C 32 30 FF F0
I/O Controller returns: FF FA 2C 97 XX FF F0
Resetting the D5 output
Request to set one output bit to logic LOW, without changing other output bits.
Outgoing sequence: FF FA 2C 32 25 FF F0
I/O Controller returns: FF FA 2C 97 DF FF F0
where DF is the actual output port value (also depends on the previous port state). I/O Controller
changes only one bit but the response contains the entire port value.
Input state change notification
Unsolicited notification that reports a change at the inputs of the I/O Controller through an established
TCP connection.
It can start with the FF FA 2C 32 00 FF F0 sequence
– see the more detailed
description.
Outgoing sequence: none
I/O Controller sends: FF FA 2C 34 XX FF F0
where
XX is the current value at the input port.
Note: The function works similarly to the incoming serial port data. Thus, in the TCP
Client/Server mode (IP address of the remote side is specified) with NVT
enabled, the device attempts to establish a connection and send the input
change information whenever a single byte of serial data is received or any
digital input changes. After establishing the TCP connection, only the current
input state is sent, NOT the whole history of changes (while the connection was
closed).