Perle Systems STS Digital/Relay Section, Serial Pin Signal Section, Length Channel, Length Pin

I/O UDP

Digital/Relay Section

The Digital/Relay Section of the UDP packet provides the status of Digital and Relay channels. The data for the status of each channel is represented by 1 byte, with each bit representing a channel (least significant bit format).

Note: The Digital/Relay Channel Data subsection is present in the UDP packet regardless of whether or not the IOLAN model supports Digital/Relay channels.

Length	Channel	Digital/Relay Channel Data (1 Byte, one bit for each channel)
	Enabled
2 Bytes	1 Byte		Channel 4	Channel 3	Channel 2	Channel 1

zLength—The length of Digital/Relay Section within the UDP packet (this value will always be 2 Bytes).

zChannel Enabled—This is based on the configuration of the Digital/Relay channels. The Channel Enabled field is 1 byte in least significant bit order, for each channel. If the channel is enabled, the bit is set to 1. If the channel is disabled, the bit is set to 0 (zero).

Channel Enabled (1 Byte, one bit for each channel)

Channel 4 Channel 3 Channel 2 Channel 1

zDigital/Relay Channel Data—Each bit represents a channel status, 1 for on or 0 for off (unless the channel has been configured to be inverted, in which case 0 is on and 1 if off).

Serial Pin Signal Section

The Serial Pin Signal Section of the UDP packet provides the status of the serial pin signals from the IOLAN’s serial port. Each serial pin signal (DSR, DTR, CTS, etc.) is mapped to a bit in the 1-byte data section.

Note: The Serial Pin Signal Data subsection is present in the UDP packet regardless of whether or not the serial port is configured for the Control I/O profile or the serial pin signals are enabled.

Length	Pin	Serial Pin Signal Data (1 Byte, one bit for each signal)
	Enabled
2 Bytes	1 Byte		RTS	DTR	CTS	DCD	DSR

zLength—The total length of the Serial Pin Signal Data (this value will always be 2 Bytes).

zPin Enabled—This based upon the configuration of the signal pins on the serial port. When the serial port profile is set to Control I/O and a serial pin signal(s) is enabled, the bit is set to 1. For any serial pin signals that are disabled, the bit is set to 0 (zero) and any data associated with those serial pin signals should be ignored.

Pin Enabled (1 Byte, one bit for each serial pin signal)

RTS

DTR

CTS

DCD

DSR

zSerial Pin Signal Data—1 byte with each bit being set to high (1) or low (0) for the appropriate serial pin signals.

266 IOLAN SDS/SCS/STS User’s Guide, Version 3.6