Beijer Electronics SCOM Protocol EN - Manual (Page 18)

Protocol Description and Timings
18 Elektronik-Systeme Lauer, MAEN976
The Lr value depends on the command, for which the response message is generated.
Detailed information and the “Maximum Lr value” for each response message can be
found in Command Reference chapter.
Example
Broadcast command response for command BRT, sent by monitor with address 7 at
9600 baud: Te = (2.5 + 9) x 10 x 8 / 9600
≈ 0.0958 s ≈ 95.8 ms
The delay time Te is inserted by the monitor automatically, only if the RS485 inter-
face is selected for the communication. If the RS232 interface is used, the response
message is generated and sent as fast as possible. This is true also for the Ethernet
communication, but the time when the response message is received depends actually
on the network load and speed.
The RS232 communication does not require a delay time due to the point-to-point
communication, where only two devices can be attached to the line (i.e. host and
monitor or monitor and monitor). Ethernet communication is similar to the RS485
communication, where many monitors can be attached to the same line. However,
in contrast to the RS485 interface, a collision is handled by the Ethernet architecture
and software, so there is no need for anti-collision support within the monitor.
Note:
The given “Maximum Lr value” is specified for a valid command. If an invalid command
with a data field exceeding the specification is sent, the Lr value will grow accordingly.
Related information
Command Reference