ADLINK HSL-DO32-M-N/HSL-DO32-M-P - Manual (Page 32)

Introducing HSL 19
1.4.2 HSL Terminology
In addition to the input/output polling mechanism shown above,
here are some HSL-related syntax for your reference.
HSL Master. Master is defined as the teacher in Figure 1.9 and
1.10. The master takes charge of giving commands, including out-
put value announcements and latest input status requests.
Slave I/O Module. Slave I/O modules are defined are the students
in Figure 1.9 and 1.10. Slave I/O modules are passive compo-
nents in an HSL system. They receive commands from the
master, then respond by telling their newest input status or by set-
ting output values. The slave I/O modules may take one or two
address indexes depending on the I/O module type.
Polling Cycle. When communicating with slave I/O modules, the
master takes turn setting the output for and gathering input from
every slave module. When all slave modules are updated, a poll-
ing cycle is completed. The polling cycle infinitely repeats when
the master is working properly.
I/O Refreshing Rate. The time needed to complete an I/O updat-
ing cycle. This may also be the longest time needed for any digital
I/O channel to obtain its latest status. The refreshing rate is
decided linearly by the total number of slaves used in an HSL sys-
tem, therefore no interference occurs between any two HSL sys-
tems or PC/IPC at the same time.
Transmission Speed. May refer to the speed of digital signal
transfer or I/O refreshing rate. When referring to the speed of digi-
tal signal transfer inside the cable, the transmission speed is
known as data rate. The unit of transmission speed is bits per sec-
ond (bps). The unit of I/O refreshing rate speed is expressed in
mini-second (ms).