HNS 3000 IO-Link
page 11
Edition: 2020-04-02
HYDAC ELECTRONIC GMBH
Part no.: 669945 E
9.2 SDCI
mode
Via a connected IO-Link master the level switch can be switched to the SDCI mode
(Single-drop digital communication interface for small sensors and actuators), also known
as "IO-Link mode", by means of a wake-up signal. In this mode, Pin 4 serves as a
communication pin. The master is able to communicate with the pressure switch in order
to change parameters or to read out measured values.
The centre LED flashes.
In the SDCI mode a transmission of the process data is performed cyclically via the
communication pin 4 to the connected IO-Link master.
The HNS 3000 provides a process data width of 2 or 4 bytes, depending on the model
version, regardless if with or without additional temperature switch. 14 bits are used for
each actual measured value ("PDV" = "Process data value"). One decimal place is used
both for the fluid level and for the temperature.
2 further bits function as switching bits ("BDC" = "Binary digital channel"), which can be
parameterised just as physical transistor switches (please see
chapter
10.4Parameterisation in SDCI mode
or chapter
25Anhang / Annex: IODD
Einstellparameter / IODD Setting Parameters
).
The process bits are arranged in one or 2 data words in accordance with Table 1. In
order to receive the physical measured value for further processing in the controller, a bit
shift operation must first be carried out for each data word (shift right 2).
Table 1 - IO-Link Process data structure, arrangement of der PDV and BDC bits
sub index bit offset
data type
name
description
1
0
Boolean
BDC1
Fluid level - switching bit 1
2
1
Boolean
BDC2
Fluid level - switching bit 2
3
2
14-bit UInteger PDV1
Process value 1 = Fluid level
4
16
Boolean
BDC3
Temperature – Switching bit 3
5
17
Boolean
BDC4
Temperature – Switching bit 4
6
18
14-bit Integer PDV2
Process value 2 = Temperature
The figures below show the arrangement and the order of the bits and octets for the
version with a temperature sensor:
Octet 0 and 1
Octet 0
bit
offset
31 30 29 28 27 26 25 24
sub index
6
element
bit
13 12 11 10 9 8 7 6
Octet 1
bit
offset
23 22 21 20 19 18 17 16
sub index
6
5
4
element
bit
5 4 3 2 1 0
