OMRON Isgus - SmartRelay 3 system

Signal description

An OMRON interface uses the following standardised signals:

Signal

Meaning

Explanation

SREL.ADV connection

SREL3 ADV connection

SREL AX Classic connection

DATA

Data

F1 ("D0")

O1

Output 1

CLK

Clock

F2 ("D1")

O2

Output 2

CLS

Card loading signal

Optionally configurable

F3 (“LED/buzzer/input1”)

O3

Not available

All outputs are open-drain. A pull-up resistor (1kΩ to 10kΩ type) and the positive power supply (3 VDC to 24 VDC ) must be provided for signal lines.

The signals are “Active low”. The data becomes valid on the falling edge of the CLK signal.

Signal timing

Time

Description

Min.

Typ.

Max.

Unit

t CLS-

Time between activation of the CLS signal and first data bit

8

12

20

ms

tCLK

Clock period

290

320

350

µs

tS

Set-up time for data bit

50

100

150

µs

tC0

Clock set to “low” level (clock low)

50

100

150

µs

t CLS+

Time between last data bit and deactivation of the CLS signal

8

12

20

ms

Data format (OMRON Isgus)

Each message below consists of a sequence of letters ("characters").

Each “character” is represented by a sequence of 5 bits (BCD code + parity):

Data structure of a message:

S BBBB M AAAA E L

Meaning:

S

Start character (hex B)

B

User ID number (0 to 9,999)

M

5th digit of the user ID number

A

Facility code (0 to 9,999)

E

End character (hex F)

L

Longitudinal parity check character (over all transmitted characters XOR[S...E])