ISOLGUARD HIG93, HIG93/L, HIG94
V5.8/23
HAKEL spol. s r.o. Hradec Králové
www.hakel.com
Page 12 / 15
MASTER
485Addr=0
DIP SW1 =ON
485Rte=No
485ADDR=1
485Rte=YES
(Rte = 120Ω)
485ADDR=3
MENU
Parameter:
485Rte=No
485ADDR=2
MDS-D/66
A1 B1 SH1
B2 SH2
(+)
(-)
A2
1
2
3
4
5
6
7
8
Napájení
MDS-D
24 V DC
HIG93
RS485
HIG94
RS485
HIG93
RS485
Externí linka RS485
Picture 7: RS485 bus
Picture 8: RS485 ISOLGUARD
bus
HIG93
MASTER
120Ω
Pull-Up
∻
470Ω 1kΩ
Pull_Down
∻
470Ω 1kΩ
A
B
station 1
HIG93
A
B
station 2
HIG94
A
B
station 3
HIG94
A
B
station n
+5V
A
B
Rte=YES
ADDR = 0
7. Communication protocol
Units HIG93, HIG93/L and HIG94 communicates via the industrial RS485 bus using the protocol based on the PROFIBUS
protocol. Communication proceeds in the request – response mode. One MASTER station has to be connected to the bus,
whereas this MASTER station sends requests to the other SLAVE stations. The slave stations only respond to requests, they
never start communication. Unit HIG93/94 is in position of the slave station.
Individual stations are connected with TWISTED PAIR-TP. One conductor is labelled A, the second one B. Logical 1
(respectively 0) is determined by the voltage between these conductors. During an idle state (logical 1), the A conductor is
more positive than the B conductor (at least by 200mV).
An individual address must be set for each station being connected to the bus. The address for the unit HIG93/94 is adjustable
within a range 1 to 126 (address 0 is reserved for the MASTER station).
The length of the line can be up to 1200 meters; in view of proper installation, both ends of the line need to be terminated,
namely by using the resistance of 120 Ω. At a given moment, each station connected to the line RS485 may transmit or
receive. This mode is called half-duplex. In order to avoid any collision (i.e., two stations must not transmit simultaneously),
the transmit right must be assigned by the MASTER station. In practice, the communication proceeds in such a way, that the
MASTER station sends requests subsequently to all connected units and the SLAVE stations response. The accessibility of
the station is ensured by its address, which must be unique for every station on the line.
For ISOLGUARD system PC computer or programmable logic controller with RS485 line can be used as a MASTER station.
Also, remote monitoring module MDS-D/66 with protection degree IP66 from HAKEL production may be used. This module
allows remote displaying of measured values and set parameters and also data transferring to the user’s master system.
Detailed description of HIG93/94 communication protocol is given in the programming manual.
RS485 ISOLGUARD
line parameter setting
In the menu
Parameter settings
may be selected the menu
Set 485ADDR
and
Set 485Rte
.
Menu
Set 485ADDR
serves for setting of the address for HIG93/94 device on the RS485 bus. The setting range for the address
is 1 to 126.
Menu
Set 485Rte
serves for setting the connection of an internal terminating resistor R
te
to the RS485 line. This parameter
may be set to
YES
(when the resistance 120Ω is internally connected to the RS485 line of the module), or
NO
(without
connected resistance).
RS485
bus structure
Communication between HIG devices and MDS-D remote monitoring module
Using MDS-D as the MASTER station allows the user smooth and convenient supervision of up to 24 IT power supply systems’
status, monitored by HIG93/94 devices or other devices of HIG ISOLGUARD series. MDS-D/66 touch panel in industrial design
with protection degree IP 66 communicates with insulation monitoring devices via ISOLGUARD protocol fully automatically,
including the ability to search monitoring devices on the connected bus. For proper function it is only necessary to set unique
addresses in the device menu and connect monitoring devices and MDS-D/66 panel by twisted pair. HIG monitoring devices
are always connected to the internal RS485 line of the MDS-D module, i.e. A1 B1 terminals.
