ISOLGUARD HIG93, HIG93/L, HIG94
V5.8/23
HAKEL spol. s r.o. Hradec Králové
www.hakel.com
Page 13 / 15
RS485 bus termination on the MDS-D is done by a switch available inside the case. The switch labelled SWITCH1 connects
terminating resistance 120 Ω to internal RS485 line (A1 B1) in the ON position. The switch labelled SWITCH2 connects
terminating resistance 120 Ω to external RS485 line (A2 B2) in the ON position.
8. Data transmitted via RS485 bus
HIG93, HIG93/L, HIG94 devices communicate on the RS485 bus by using the ISOLGUARD communication protocol. This
protocol was designed by HAKEL as a universal command system for reading data from insulation monitoring devices of
HIG9x series and additional products.
ISOLGUARD communication protocol differentiates between 3 basic transmitted data types:
Identification data, through which the device displays its type designation
Measured data, information on currently measured quantities and their status
Device parameters, that contain the device settings values
For identification data, the unit sends the codename of its design, the software version and program compilation date - which
is not the date of device’s production.
Measured data and parameters are sent in individual information blocks. Each information block contains the alphanumeric
name, numerical value and units in which the value is sent. In addition, a character is added to the measurement data,
determining the status of this measurement (e.g., fault occurrence). Parameter data are extended of priority character,
determining the importance of the set parameter. This character divides parameters up into eight groups, when in group no. 1
are the most important and necessary parameters for the proper functioning of the device (e.g., critical limits) and group no. 7
is the least important parameters. Parameters with priority no. 0 are operating parameters serving to inform additional HAKEL
devices and should be ignored by the user application.
The meaning of each character and the correct form of the protocol commands are described in the ISOLGUARD
Protocol Programming Manual. Data that can be read from the HIG93/94 using this protocol are listed in the tables
below.
Measurement data
Quantity
Symbol
Value (e.g.)
Units
Insulation resistance
Risol
500
k
Ω
Table 4: Measurement data transmitted via ISOLGUARD bus
Parameters data
Parameter name
Symbol
Value (e.g.)
Units
Priority
Critical limit of insulation resistance 1
Rcrit1
50
k
Ω
1
Critical limit of insulation resistance 2
Rcrit2
100
k
Ω
1
Device address on the RS485 line
485ADDR
1
-
1
Insulation resistance hysteresis
Rhyst
50
%
2
Using the fault memory function
FA.MEM
1 = switch on
0 = switch off
-
2
Delay in response of signalling
the insulation resistance fault
tON
0
sec
3
External inductor resistance
Rtl.ext
12,3
k
Ω
3
Delay in device test start
tTEST
6
sec
4
Temperature inside the HIG module
mTEMP
32
°C
4
Connection of terminating resistance
485Rte
1 = connected
0 = disconnected
-
0
Table 5: Parameters data transmitted via ISOLGUARD bus
