hakel ISOLGUARD HIG93 User manual

ISOLGUARD HIG93, HIG93/L, HIG94 V5.8/23
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Insulation monitoring device
ISOLGUARD HIG93, HIG93/L, HIG94
Operating instructions
Document’s name: DOK-70915-V5.8

ISOLGUARD HIG93, HIG93/L, HIG94 V5.8/23
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Content
1. ISOLGUARD INSULATION MONITORING DEVICES HIG93, HIG93/L, HIG94 ............................................................................. 3
1.1 VARIANTS OF DEVICES ISOLGUARD HIG93, HIG93/L, HIG94 ......................................................................................... 3
1.2 BASIC CHARACTERISTICS ................................................................................................................................................. 3
2. ISOLGUARD HIG93, HIG93/L, HIG94 TECHNICAL CHARACTERISTICS................................................................................... 4
3. HIG93, HIG93/L, HIG94 CONTROLS AND CONNECTING TERMINALS ......................................................................................... 5
4. RECOMMENDED CONNECTION OF HIG93, HIG93/L, HIG94 TO THE MONITORED IT POWER SUPPLY SYSTEM ................................ 7
5. INFORMATION ON THE DISPLAY .............................................................................................................................................. 8
5.1 DISPLAYED INFORMATION HIG93, HIG93/L, HIG94 .......................................................................................................... 9
6. INSULATION RESISTANCE FAULT EVALUATION ........................................................................................................................ 11
7. COMMUNICATION PROTOCOL .............................................................................................................................................. 12
8. DATA TRANSMITTED VIA RS485 BUS ................................................................................................................................... 13
9. HIG93, HIG93/L, HIG94 PARAMETERS FACTORY SETTINGS ................................................................................................. 14
10. DEVICE DIMENSIONS ..................................................................................................................................................... 14
11. DEVICE INSTALLATION.................................................................................................................................................... 15
12. MAINTENANCE AND SERVICE .......................................................................................................................................... 15
13. PRODUCER................................................................................................................................................................... 15
Picture list
Picture 1: Terminals designation ............................................................................................................................................... 5
Picture 2: Connection of HIG93/94 device ................................................................................................................................ 7
Picture 3: Connection of HIG93/94 device ................................................................................................................................ 7
Picture 4: Displayed information ................................................................................................................................................ 8
Picture 5: Insulation resistance fault evaluation ...................................................................................................................... 11
Picture 6: Insulation status fault evaluation with time tON or hysteresis zero value .................................................................. 11
Picture 7: RS485 bus .............................................................................................................................................................. 12
Picture 8: RS485 ISOLGUARD bus ........................................................................................................................................ 12
Picture 9: Device dimensions .................................................................................................................................................. 14
Tables
Table 1: Variants of devices ...................................................................................................................................................... 3
Table 2: HIG93, HIG93L, HIG94 technical characteristics, part 1 ............................................................................................. 4
Table 3: HIG93, HIG93L, HIG94 technical characteristics, part 2 ............................................................................................. 4
Table 4: Measurement data transmitted via ISOLGUARD bus ............................................................................................... 13
Table 5: Parameters data transmitted via ISOLGUARD bus ................................................................................................... 13
Table 6: Factory values of device’s parameters ...................................................................................................................... 14
Used symbols
Warning, caution
This symbol informs about very important installation and operation instructions of the device or about
hazardous situations that may happened during the installation and the operation.
Information
This symbol highlights particularly important characteristics of the device.
Note
This symbol indicates useful additional information.

ISOLGUARD HIG93, HIG93/L, HIG94 V5.8/23
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1. ISOLGUARD Insulation monitoring devices HIG93, HIG93/L, HIG94
The insulation monitoring devices HIG93, HIG93/L, HIG94 produced by HAKEL for the ISOLGUARD series are designed for
monitoring the insulation status of single-phase and 3-phase ungrounded IT power supply systems that are designed and
operated according to standards IEC 61557-1:2007, IEC 61557-8:2014, HD 60364-4-41:2017.
Devices enable monitoring of single-phase and 3-phase ungrounded IT power supplies systems up to the maximum operating
voltage 275V AC, eventually 3x275V AC. If insulation status monitoring of a single-phase or 3-phase ungrounded IT power
supply system with higher operating voltage is required, it is necessary to create an artificial centre using TL inductors produced
by HAKEL. Such a created centre is connected to the terminal of insulation monitoring device HIG93, HIG93/L or HIG94.
Insulation monitoring devices enable to display the numeric value of the measured insulation resistance, then there are buttons
for setting device parameters and signalling LED diodes to display the status of monitored power supply system and of the
device. To the insulation monitoring device, it is possible to connect MDS-D series remote monitoring modules to monitor the
power supply system status, which are produced by HAKEL.
HIG93, HIG93/L and HIG94 devices are equipped with ISOLGUARD RS485 communication line and can communicate with
a master computer via industrial RS485 bus with the protocol based on the PROFIBUS protocol. Description of the
communication protocol is available on request.
Two inbuilt signalling relays with switching contacts enables alarm signalling for two independently set values of critical
insulation resistance. The insulation monitoring device has an optional alarm memory function with the possibility to terminate
the alarm using the button on the device. Local and remote testing of the insulation monitoring device function can be done.
Only one insulation monitoring device can be connected to the same ungrounded IT power supply
system.
1.1 Variants of devices ISOLGUARD HIG93, HIG93/L, HIG94
Type Display
Menu
Signalling
relay 1
Signalling
relay 2
Range of
displayed
value
Critical insulation
resistance
Communication
bus bar
MDS-D
connection
Device type
according to
IEC 61557
-
8
SW
HIG93
Yes 1x SPDT 1x SPDT
5 kΩ to 900 kΩ
Adjustable
5 kΩ to 300 kΩ
RS485
ISOLGUARD Yes
V5.8
Art. no. 70 915
HIG93/L 0,1 kΩ to
90 kΩ
Adjustable
0,1 kΩ to 90 kΩ
Art. no. 70 915/L
HIG94 200 kΩ to
5 MΩ
Adjustable
200 kΩ to 900
kΩ
Art. no. 70 917
Table 1: Variants of devices
Notes: SPDT signalling relay with one switching contact
MDS-D remote monitoring module of HIG series devices, with display and communication via ISOLGUARD RS485 line
HIG93, HIG93/L, HIG94 complies with standards:
 HD 60364-4-41:2017 Low-voltage electrical installations- Protection against electric shock
 IEC 61557-8:2014 Insulation monitoring devices for IT systems
 IEC 61557-1:2007 Equipment for testing, measuring or monitoring of protective measures
 IEC 60664-1:2007 Insulation coordination for equipment within low-voltage system - Principles, requirements and tests
1.2 Basic characteristics
 Insulation monitoring device of AC systems with 0 to 275 V voltage without additional devices, for greater voltages
additional inductor is needed
 Display of the measured insulation resistance Risol in the range 0,1 kΩ to 90 kΩ, 5 kΩ to 900 kΩ or 200 kΩ to 5 MΩ
 Two insulation resistance status signalling relays equipped with switching contact
 Connection to ISOLGUARD RS485 bus, insulation strength 2500 Vrms against the internal circuits and network circuits
 Optional memory of the invoked alarm with possibility to unlock by button on the device
 Option to set two values of monitored insulation resistance Rcrit1 and Rcrit2 using the display and push-buttons, namely in
the range 0,1 kΩ to 90 kΩ, 5 kΩ to 300 kΩ or 200 kΩ to 900 kΩ according to the device type
 Adjustable hysteresis of the insulation resistance limit value in the range 0 to 100 % using the display and push-buttons
 Adjustable delay in signalling relay response tON in the range 0 to 60 seconds using the display and push-buttons
 Access to the device settings with the pushbuttons can be locked. Unlock by a button combination.
 Separate supply voltage also allows to monitor IT power supply system, which is not under voltage
 2M (36 mm) module width for assembling on DIN rail 35 ed. 28.7.2020
AC

ISOLGUARD HIG93, HIG93/L, HIG94 V5.8/23
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2. ISOLGUARD HIG93, HIG93/L, HIG94 technical characteristics
Type HIG93 HIG93/L HIG94
Monitored IT power supply system type AC
Maximum IT power supply system operating voltage
(without external inductor) Un 275 V∼
Nominal supply voltage Us 230 V∼
Supply voltage range 90 to 265 V∼ (47 ÷ 63 Hz) or 90 to 370 V⎓
Power consumption P max. 5 VA
Measuring circuit
Measuring voltage UM 12 V DC
Measuring current IM < 0,6 mA
Alternating internal resistance of the measuring input Ri > 2 MΩ
Displayed value's range Risol 5 kΩ to 900 kΩ 0,1 kΩ to 90 kΩ 200 kΩ to 5 MΩ
Measurement accuracy 5 kΩ ... 10 kΩ
10 kΩ ... 900 kΩ 2 kΩ
± 10 %
Measurement accuracy 0,1 kΩ ... 10 kΩ
10 kΩ ... 90 kΩ 0,2 kΩ
± 10 %
Measurement accuracy 200kΩ … 1MΩ
1MΩ … 5MΩ ± 10 % ± 15 %
Critical insulation resistance Rcrit1,
Rcrit2
adjustable
5 kΩ to 300 kΩ
adjustable
0,1 kΩ to 90 kΩ adjustable
200 kΩ to 900 kΩ
Monitored insulation resistance hysteresis Rhyst adjustable 0 to +100 % Rcrit
Delay in response of signalling tON adjustable 0 to 60 sec
Outputs
Two signalling relays with switching contact
electric strength to the internal circuits
electric strength to the supply circuits
250 V AC / 1 A
3750 Vrms
3750 Vrms
Communication line: RS485 type MASTER-SLAVE,
9600 Bd, even count parity
Insulating strength to the internal circuits and to the
network circuits
Yes
2500 Vrms
Yes
2500 Vrms
Yes
2500 Vrns
General data
Degree of protection according to IEC 60529 front panel IP40
covers except front panel IP20
Weight m 160 g
Housing material PA – UL 94 V0
Method of assembly on 35 DIN rail
Recommended section of the connected conductors S 1 mm2
Article number 70 915 70 915/L 70 917
Table 2: HIG93, HIG93L, HIG94 technical characteristics, part 1
Operating conditions
Operating temperature
Storage temperature
Shipping temperature
-10 °C ~ +60 °C
-25 °C ~ +70 °C
-25 °C ~ +70 °C
Altitude Up to 2000 m a.s.l.
Protection class II according to IEC 61140:2016
Electromagnetic compatibility IEC 61326-2-4:2012
Overvoltage category III, according to IEC 60664-1:2007
Pollution degree 2, according to IEC 60664-1:2007
Working position any
Operation type permanent
Table 3: HIG93, HIG93L, HIG94 technical characteristics, part 2
Measuring principle
DC voltage 12 V. Plus pole connected to a CENTRE terminal.

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3. HIG93, HIG93/L, HIG94 controls and connecting terminals
Green indicator lamp ON
This control lights up when the device is ON (powered). It glimmers slightly after module
activation.
Yellow indicator lamp FAULT1
The light indicates FAULT1, when the measured insulation resistance value is lower than the
set critical resistance Rcrit1 value. It even lights after the fault status removal, if the fault
memory function is active. At the same time, this status is signalled by the FAULT1 relay
contacts.
Yellow indicator lamp FAULT2
The light indicates FAULT2, when the measured insulation resistance value is lower than the
set critical resistance Rcrit2. It even lights after the fault status removal, if the fault memory
function is active. At the same time, this status is signalled by the FAULT2 relay contacts.
Display
It serves to display the measured values, to show current function of the S1 – S3 pushbuttons,
to set the parameters and to display information. For description of displayed information,
see chapter Information on the display, page 8.
FAULT1 or FAULT2 relay status change, eventually starting and ending device test, is
signalled by short display flash.
The display goes off if no button is pressed for 5 minutes and is again restored by pressing
any button. The insulation monitoring device is operational even if the display is not active.
Left push-button S1
This is a module control button whose meaning in each menu is shown on the display. When
the insulation resistance Risol is displayed, this button has the meaning of TEST push-button.
See chapter Information on the display, page 8.
Middle push-button S2
This is a module control button whose meaning in each menu is shown on the display. It releases the relay FAULT, when the
fault memory function is active. It activates display of temperature inside the module if the insulation resistance value Risol is
displayed.
Right push-button S3 MENU
This is a module control button whose meaning in each menu is shown on the display. When the insulation resistance Risol is
viewed, it activates the parameter setting menu.
Within the parameters setting menu, the prolonged pressing of this push-button terminates the data entering with memorizing
the new value, whereas the short pressing of this push-button causes exit from the menu without memorizing the new
parameter value.
Terminals A1, A2
These terminals serve to connect the module’s power supply. The power supply voltage is 90 to 265 V AC (47 ÷ 440 Hz) or
90 to 370 V DC.
Terminals CENTRE, PE
Input terminals for the insulation resistance measurement, see recommended connections of the insulation monitoring device.
If the monitoring of IT power supply system with voltage higher than 275 V AC (without brought-out neutral conductor) is
required, it is necessary to create an artificial centre using TL inductors. Such a created neutral is connected to the CENTRE
terminal. The value of external inductor DC resistance is set within the Parameters setting menu.
Terminals of the signalling relay FAULT1 230 V AC /1 A
Terminals of the signalling relay FAULT2 230 V AC /1 A
Potential-free switching relay contact for signalling the status of the monitored IT power supply system.
FAULT1 and FAULT2 relay status when insulation status fault occurs is determined by the setting of Set Relay FA parameter.
This parameter can be set to one of two values N/C and N/O.
The signalling is performed as follows when parameter Set Relay FA is set to N/C value:
Relay FAULT1 (FAULT2) is released, when the device is connected to the power supply, is functional (the indicator lamp ON
glimmers slightly) and insulation status fault FAULT1 (FAULT2) is not indicated. The insulation resistance of the monitored
system is higher than the set critical value Rcrit1 (Rcrit2).
The signalling is performed as follows when parameter Set Relay FA is set to N/O value:
Relay FAULT1 (FAULT2) is released, when the device is connected to the power supply, is functional (the indicator lamp ON
glimmers slightly) and insulation status fault FAULT1 (FAULT2) is indicated.
A
B
SH
RS485
CENTRE +12V A1 A2 PE TEST
MENU
Display
230VAC/1A
ON FAULT2 FAULT1
HIG93
∻
5 900 kΩ
S1 S2 S3
HAKEL ISOLGUARD
SH B A
230VAC/1A
FAULT2 FAULT1
1 2 3 4 5 6
Picture 1: Terminals designation

ISOLGUARD HIG93, HIG93/L, HIG94 V5.8/23
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When Risol is displayed the status of signalling relay's contacts is indicated by the symbol of contact. In case of fault, the
close contact is displayed.
Terminal TEST
Terminal for connection with the remote test push-button. Remote test push-button is connected between TEST and +12V
terminals.
Terminal +12 V
Terminal for connection with the remote monitoring push-button. See recommended connections of the insulation monitoring
Device.
Terminals A, B, SH
These terminals are intended for connection of galvanic isolated communication line ISOLGUARD RS485. Individual insulation
monitoring devices are connected with twisted pair between A and B conductors. The SH terminal serves for connection of
signal grounds by the interconnecting cable. For description of the communication line see chapter Communication protocol
page 12. This line may be also connected with a remote monitoring module MDS-D with display.
Note:
Terminals +12V and TEST are exclusively intended for connection of the test push-button. These terminals
cannot be used for connection of any other devices.

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Napájení
230 V AC
Systém IT, Uit = max.275V AC
Nadřízený systém
(PC, PLC)
+12V
TEST
A1 A2 PE
HAKEL ISOLGUARD
HIG93/94
CENTRE
SH B A
ON FAULT2 FAULT1
S1 S2 S3
SH
B
A
FAULT2 FAULT1
MENU
1 2 3 4 5 6
L1'
L2'
PE
L
N
TEST
L1'
L2'
PE
ALARM 2
ALARM 1
RS485
ISOLGUARD
PE
Napájení
230 V AC
Systém IT, Uit = max. 3x400V AC
Nadřízený systém
(PC, PLC)
+12V
TEST
A1 A2 PE
HAKEL ISOLGUARD
HIG93/94
CENTRE
SH B A
ON FAULT2 FAULT1
S1 S2 S3
SH
B
A
FAULT2 FAULT1
MENU
1 2 3 4 5 6
PE
L1 L1'
L2'
PE
L2
L3
N
L3'
TL400
L1 L2 L3
CENTRE
Rtl.ext. TEST
ALARM 2
ALARM 1
RS485
ISOLGUARD
PE
4. Recommended connection of HIG93, HIG93/L, HIG94 to the monitored IT power
supply system
Single-phase IT power supply system (maximum 275 V AC), HIG93, HIG93/L, HIG94 modules with alarm signalling
and with the remote test push-button
Picture 2: Connection of HIG93/94 device
in the 1-phase IT power supply system
Three-phase IT power supply system (3x440 V AC), modules HIG93, HIG93/L, HIG94 with alarm signalling and with
the remote test push-button
Picture 3: Connection of HIG93/94 device
in the 3-phase IT power supply

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Menu nastavení Rcrit1
Menu nastavení Rhyst
Menu nastavení Rcrit2
Měřená hodnota
izolačního odporu
Menu nastavení
parametrů
Menu nastavení doby tON
Menu informací Úvodní text
Test zařízení po dobu
držení tlačítka TEST
Bez stisku
tlačítka
5 minut
Zpět na zobrazení Risol
stiskem tlačítka nebo
stiskem ext.testu
Menu nastavení odporu
vnější tlumivky
Menu nastavení doby tTEST
Menu nastavení paměti FAULT
Měřená hodnota se
signalizací blokace
uvolnění
relé FAULT1
a relé FAULT2
odemknutí
kombinace tlačítek
pro odemknutí
symbol zobrazovaný
při zamknutí tlačítek
stav při aktivní
funkci
paměti FAULT
bez
paměti
FAULT
Menu nastavení adresy RS485
Menu nastavení stavu
relé FAULT1/2
Bez zobrazeni
Nastavení zakončovacího
odporu Rte RS485
TEST
MENU
Risol
SEL
sec
+
_
ESC
/SET
+
_
ESC
/SET
ESC
Risol
tON
Rcrit1
TEST
MENU
HIG93/485 5.8
%
+
_
ESC
/SET
Rhyst
kΩ
kΩ
kΩ
_ _ _
58
50
Info
Set Rcrit1
Set Rcrit2
Set Rhyst
Set tON
Set TLext.
Set tTEST
Mem.FAULT
Set 485ADD
Set 485Rte
Set Relay FA
Lock Up
ESC
HIG93/485 5.8
No.: 190000
Rcrit1= 50kΩ
Rhyst1=10kΩ
Rcrit2= 100kΩ
Rhyst2=20kΩ
tON= 0 sec
Rtl.ext.=0.0kΩ
tTEST=0.0 sec
Mem.FAULT:NO
485 ADDR: 1
485 Rte : NO
20
0
HAKEL
Rtl. ext.:
_
+
ESC
/SET
kΩ
00.
tTEST:
_
+
00.
Mem. Fault : NO
+
Risol
DEBLOCK
kΩ
58
Unlock
Risol
kΩ
58
5sec
L
_
ESC
/SET
+
_
ESC
/SET
Rcrit2
kΩ
100
485 ADDR: 1
+
ESC
/SET
_
485 Rte: Yes
_+
ESC
/SET
Relay Logic:
ESC
/SET
N/C = FAULT
ESC
/SET
Picture 4: Displayed information
5. Information on the display
Operating principles
 The meaning of the push-buttons in each menu is shown on the display.
 Pressing the MENU push-button invoke the parameter setting menu.
 Pressing the SEL push-button activates transition to the inversely
displayed parameter settings menu.
 Short pressing the ESC/SET push-button causes exit from the menu
without memorizing the new parameter value.
 Prolonged pressing the ESC/SET push-button causes memorizing
the new parameter value and the menu will end than.
 When no push-button is pressed within 30 seconds, the new value
setting menu will be automatically terminated.
 When no push-button is pressed within 5 minutes, display goes OFF.
 The insulation monitoring device is operational even if there is nothing
shown on the display (display is not active).
 The display is recovered by pressing any of the push-buttons below the display.
 The display is restored by pressing the remote test button if tTEST is set to a value greater than zero.
 After selecting the menu Lock Up the control buttons are locked and the measured value is displayed.
 The unlocking of the device’s control buttons is realized while holding the middle and right button for 5 seconds.
 Releasing the FAULT1 or FAULT2 relay is realized by the middle push-button on the device or by the RS485
ISOLGUARD communication line RS485 order.
 FAULT1 or FAULT2 relay status change, eventually initiation and termination the device test is indicated by a short
display flash.

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5.1 Displayed information HIG93, HIG93/L, HIG94
Opening text
It is displayed for a short time after switching ON the module. The name of the module and software version is displayed. After
the insulation status measuring is started, the measured value of insulation resistance is displayed automatically.
Measured value of insulation resistance
It is displayed in a range as specified in the table of technical characteristics in units of kΩ or MΩ. The value is rounded to
units of kΩ within the adjustable critical insulation resistance range and to tens of kΩ if lying beyond that range.
Pressing TEST push-button activates test of the device, pressing MENU push-button displays parameter settings menu. By
pressing the middle push-button current temperature inside the module is indicated in the upper part of the display. The
signalling relay's status is indicated by the symbol of contact. If both relays are released (there is no fault in the monitored
power supply system) the open contact is displayed. If there is Rcrit1 or Rcrit2 fault signalled, the close contact is displayed.
In a case the non-zero value for the time tON (time until the fault signalling) is set, then when Risol drops below the Rcrit value
the countdown of the time tON starts. The display shows the time until fault signalling. After the time is expired, the fault is
signalled.
Insulation monitoring device test
Test may be performed by pressing push-button on the module, by remote TEST push-button or by the ISOLGUARD RS485
communication line order.
Testing of the insulation monitoring device is performed for 5 seconds or during the time of holding the button. The insulation
resistance value is set lower than Rcrit1 and Rcrit2. Invoked alarm is signalled by indicator lamp FAULT1, FAULT2 and by
FAULT1 and FAULT2 signalling relays’ status according to Set Relay FA parameter. The insulation resistance value is not
shown on the display while testing.
If the push-button on the module is used to initiate the test, then the test starts running immediately.
When using the remote test push-button, the test starts after tTEST parameter delay. When the tTEST value is set greater than
zero the display is recovered immediately after pressing the remote test push-button and test is performed after tTEST parameter
delay.
Remote test via the communication line is performed immediately after receiving the order and takes 5 seconds. If the FAULT
memory is set (Mem.FAULT menu), the signal relay remains in a status of alarm indication even after the test is over, until it
is released by the operator pressing the button on the module. It is also possible to release the relay by an order from the
communication line in the case of remote test via communication line.
The initiation and termination of the device test is indicated by a short display flash.
FAULT memory
This parameter is set in the menu as Mem.FAULT.
If this parameter is set to YES, the FAULT1, FAULT2 relay stays in the fault signalling status even after insulation resistance
fault termination and the word DEBLOCK appears on the display. It is possible to release the relay by pushing device’s middle
button S2. This push-button can be also used when locked device is indicated by the padlock symbol on the display. FAULT1,
FAULT2 relay can be also released by the order from the communication line.
The usage of the FAULT memory including FAULT signalling status after termination is defined by the user.
Parameter settings Menu
Menu to set one of the following values can be selected by using push-buttons arrow up and down
 display of device’s set parameters, menu Info.
 monitored critical resistance, menu Set Rcrit1, Set Rcrit2.
 insulation resistance hysteresis, menu Set Rhyst,
 delay in response of signalling the fault, menu Set tON,
 external inductor resistance, menu Set TLext.,
 delay in start of module test by remote test push-button, menu Set tTEST
 FAULT memory parameter, menu Mem.FAULT
 device addresses on the RS485 bus, menu SET 485ADDR
 terminating resistance Rte of the RS485 bus in the device, menu Set 485Rte
 FAULT1 and FAULT2 relay status when insulation status fault, menu Set Relay FA
 device’s control buttons can be locked, menu Lock Up
For initiating of all menus use the push-button SEL and for exit select ESC.
Information menu
Displays control program version of HIG93, HIG93/L, HIG94 and set operation parameters of the device. Serial number of the
device is also displayed. For exit select the push-button ESC.
Menu set Rcrit1, Rcrit2
New value of the critical insulation resistance is set in kΩ by pressing or holding the + or – push-buttons. The value can be set
in the range of 0,1 kΩ to 90 kΩ for HIG93/L, 5 kΩ to 300 kΩ for HIG93 or in the range of 200 kΩ to 900 kΩ for HIG94. New
value is saved by long holding the ESC/SET, pressing this push-button shortly ends setting procedure and Rcrit value remains
unchanged. Both Rcrit1, Rcrit2 values can be set independently in the whole value range.

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Menu set Rhyst
New value of the critical insulation resistance hysteresis is set in % by pressing or holding the + or - push-buttons. The setting
range of this value is 0 to 100 % Rcrit. New value is saved by long holding the ESC/SET, pressing this push-button shortly
ends setting procedure and the Rhyst value remains unchanged. The hysteresis level in % applies to both of the critical
insulation resistance levels Rcrit1 and Rcrit2.
Menu set tON time
New value of the delay in response of FAULT1 or FAULT2 is set in seconds by pressing or holding the + or – push-buttons.
The value can be set in the range of 0 to 60 sec. New value is saved by long holding the ESC/SET, pressing this button shortly
ends setting procedure and tON value remains unchanged.
Menu set TLext.
External inductor connected in front of the HIG93, HIG93/L, HIG94 device is necessary when monitoring higher voltages, see
recommended connection diagrams. Value of Rtl.ext DC resistance of the connected inductor winding is set in this menu. This
value must be set zero in case of application without the external inductor.
New value of the Rtl.ext resistance is set in kΩ to one decimal place by pressing or holding the + or – push-buttons. The value
can be set in the range of 0 to 20,0 kΩ. New value is saved by long holding the ESC/SET, pressing this button shortly ends
setting procedure and Rtl.ext value remains unchanged.
The value of Rtl.ext inductor’s DC resistance winding is indicated on the inductor’s label as Rin. Typical values for three-phase
HAKEL inductors are as follows: TL400 4,5 kΩ, TL500 4,5 kΩ, TL600 4,5 kΩ, TL1600 12,5 kΩ, TL6003 19,6 kΩ. Exact values
may be obtained by measuring the inductor’s winding resistance with interconnected L outlets at the operational temperature
of the inductor.
Menu set tTEST time
New value of the delay in module test start by pressing remote test push-button is set in seconds by pressing or holding the +
or – push-buttons. The value can be set in the range of 0 to 6 seconds at 0,1 second step. New value is saved by long holding
the ESC/SET, pressing this button shortly ends setting procedure and tTEST value remains unchanged.
When tTEST value setting is greater than 0 the display is re-activated immediately after pressing the remote test button.
Menu Mem.FAULT
Menu for setting the FAULT1/FAULT2 memory. This parameter can be set to YES, when the FAULT1/FAULT2 relay remains
in alarm signalling status even after the fault is eliminated and the button on the device must be pressed to release the relay.
Parameter can be also set to NO without fault memorizing. An order through the RS485 communication line can also release
the relay.
Menu Set Relay FA
FAULT1 and FAULT2 relay status when insulation status fault occurs is set in this menu. This parameter can be set to N/C or
N/O value. The meaning is given in the terminals’ description, page 5.
Menu Lock Up
Menu is intended for locking the device's control push-buttons. When selecting this menu, button combination for unlocking
the module is displayed while holding down the push-button. Measured Risol value and lock symbol are displayed after exiting
the menu. The module is unlocked while holding the middle and right push-button at the same time for more than 5 sec.

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6. Insulation resistance fault evaluation
Evaluation of the FAULT1, FAULT2 according to set tON and Rhyst parameters values is shown in the following figure.
In this example, the set non-zero value for tON and hysteresis Rhyst is shown without setting the FAULT memory parameter.
When the insulation resistance value of the monitored power supply system decreases below Rcrit1 or Rcrit2, the countdown of
the time tON starts. The remaining time is displayed. Once the time tON is expired, the fault is signalized and the FAULT1,
FAULT2 indicator lamp on the device lights up. Particular signalling relay release is cancelled and its contacts are set to the
rest position. The FAULT1, FAULT2 is only terminated when the insulation resistance increases above the value Rcrit1+Rhyst
or Rcrit2+Rhyst. Signalling relay is released and FAULT1, FAULT2 signalling is terminated.
The following left figure shows fault evaluation when insulation monitoring device is set with zero value tON. The following right
figure shows example for setting of insulation monitoring device with the hysteresis zero value Rhyst.
v
Picture 5: Insulation resistance fault evaluation
Picture 6: Insulation status fault evaluation with time tON or hysteresis zero value
Time
Time
No FAULT1
FAULT1
No FAULT2
FAULT2
Time
0
Risol
Rcrit1 Rhyst=0
0tON
Rcrit2 Rhyst=0
tON
0
Time
Time
No FAULT1
No FAULT2
Time
0
Risol
FAULT1
Rcrit1
Rcrit1 + Rhyst
0tON=0
FAULT2
Rcrit2
Rcrit2 + Rhyst
tON=0
0
Time
Time
No FAULT1
Signalling rellay 1 is released Signalling rellay 1 is not released
Signalling rellay 1 is released
No FAULT2
Time
0
Risol
FAULT1
Rcrit1
Rcrit1 + Rhyst
0
tON
FAULT2
Rcrit2
Rcrit2 + Rhyst
tON
0

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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 Rte 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.

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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 kΩ
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 kΩ 1
Critical limit of insulation resistance 2 Rcrit2 100 kΩ 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 kΩ 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

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9. HIG93, HIG93/L, HIG94 parameters factory settings
Device parameters are set to default values during production:
Parameter Menu Symbol Value
HIG93 Value HIG93/L Value HIG94
Critical insulation
resistance 1 Set Rcrit1 Rcrit1 50 kΩ 5 kΩ 300 kΩ
Critical insulation
resistance 2 Set Rcrit2 Rcrit2 100 kΩ 50 kΩ 500 kΩ
Insulation resistance
hysteresis Set Rhyst Rhyst 20 % 20 % 20 %
Delay in response of
signalling the fault Set tON tON 0 sec 0 sec 0 sec
External inductor
resistance Set TLext. Rtl.ext. 0 kΩ 0 kΩ 0 kΩ
Delay in device test start
by remote test button Set tTEST tTEST 0 sec 0 sec 0 sec
FAULT memory Mem.FAULT Mem.FAULT NO NO NO
Module address Set 485ADDR 485 ADDR 1 1 1
Terminating resistance of
the line RS485 Set 485Rte 485 Rte NO NO NO
FAULT1/2 relay status
when fault occurs Set Relay FA Relay FA N/C = FAULT N/C = FAULT N/C = FAULT
Table 6: Factory values of device’s parameters
Note:
1. Parameters meaning of RS485 line is given in communication protocol description.
10. Device dimensions
Picture 9: Device dimensions

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11. Device installation
HIG93, HIG93L, HIG94 are intended for assembling on 35 mm DIN rail according to IEC 60715:2017.
Any working position.
Operation, installation and maintenance can be done only by qualified personnel according to
assembling and safety regulations. If the device is used in the way not specified by the producer,
protection provided by the device could be disrupting.
12. Maintenance and service
It is necessary to follow specified conditions for reliable operation, do not expose the device to rough
handling, keep it clean and ensure maximum admissible temperature of the environment.
Only qualified personnel are allowed to install and set up the device. Only the producer provides repairs of
the device. No personnel are needed to operate the insulation monitoring device. Technology service is during the operation
informed by local and remote monitoring signalization about the monitored power supply and transformer status.
13. Producer
Producer of HIG93/94 insulation monitoring device is
HAKEL spol. s r. o.,
Bratří Štefanů 980, 500 03 Hradec Králové
Czech Republic
www.hakel.com