Acrel AIM-T500 User manual

200
AIM-T500 Insulation Monitoring Device
Installation and Operation Manual V1.4
Acrel Co., Ltd.

Declaration
Please read this instruction carefully before using this product. All pictures, logos and
symbols involved are owned by Acrel Co., Ltd. All or part of the content shall not be
reproduced publicly without written authorization by non-company personnel.
Please read the instructions and precautions in this operation manual carefully before
using this series of products. Acrel will not be responsible for personal injury or economic
loss caused by ignoring the instructions in this operation manual.
The equipment is professional electrical equipment, any related operation, need to be
carried out by special electrical technicians. Acrel is not responsible for personal injury or
financial loss resulting from the error of non-professional personnel.
The contents of this description will be updated and amended constantly, and it is
inevitable that there will be a slight discrepancy between the physical product and the
description in the product function upgrading. Please refer to the physical product purchased
and obtain the latest version of the description through www. acrel.cn or sales channels.

Modified Records
No.
Time
Versions
Reasons for revision
1
2018.06.18
V1.0
First version
2
2019.01.15
V1.1
Modify error
3
2020.03.28
V1.2
Add overview content; Simplified model description;
Modify the opening size; Modify wiring terminal; Modify
the inaccurate part of the communication address table.
4
2020.07.03
V1.3
Modify the model description; Modify the typical wiring
diagram, modify the terminal, and modify the instrument
auxiliary power supply section description.
5
2022.02.30
V1.4
Modify the format, add modify records; Model description
Do not specify the model; Modify technical parameters.
Notes:

Contents
1 Introduction.......................................................................................................................... 1
2 Functional characteristics..................................................................................................... 1
3 Type Introduction................................................................................................................. 1
4 Technical parameters............................................................................................................ 2
5 Reference standards ............................................................................................................. 2
6 Installation and connection .................................................................................................. 2
6.1 Shape and size................................................................................................................ 2
6.2 Method of installation .................................................................................................... 3
6.3 Wiring method................................................................................................................ 3
6.4 Matters need attention.................................................................................................... 4
7 Program and Usage .............................................................................................................. 4
7.1 Panel............................................................................................................................... 4
7.2 LED instructions............................................................................................................. 5
7.3 Function description of keys .......................................................................................... 5
7.4 Operation instructions of keys........................................................................................ 5
8 Communication Instruction.................................................................................................. 7
8.1 Modbus-RTU communication protocol ......................................................................... 7
8.2 Introduction to the function code ................................................................................... 7
8.3 Address table of AIM-T500........................................................................................... 9
9 Typical applications ........................................................................................................... 10

1 / 11
AIM-T500 Insulation Monitoring Device
1 Introduction
AIM-T500 insulation monitoring device is designed and developed by Acrel gathering the design
experience of electric power meter industry for many years to monitor the insulation condition of low
voltage IT distribution system (ungrounded system). The product adopts advanced micro controller
technology, with high degree of integration, compact size and easy installation, and it integrates
intelligence, digitalization and networking. The device, with many functions such as insulation fault
warning, fault alarm, event recording and so on, can be used in the mines, glass factories, electric
furnaces and test facilities, metallurgical plants, chemical plants, and exploded dangerous places,
computer center, emergency power supply and other places to monitor the insulation status of IT system
in real time. When insulation fault occurs, it will alarm and remind the staff to check the fault.
The products conform to the requirements of enterprise standard Q/VDCL-26-2017 IT System
Insulation Monitor.
2 Functional characteristics
2.1 Function of insulation resistance monitoring, warning and alarm for the monitored IT system.
2.2 Multiple fault indication function, such as relay alarm output and LED alarm output.
2.3 Advanced field bus communication technology, and it can communicate with the host computer
management terminal and monitor the operation status of the IT system in real time.
2.4 Fault event recording function. It can record the time and type of failure to provide convenience for
operators to analyze the operation status of the system and eliminate faults in time.
2.5 Applicable for insulation monitoring of AC, DC and AC / DC hybrid IT systems.
2.6 Self checking function. realize the fault self-inspection of instrument hardware circuit.
2.7 Broken line monitoring function. Monitor the connection condition of the PE/KE.
2.8 The free option of manual reset/automatic reset.
2.9 Wide range of measurement, Allowable leakage capacitance of the system is large.
3 Type Introduction
AIM
Design Number
Type of Product
Application
T500
Instructions: AIM for Acrel Insulation monitoring device;
T for Industrial;
500 for 500 type.

2 / 11
4 Technical parameters
Item
Parameter
Accessory power supply
AC 85~265V; DC100~300V; 50/60Hz
Power dissipation
< 8W
System voltage
AC 0~690V; DC 0~800V; 40~460Hz
System application
IT system (online), Other system (offline)
Insulation
monitoring
Measuring range
1k~10MΩ
Alarm range
10k~10MΩ
Resistance accuracy
1~10k,1k; 10k~10M, ±10%
system leakage capacitance
<500μF
Response time (Ce=1μF)
<5s
Internal
parameters
Measuring voltage
<50V
Measuring current
<270μA
Internal DC impedance
≥180kΩ
Relay output
Error, Alarm, Warning
SOE
20 records (fault type, fault value, fault time)
Alarm type
LCD, LED indicator
Communication
RS485, Modbus-RTU
Impulse voltage / Pollution Level
8kV/Ⅲ
EMC/ Radiation
IEC61326-2-4
Environment
Working temperature
-10 ~+65℃
Storage temperature
-20~+70℃
Relative humidity
<95%, without condensation
Altitude
≤2500m
5 Reference standards
■ IEC 61557-8 Electrical safety in low voltage distribution systems up to 1000V a.c. and 1500V d.c. -
Equipment for testing, measuring or monitoring of protective measures - Part 8: Insulation monitoring
devices for IT systems
■ IEC 61326-2-4 Electrical equipment for measurement, control and laboratory use - EMC
requirements - Part 2-4: Particular requirements - Test configurations, operational conditions and
performance criteria for insulation monitoring devices according to IEC 61557-8 and for equipment
for insulation fault location according to IEC 61557-9
6 Installation and connection
6.1 Shape and size
AIM-T500 externality and installation size (unit: mm)

3 / 11
AcrelAcrelAcrelAcrelAcrelAcrel
ON
ERROR
WARNING
ALARM
COMM
TEST/ESC MENU/
AIM-T500
Front view vertical view
The above diagram is the rear view, side view and front view of the AIM-T500 insulation
monitoring device of the embedded installation in succession.
6.2 Method of installation
The AIM-T500 insulation monitor adopts embedded installation, and the above diagram is the hole
dimensional drawing of the insulation monitor.
6.3 Wiring method
Upper terminals: T1, T2 (31, 32) are self-check terminals. They can judge whether the measurement
of the resistance of the instrument is accurate. This function must be used without access to the DC
system. Short connection with T1 and T2 will display instrument measurement results. F1, F2 (23, 24)
are interconnected terminals, when two ungrounded systems are interconnected. The instruments that
have access to F1 and F2 will stop working, and it will be monitored separately by another instrument.
AK (9) is an extension terminal, used for insulation monitoring of IT systems above AC690/DC800V,
see ACPD series manual for details. L1, L2 (4, 5) are connected to the monitored IT system (No three-
phase neutral phase IT system can be connected to any 2 phase; When a three-phase IT system with
neutral lines is connected, both L1 and L2 are connected to the neutral line; When the single-phase DC
system is connected, the L1 is connected to the positive stage and the L2 is connected to the negative
pole).
31
T1
32
T2
23
F1 F2
24 9
AK
5
L2
4
L1
Lower terminal: KE, PE (28, 29) are instrument functional grounding lines. They need to be
separately connected to the field equipotential grounding terminal. The terminals of U1 and U2 (1, 2)

4 / 11
are instrument auxiliary power interfaces. A, B (18, 19) terminals are RS485 communication A and B
line interface respectively. They are used to communicate with the host computer. DO1+ and DO1-
(12, 13), DO2+ and DO2- (14, 15), DO3+ and DO3- (16, 17) are 3 sets of relay outputs. They
successively correspond to error alarm, fault alarm, and fault warning.
121314151617
PEKE
2829
B
1918
A
1
U1
2
U2
6.4 Matters need attention
6.4.1 Embedded installation of insulation monitor can be installed in a distribution cabinet.
6.4.2 When wiring is installed, connection should be made in connection with the wiring diagram. It is
best to connect the wiring with the needle sleeve connector before inserting the corresponding terminal
of the instrument and tighten the screws to avoid improper operation of instruments due to poor
contact.
6.4.3 The device provides asynchronous half duplex RS485 communication interface, adopts Modbus-
RTU protocol, and all kinds of data information can be transmitted on communication lines. In theory,
up to 128 devices can be connected to one line at the same time. Each device can set its address and
baud rate through the menu. It is recommended to use shielded twisted pair when communicating with
the upper computer system. The cross section of each core should not be less than 0.5mm2, and they
connect to A, B respectively. When shielding layer is connected to earth, wiring should be kept away
from strong cable or another strong electric field. It is recommended that a matched resistance in
parallel should be added between the A and B terminals of the most terminal insulation monitoring
device, and the recommended resistance is 120Ω .
6.4.4 The relay output, without power alarm , is a passive output, so an extra power supply is required
for the alarm(or caution light).
7 Program and Usage
7.1 Panel
Each part of the AIM-T500 panel is shown below.
LCD
LED
Key
LED
Type
AcrelAcrelAcrelAcrelAcrelAcrel
AIM-T500
ON
ERROR
WARNING
ALARM
COMM
TEST/ESC MENU/

5 / 11
7.2 LED instructions
5 LED indicators are used to indicate the status of the insulation monitor:
"ON": when the device is working normally, the indicator light flickers, and the scintillation
frequency is about once a second.
"COMM": when the device has communication data to receive or send, the indicator light flickers.
"ERROR": when the device PE, KE breaks, the indicator light flickers.
"WARNING": When the insulation resistance of the monitoring is less than the warning value, the
warning indicator light flickers.
"ALARM": when the insulation resistance of the monitoring is less than the alarm value, the alarm
indicator light flickers.
7.3 Function description of keys
There are four buttons in the device. They are Self-checking /Backspace, Up key, Down key,
Menu / Enter respectively.
7.4 Operation instructions of keys
7.4.1 Key operation under the main interface
(1) When starting up, enter the main interface by default. If there is no other key operation, the
system will go into the main interface and work. The insulation resistance value, the leakage
capacitance value and the current system time are showed on the main interface.
Press up and
down key
Press ESC to return
Press up and
down key
ESC return
--------------------
SOE Record
--------------------
NO.01:alarm R= 4K
time:15-07-01 11:30
flip
2015-07-02 12:30:45
--------------------
+ IT-SYSTEM
--------------------
Insu. Rf > 10 MΩ
Leakage Ce = 000 uF
ESC return
--------------------
SOE Record
--------------------
NO.02:alarm R= 10K
time:15-07-01 11:28
flip
(2) Check the alarm record. In the main interface, one can enter the event record query interface
by pressing the "Up" or "Down" to turn the page to successively query the most recent 20 fault
records. The first one is the latest record, and the twentieth record is the oldest one.
(3) Self-examination of the instrument. When press the "TEST" button, the monitor will start the
Key
Key function
TEST / ESC
In the non-programming mode, it is used to start the self-checking;
In programming mode, it is used to exit.
Up key,
Down key
In the non-programming mode, it is used to read the alarm record;
In programming mode, it is used to increase or decrease the figure.
MENU/
In non-programming mode, press button to enter programming mode;
In programming mode, they are used as Backspace confirmation or selection
key.

6 / 11
self-examination program to simulate insulation faults and system errors. The 5 LED lights are on at
the same time, and the relay is closed. The self-check results will be displayed after 2S or so to check
whether the alarm and other functions of the instrument is normal.
7.4.2 Parameter setting
(1) Enter the menu
Under normal operation, enter the password input page by pressing the key. Set the size of number
by "Up" and "Down", press "" to enter the menu after inputting the correct password. Otherwise, the
password error will be displayed and automatically returned after 1s.
(2) LCD Settings
After entering the menu, select "LCD Settings" and press "Up" and "Down" to adjust the LCD
contrast (long press is supported). You can adjust the LCD backlight time. After the modification is
complete, press the "Back" key to exit. At this time, you can choose whether to save the setting and
press Enter to confirm and exit.
(3) Security Settings
Enter the menu and select "Security Settings". Press "Up" and "Down" to adjust the warning and
alarm values (long press is supported). Press The Back key to exit. At this time, you can choose
whether to save the settings. Press Enter to confirm and exit. (The default alarm value is 38K and the
early warning value is 60K)
(4) Communication Settings
After entering the menu, select Communication Settings and press Up or Down to adjust system
communication parameters (hold down is supported). Press The Back key to exit. At this time, you can
choose whether to save the settings. Press Enter to confirm and exit. (The default communication
address is 1 and baud rate is 9600).
(5) Setting of other information
The insulation monitor also provides the functions of Clearing Records, Password Setting, Software
Information, and Capacitor Setting. The settings of these parameters are similar to those described in
the preceding steps.

7 / 11
AlarmSet Comm Set
ClearSOE Password
LCD Set Time Set
--------------------
--------------------
Save Set？
Yes No
--------------------
Enter Password:
0000
--------------------
SW info. Cap Set
adjust
--------------------
LCD Set
--------------------
Contrast : 30
Time Hold: 060s
select
--------------------
Time Set
--------------------
Data Set:2015-07-02
Time Set: 13:18:29
--------------------
Alarm Set
--------------------
Warning: 0060K
Alarm : 0030K
--------------------
Comm Set
--------------------
Address : 001
Baud rate: 9600
--------------------
Password
--------------------
Input New Password:
0000
--------------------
Language
--------------------
Chn Eng
Press MENU Press Up and Down to input password
Press Enter to confirm
Press ESC to return
Press Up and Down to select Yes or No
Press Enter to confirm
Press Up and Down to set LCDSet, press
ESC to save or exit
Press Enter to confirm
Press Up and Down to
select the TimeSet and
press Enter to confirm.
adjust select
adjust select
adjust select
adjust select
adjust select
Press Up and Down to
select the AlarmSet and
press Enter to confirm.
Press Up and Down to set TimeSet, press
ESC to save or exit
Press Up and Down to set AlarmSet, press
ESC to save or exit
Press Up and Down to
select the CommSet and
press Enter to confirm.
Press Up and Down to
select the Password and
press Enter to confirm.
Press Up and Down to
select the Language and
press Enter to confirm.
Press Up and Down to set CommSet, press
ESC to save or exit
Press Up and Down to set Password, press
ESC to save or exit
Press Up and Down to set Language, press
ESC to save or exit
2015-07-02 12:30:45
--------------------
+ IT-SYSTEM
--------------------
Insu. Rf > 10 MΩ
Leakage Ce = 000 uF
Select Language:
8 Communication Instruction
8.1 Modbus-RTU communication protocol
Meter RS485 interface adopts Modbus-RTU communication protocol, which defines the address,
function code, data, check code in detail. It is the necessary content to complete the data exchange
between the host and slave machine.
8.2 Introduction to the function code
8.2.1 Function code 03H or 04H: Read the registers
This function allows to acquire the data by equipment and the system parameters. The number of

8 / 11
data requested by hosts has no limit, but cannot exceed the defined address range.
The following example shows how to read a measured insulation resistance value from No.01 slave
computer, with the address of the value of 0008H.
The host computer sends
Send
message
The slave computer
returns
Return
message
Address code
01H
Address code
01H
Function code
03H
Function code
03H
Start address
High byte
00H
Bytes
02H
Low byte
08H
Register
data
High byte
00H
Number of
registers
High byte
00H
Low byte
50H
Low byte
01H
CRC check
code
Low byte
B8H
CRC check
code
Low byte
05H
High byte
78H
High byte
C8H
8.2.2 Function code 10H: Write the registers
The function code 10H allows the user to change the contents of multiple registers, which can write
the time and date in this meter. The host can write up to 16 (32 bytes) data at a time.
The following example shows a preset address of 01 with an installation date and time of 12:00,
Friday, December 1, 2009.
The host computer sends
Send
message
The slave computer
returns
Return
message
Address code
01H
Address code
01H
Function code
10H
Function code
10H
Start address
High byte
00H
Start address
High byte
00H
Low byte
04H
Low byte
04H
Number of
registers
High byte
00H
Number of
registers
High byte
00H
Low byte
03H
Low byte
03H
Number of registers
06H
CRC check
code
Low byte
C1H
0004H data
High byte
09H
High byte
C9H
Low byte
0CH
0005H data
High byte
01H
Low byte
05H
0006H data
High byte
0CH
Low byte
00H
CRC check
code
Low byte
A3H
High byte
30H
Note: The above data is for reference only, see address table for register definition

9 / 11
8.3 Address table of AIM-T500
No.
Address
Parameter
Read/
write
Value range
Data
Type
1
0000H
Passwords
R
0000-9999 (default 0000)
word
2
0001H high
Address
R
1~247 (default 1)
word
0001H low
Baud rate
R
0~3: 4800, 9600, 19200, 38400
(unit bps) (default 9600)
3
0002H high
Contrast ratio
R
15-60 (default: 30)
word
0002H low
Display time
R
15~250 (unit second) (default 60, 15 light)
4
0003H high
Year
R/W
0~99
word
0003H low
Month
R/W
1~12
5
0004H high
Day
R/W
0~31
word
0004H low
Warning mark
R
0: none 1: warning 2: early warning and alarm
6
0005H high
Hour
R/W
0~23
word
0005H low
Minute
R/W
0~59
7
0006H high
Second
R/W
0~59
word
0006H low
Data stable
R
0 or 1 (0 invalid, 1 stable)
8
0007H high
Warning value
R/W
60~4999 (unit: k Ω) (default: 60)
word
0007H low
Warning value
9
0008H high
Alarm value
R/W
10~4999 (unit: k Ω) (default: 38)
word
0008H low
Alarm value
10
0009H high
Resistance value
R
1~10001 (unit: k Ω)
word
0009H low
Resistance value
11
000AH
SN (high 16 bits)
R
Default: 0000000000
word
12
000BH
SN (low 16 bits)
word
13
000CH
Reserve
word
14
000DH
Leakage capacity
R
0~500 (unit: μF)
word
15
000EH high
Symbol of broken
line
R
0: none
4:PE/KE broken line
word
000EH low
Current period
2~200 (unit s)
16
000FH high
Whether access
system
R
0: no access system
1: access system
word
000FH low
Reserve
17
0010H high
Fault
Record
1
STA1
R
The sequence number of incident record
word
0010H low
R
Incident1content: 0~2
0: a fault free record
1: early warning
2: alarm
18
0011H
resistance
value
R
incident 1 insulation resistance
word
19
0012H high
Year1
R
incident 1 time -year
word
0012H low
Month1
R
incident 1 time -month

10 / 11
9 Typical applications
Typical connection diagram
20
0013H high
Day1
R
incident 1 time -day
word
0013H low
Hour1
R
incident 1 time -hour
21
0014H high
Minute1
R
incident 1 time -minute
word
0014H low
Second1
R
incident 1 time -second
22~1
16
0015H-
0073H
The remaining 19 events are recorded in this part of the space, and the rules and
formats are the same as the first.

11 / 11
N
U
V W
PE
Connect three phase load
AC220V powersupply
?three-phase isolated transformer
N line cannot be grounded
AIM-T500 insulation monitor is applied to the connection
diagram of 3-phase IT system
Note: 1 The source power of meter is AC220V
L1
L2
PE
AIM-T500 insulation monitor is applied to the connection
diagram of single-phase IT system
Explain:Alarm relay output control external alarm indicator (if necessary)
Among them, D01+, D01- control the error indicating lamps, D02+, D02-
control alarm indicating lamp.
D03+ and D03- control the warning indicating lamp. The malfunction fault indicates that the meter itself is out of order.
Generatrix?interconnection
external self-check
If the N line is not elicited, access any 2 phase in the 3
RS485 communication can be netted with other
tables and connected to the upper computer
?single-phase isolated transformer
Generatrix?interconnection
external self-check
Connect single phase load
AC220V powersupply
RS485 communication can be netted with other
tables and connected to the upper computer
2 In DC System L1 link to + L2 link to -
121314151617
PEKE
2829
B
1918
A
1
U1
2
U2
31 32 23
F2 24 5
L2
4
L1
T1 T2 F1 AK
9
121314151617
PEKE
2829
B
1918
A
1
U1
2
U2
31 32 23
F2 24 5
L2
4
L1
T1 T2 F1 AK
9

Headquarters: Acrel Co., LTD.
Address: No.253 Yulv Road Jiading District, Shanghai，China
TEL.: [phone] 0086-21-69156052 0086-21-59156392 0086-21-69156971
Fax: [phone]
Web-site: www.acrel-electric.com
mail: [email protected]
Postcode: 201801
Manufacturer: Jiangsu Acrel Electrical Manufacturing Co., LTD.
Address: No.5 Dongmeng Road,Dongmeng industrial Park, Nanzha Street,Jiangyin City,Jiangsu
Province,China
TEL：[phone]
Fax：[phone]
Web-site: www.jsacrel.com
Postcode: 214405
E-mail: [email protected]