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MAEN015A, 2011-05
iX Panel T4A
Installation Manual
English
Foreword
Installation manual for iX Panel T4A
Foreword
All iX Panels are developed to satisfy the demands of human-machine communication. Built-in functions such as displaying and controlling text, dynamic indication, time channels, alarm and recipe handling are included.
The operator panel works primarily in an object-oriented way, making it easy to understand and use. Configuration is carried out on a PC using the iX Developer configuration tool. The project can then be transferred and stored in the operator panel itself.
Various types of automation equipment such PLCs, servos or drives can be connected to the iX Panels. In this manual, the term “the controller” refers to the connected equipment.
This manual explains how to install the operator panel. Please refer to the iX
Developer reference manual for further information.
Order no: MAEN015A
Copyright © 2011-05 Beijer Electronics AB. All rights reserved.
The information in this document is subject to change without notice and is provided as available at the time of printing. Beijer Electronics AB reserves the right to change any information without updating this publication. Beijer Electronics AB assumes no responsibility for any errors that may appear in this document.
Read the entire installation manual prior to installing and using this equipment. Only qualified personnel may install, operate or repair this equipment. Beijer Electronics AB is not responsible for modified, altered or renovated equipment. Because the equipment has a wide range of applications, users must acquire the appropriate knowledge to use the equipment properly in their specific applications. Persons responsible for the application and the equipment must themselves ensure that each application is in compliance with all relevant requirements, standards and legislation in respect to configuration and safety. Only parts and accessories manufactured according to specifications set by Beijer Electronics AB may be used.
BEIJER ELECTRONICS AB SHALL NOT BE LIABLE TO ANYONE
FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR
CONSEQUENTIAL DAMAGES RESULTING FROM THE
INSTALLATION, USE OR REPAIR OF THIS EQUIPMENT, WHETHER
ARISING IN TORT, CONTRACT, OR OTHERWISE. BUYER'S SOLE
REMEDY SHALL BE THE REPAIR, REPLACEMENT, OR REFUND
OF PURCHASE PRICE, AND THE CHOICE OF THE APPLICABLE
REMEDY SHALL BE AT THE SOLE DISCRETION OF BEIJER
ELECTRONICS AB .
Beijer Electronics, MAEN015A
Contents
Contents
1 Safety Precautions ....................................................... 4
1.1
General ........................................................... 4
1.2
During Installation .............................................. 4
1.3
During Use ....................................................... 5
1.4
Service and Maintenance ........................................ 5
1.5
Dismantling and Scrapping ..................................... 5
2 Installation ............................................................... 6
2.1
Space Requirements ............................................. 6
2.2
Installation Process .............................................. 7
2.2.1
Connections to the Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2.2
Other Connections and Peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3 Technical Data ........................................................... 10
4 Chemical Resistance .................................................... 12
4.1
Metal Casing ..................................................... 12
4.2
Touch Screen and Overlay ....................................... 13
4.2.1
Autotex F157/207 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
4.2.2
Touch Screen Surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
4.2.3
Autoflex EB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
5 Operator Panel Drawings .............................................. 15
5.1
Communication Ports ........................................... 15
5.2
iX Panel T4A Outline ............................................ 16
6 Additional Installation Tips ............................................ 17
6.1
Grounding the Operator Panel ................................. 17
6.2
Ethernet Connection in the Panel .............................. 18
6.3
To Achieve Better EMC Protection ............................. 19
6.4
Ambient Temperature ........................................... 20
6.5
Safety ............................................................. 21
6.6
Galvanic Isolation ................................................ 22
6.7
Cable and Bus Termination RS485 ............................. 23
Beijer Electronics, MAEN015A
Safety Precautions
1 Safety Precautions
Both the installer and the owner and/or operator of the operator panel must read and understand this installation manual.
1.1 General
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Read the safety precautions carefully.
Check the delivery for transportation damage. If damage is found, notify the supplier as soon as possible.
Do not use the operator panel in an environment with high explosive hazards.
The supplier is not responsible for modified, altered or reconstructed equipment.
Use only parts and accessories manufactured according to specifications of the supplier.
Read the installation and operating instructions carefully before installing, using or repairing the operator panel.
Never allow fluids, metal filings or wiring debris to enter any openings in the operator panel. This may cause fire or electrical shock.
Only qualified personnel may operate the operator panel.
Storing the operator panel where the temperature is lower/higher than recommended in this manual can cause the LCD display liquid to congeal/become isotopic.
The LCD display liquid contains a powerful irritant. In case of skin contact, wash immediately with plenty of water. In case of eye contact, hold the eye open, flush with plenty of water and get medical attention.
The figures in this manual serves an illustrative purpose. Because of the many variables associated with any particular installation, the supplier cannot assume responsibility for actual use based on the figures.
The supplier neither guarantees that the operator panel is suitable for your particular application, nor assumes responsibility for your product design, installation or operation.
1.2 During Installation
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–
–
–
–
The operator panel is designed for stationary installation on a plane surface, where the following conditions are fulfilled: no high explosive risks no strong magnetic fields no direct sunlight no large, sudden temperature changes
Install the product according to the accompanying installation instructions.
Ground the product according to the accompanying installation instructions.
Only qualified personnel may install the operator panel.
Separate the high voltage, signal and supply cables.
Make sure that the voltage and polarity of the power source is correct before connecting the product to the power outlet.
Peripheral equipment must be appropriate for the application and location.
Beijer Electronics, MAEN015A 4
Safety Precautions
1.3 During Use
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•
Keep the operator panel clean.
Emergency stop and other safety functions may not be controlled from the operator panel.
Do not use too much force or sharp objects when touching the keys, touch screen etc.
1.4 Service and Maintenance
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Only qualified personnel should carry out repairs.
The agreed warranty applies.
Before carrying out any cleaning or maintenance operations, disconnect the equipment from the electrical supply.
Clean the display and surrounding front cover with a soft cloth and mild detergent.
Replacing the battery incorrectly may result in explosion. Only use batteries recommended by the supplier.
1.5 Dismantling and Scrapping
•
•
The operator panel or parts thereof shall be recycled according to local regulations.
The following components contain substances that might be hazardous to health and the environment: lithium battery, electrolytic capacitor and display.
Beijer Electronics, MAEN015A 5
Installation
2 Installation
2.1 Space Requirements
•
•
Maximum installation plate thickness: 11 mm
Space requirements when installing the operator panel:
100 mm
104 mm 50 mm 50 mm
100 mm
43 mm
145 mm
Caution:
The openings on the enclosure are for air convection. Do not cover these openings.
100 mm
Beijer Electronics, MAEN015A 6
2.2 Installation Process
1. Unpack and check the delivery. If damage is found, notify the supplier.
Note:
Place the operator panel on a stable surface during installation.
Dropping it or letting it fall may cause damage.
2. Use the cut out dimensions that are included on the outline drawing to cut a correct opening in the cabinet. A separate cut out drawing is available for download from the Beijer Electronics web site.
3. Secure the operator panel in position, using all the fastening holes and the provided brackets and screws:
Installation x 4
0.5 - 1.0
Nm
Beijer Electronics, MAEN015A 7
Installation
4. Connect the cables in the specified order, according to the drawing and steps below.
Caution:
• Ensure that the operator panel and the controller system have the same electrical grounding (reference voltage level), otherwise errors in communication may occur.
• The operator panel must be brought to ambient temperature before it is started up. If condensation forms, ensure that the operator panel is dry before connecting it to the power outlet.
• Ensure that the voltage and polarity of the power source is correct.
• Use only shielded communication cables.
• Separate high voltage cables from signal and supply cables.
B
RS232/
RS422/
RS485
24V DC
C
D
A
Power
Controller
24V DC
Ethernet
–
–
–
–
Connect cable A.
Connect cable B, using an M5 screw and a grounding conductor (as short as possible) with a cross-section of minimum 2.5 mm 2 .
Connect cable C.
Connect cable D.
5. Carefully remove the laminated film over the operator panel display, to avoid static electricity that could damage the panel.
Note:
When connecting the operator panel to the power outlet for the first time, make sure not to interrupt power for a minimum of 48 hours in order to charge the battery completely. After that, the battery may be charged partly during a shorter period of time.
Beijer Electronics, MAEN015A 8
Installation
2.2.1
Connections to the Controller
For information about the cables to be used when connecting the operator panel to the controller, please refer to the help file for the driver in question.
2.2.2
Other Connections and Peripherals
Cables, peripheral equipment and accessories must be suitable for the application and its environment. For further details or recommendations, please refer to the supplier.
Beijer Electronics, MAEN015A 9
Technical Data
3 Technical Data
Parameter
Front panel, W x H x D 145 x 103 x 7 mm
Weight
Serial port for COM1
RS232 and COM2
RS422/RS485
Serial port for COM3
RS232 and COM4
RS422/RS485
Ethernet
USB
Processor
1 x 10 Base-T / 100 Base-T (shielded RJ 45)
1 x USB Host 2.0, max output current 500 mA
400 MHz ARM9
1 x SD card (optional) iX Panel T4A
Mounting depth 43 mm (143 mm including clearance)
Standalone mounting VESA 50x50
Note: Maximum screw length for VESA mounting is 4 mm.
Usage of longer screws may lead to damage.
Front panel seal
Rear panel seal
Touch screen material
Touch screen operations
Reverse side material
Frame material
IP 65
IP 20
Polyester on glass, resistive.
Overlay: Autotex F157 or F207*.
1 million finger touch operations
Powder-coated aluminum
Powder-coated aluminum
0.5 kg
9-pin D-sub contact with RS232 RTS/CTS, chassis-mounted female with standard locking screws 4-40 UNC
9-pin D-sub contact with RS422 RTS, chassis-mounted female with standard locking screws 4-40 UNC
External storage media
Flash memory
Memory RAM
LED
Real time clock
Power consumption at rated voltage
Fuse
Power supply
Display
128 MB SSD (Nand Flash)
64 MB (DDR2)
1 x blue
Yes (on chip)
Normal: 150 mA
Internal DC fuse, 2.0 AT, 5 x 20 mm
+24 V DC (16 – 36 V DC), max. 2 A.
CE: The power supply must conform with the requirements according to IEC 60950 and IEC 61558-2-4.
UL and cUL: The power supply must conform with the requirements for class II power supplies.
TFT-LCD. 480 x 272 pixels, 16.7 million colors (true color).
LED backlight
95.0 x 53.9 mm Active area of display, W x H
Operating temperature
-10 ° to +60 ° C
Beijer Electronics, MAEN015A 10
Parameter iX Panel T4A
Storage temperature -20 ° to +85 °C (depending on display)
Relative humidity
Approvals and certifications
<95 % non-condensed
Information is available on the web site www.beijerelectronics.com
* See section Chemical Resistance for more information.
Technical Data
Beijer Electronics, MAEN015A 11
Chemical Resistance
4 Chemical Resistance
4.1 Metal Casing
The frame and casing material is powder-coated aluminum. This powder paint withstands exposure to the following chemicals without visible change:
Acetic acid 10%
Citric acid 10%
Diesel
Distilled water
Edible oil
Fuel oil
Hydrogen peroxide 3%
Phosphoric acid 4%
Phosphoric acid 10%
Sea water
Sodium chloride 2%
Sodium chloride 20%
Sulphuric acid 20%
Tap water
The powder paint shows limited resistance to the following chemicals at room temperature:
Butanol
Hydrochloric acid 5%
Isopropyl alcohol
Na-hypochlorite 10%
Nitric acid 3%
Nitric acid 10%
Phosphoric acid 43%
Turpentine
Note:
If exposure to any of the above chemicals is demanded, it is recommended to first test the chemical on an “invisible” spot of the metal casing.
The powder paint shows little or no resistance to the following chemicals at room temperature:
Acetic acid, conc.
Acetone
Ammonia 5%
Ammonia, conc.
Ethyl acetate
Methyl-ethyl ketone
Nitric acid 30%
Phenol
Sodium hydroxide 5%
Sodium hydroxide 30%
Toluene
Trichlorethylene
Xylene
97 octan unleaded petrol
98 octan leaded petrol
Beijer Electronics, MAEN015A 12
Chemical Resistance
4.2 Touch Screen and Overlay
4.2.1
Autotex F157/207
Autotex F157 or F207 covers the overlay surrounding the touch screen.
Solvent Resistance
Autotex F157/F207 withstands exposure of more than 24 hours duration under
DIN 42 115 Part 2 to the following chemicals without visible change:
Acetonitrile
Ajax / Vim in solution
Alkalicarbonate solution 1
Diesel Downey / Lenor
Ethanol
1 Phosphoric acid (<30%)
Potassium ferricyanide
Ammonia (<40%) 1
Acetic acid (<50%)
Ariel powder in solution 1
Bleach 1
Castor oil
Glycerine
Hydrochloric acid (<36%)
Linseed oil
Methanol
Potassium hydroxide
(<30%)
Pure Turpentine Glycol
Gumption 1 SBP 60/95 1
Sulfuric acid (<10%)
Tomato ketchup
Trichloroacetic acid
(<50%)
Caustic soda (<40%) 1
Cutting oil
Nitric acid (<10%)
Paraffin oil
White Spirit
Windex 1
Cyclohexanol
Diacetone alcohol
Persil powder in solution 1 Wisk
Petroleum spirit 1
1 Extremely faint glossing of the texture was noted.
-
Autotex withstands DIN 42 115 Part 2 exposure of up to 1 hour duration to glacial acetic acid without visible change.
Autotex is not resistant to high pressure steam at over 100 °C or the following chemicals:
Concentrated mineral acids
Concentrated caustic solution
Benzyl alcohol
Methylene chloride
Beijer Electronics, MAEN015A 13
Chemical Resistance
4.2.2
Touch Screen Surface
The touch screen surface on the panel withstands exposure to the following solvents without visible change:
Solvents Time
Acetone
Isopropanol
Toluene
4.2.3
10 minutes
10 minutes
5 hours
Autoflex EB
It is recommended to use the Autoflex EB touch display protection film, that can be ordered from Beijer Electronics.
Solvent Resistance
Autoflex EB withstands exposure to the same chemicals as Autotex F157 or F207 according to section Autotex F157/207 .
Outdoor Use
In common with all polyester based films Autotex EB is not suitable for use in conditions of long term exposure to direct sunlight.
Beijer Electronics, MAEN015A 14
Operator Panel Drawings
5 Operator Panel Drawings
5.1 Communication Ports
7
8
9
2
3
4
5
6
1
Pin
Serial port, 9-pin female
COM1 COM2
RS422 TX+ /
RS485 TX+/RX+
RS232 RX
RS232 TX
GND
RS422 RX+
GND
RS422 TX- /
RS485 TX-/RX-
RS232 RTS
RS232 CTS
RS422 RX-
Serial port, 9-pin female
COM3 COM4
RS422 TX+ /
RS485 TX+/RX+
RS232 RX
RS232 TX
GND
RS422 RX+
GND
RS422 TX- /
RS485 TX-/RX-
RS422 RTS+
RS422 RTS-
RS422 RX-
Beijer Electronics, MAEN015A 15
5.2 iX Panel T4A Outline
Operator Panel Drawings
104 max 11 mm material thickness
7
43
SD memory card slot
USB host
9 87 9
Beijer Electronics, MAEN015A 16
Additional Installation Tips
6 Additional Installation Tips
When experiencing communication problems in for example noisy environments or when operating close to temperature limits, the following recommendations are to be noticed.
6.1 Grounding the Operator Panel
Mounting plate in the cabinet Door
Operator panel
3
2
Power supply
1
24 V DC
Ferrite core
6
5
4
5350
The operator panel’s mounting clamps do not provide a secure grounding connection between the panel and the device cabinet, see 1 in drawing above.
1. Connect a 2.5 mm 2 wire between the operator panel’s quick-connect plinth and the panel chassis, see 2 in drawing above.
2. Connect a 6 or 4 mm 2 wire or grounding braid between the panel’s chassis and the closest grounding point on the door, see 3 in drawing above.
3. Connect a strong but short grounding braid between the door and the device cabinet, see 4 in drawing above.
4. Twist the cables onto the 24 V DC feed, see 5 in drawing above.
2 turns around the ferrite core provide 4 times the suppression of 1 turn.
3 turns around the ferrite core provide 9 times the suppression of 1 turn.
A ferrite core suppresses disturbances to the 24 V feed, see 6 in drawing above.
Note:
The grounding wires should be short and the conductor should have a large area.
A long, thin grounding wire has a very high impedance (resistance) at high frequencies and will not guide disturbances to the ground.
Multi-wire conductors are better than single wire conductors with the same area.
A braided conductor wire with the same area is even better. The best is a short, thick grounding braid.
Beijer Electronics, MAEN015A 17
Additional Installation Tips
6.2 Ethernet Connection in the Panel
Industrial Ethernet
RJ45
RJ45
1
RJ45
RJ45
3
Operator panel
RJ45 2
Operator panel
RJ45
Shielded
4
1-1
2-2
3-3
8-8
5
Short and unshielded
Operator panel
RJ45
Operator panel
RJ45
0.1 uF
250 V
5351
In some industrial units for Ethernet, the RJ45 contact’s shield is connected to the chassis via a capacitor, see 1 in drawing above.
The operator panel’s Ethernet shield is directly connected to the chassis, see 2 in drawing above.
1. Check whether the other Ethernet unit has its shield directly grounded or grounded via a capacitor.
Note:
In many cases, connecting the shielded Ethernet cabling to the chassis at both ends is inappropriate. Hum or grounding loops can occur. Unshielded cabling may even result in fewer communication errors.
A good solution may be to use a shielded Ethernet cable, but to connect the shield at one end only.
One option is to break the shield, see 3 in drawing above.
A more elegant method is to expand the shielded Ethernet cabling with a piece of unshielded Ethernet cable, see 4 in drawing above.
You can ground the shield via an external 0.1 uF/250 V plastic capacitor, see 5 in drawing above. This will connect the HF transients to the ground.
Beijer Electronics, MAEN015A 18
Additional Installation Tips
6.3 To Achieve Better EMC Protection
•
•
•
•
•
•
•
•
Initially, use the original cabling from Beijer Electronics primarily.
Use shielded cables for RS232 communication.
Use twisted pair and shielded cabling for RS422 and RS485.
Use the cabling intended for the bus type; Ethernet, Profibus, CC-Link,
CAN, Device Net etc.
Install and connect according to applicable specifications for the relevant bus standard.
Use shielded cabling for Ethernet, preferably with foil + braided shield.
D-sub covers should be shielded, and the shield should be connected to the cover 360 ° where the cable comes in.
Connect the shield at both ends.
Shielded cable
Ground plane 1
0.1 uF/250 V
Ground plane 2
Not same potential
Ground plate
5352
Ground plate in another building
With longer distances, there is a risk that the ground potential may be different.
In that case, the shield should only be connected at one end. A good alternative is to connect the other end of the shield to the ground via a 0.1 uF/250 V plastic capacitor. Both ends are then connected to the ground in terms of HF, but only connected to the ground at one end in terms of LF, thus avoiding the 50 Hz grounding loops.
Metal cabinet
Terminal or connector
Metal cabinet
Terminal or connector
EMC cable gland
Shielded cable
Cable clamp in steel
Plastic cable gland
Shielded cable 5353
1. Use an EMC cable gland or regular plastic cable gland, remove the outer jacket and connect the shield to the installation plate with a 360 ° metal cable clamp.
2. Place the 24 V DC and communications cabling in one cable trunk/cable duct and 230/380 V AC in another. If the cables need to be crossed, cross them at
90 ° only. Avoid combining the cabling for stronger 24 V DC outputs with the communication cabling.
Ferrite cores that are snapped onto the shielded cabling may remove minor disturbances. Large ferrite pieces that are snapped onto unshielded cabling and where the wires go 2-4 times around the cores are approximately 5-25 times more efficient.
Beijer Electronics, MAEN015A 19
Additional Installation Tips
6.4 Ambient Temperature
The maximum ambient temperature for the operator panel is provided in the specifications. The ambient temperature refers to the temperature in the device cabinet which cools the panel’s electronics.
Operator panel
Top
50 °C inside
Power
30 °C outside Middle
45 °C inside
Power
Power
Axial fan
120 x 120 mm
Airflow
Bottom
40 °C inside
5354
In most cases, the ambient temperature for the operator panel is significantly higher than the device cabinet’s ambient temperature.
If the cabinet is tall and there are a number of heat-generating devices, the temperature at the top of the cabinet will be considerably higher than the theoretical temperature increase that would be expected. All electronics are sensitive to heat. The lifespan of an electrolytic capacitor is cut in half with an 8-10
° increase in temperature. A 15-20 ° temperature increase results in a quarter of the lifespan etc.
Rittal has a good program for estimating the anticipated average temperature in the cabinet as well as a large program for controlling the temperature in the device cabinet.
An enamel-coated steel cabinet has a radiant heat value of 5.5 W/m 2
C.
and degrees
Installing a fan inside the cabinet will even out the temperature, while moving air provides considerably better cooling than still air. A suitable fan is a 120 x 120 mm axial fan, available in 24 V DC, 115 and 230 V AC.
Install the fan so that it sits in the cooler area and will blow cold air against the operator panel. If the fan is mounted at the top and sucks air upwards, the fan’s ambient temperature will be higher = shorter lifespan.
A good fan with a ball-bearing mounting has an expected lifespan of at least
40,000 hours (not a guaranteed lifespan) at 40 °C. This corresponds to at least 4 years of continuous use. If a thermostat is installed, the fan only needs to come on when needed.
Large graphic terminals draw only one fifth of the current when the background lighting is off. The loss effect drops from e.g. 25 W to only 5 W.
The operator panel’s loss effect = supply voltage x current. Virtually no power goes to external users and no loss effects due to inputs.
Beijer Electronics, MAEN015A 20
Additional Installation Tips
6.5 Safety
Most of the operator panels are fed with 24 V DC.
Power supply
230 V AC to 24 V DC
1
+24 V
0 V
Operator panel
Power supply
230 V AC to 24 V DC
4
Operator panel
2
+24 V
0 V
4
Distance?
3
Power supply
230 V AC to 24 V DC
4
+24 V
0 V
230 V AC
Operator panel
COM1
Small controller with expansion unit
Ch0
Ch1
COM100 Ch100
Ch101
5355
If you use a power supply that meets safety standards and only feeds the operator panel, there is no problem. See 1 in drawing above.
However, if you have a 24 V unit that also feeds other units, there is reason to be cautious, see 2 in drawing above. The operator panel does not have insulation that meets safety requirements in the event of a potential short circuit between 230 V
AC and 24 V DC. It is assumed that the 24 V feed is secure, for example, SELV according to EN 60950 (protection against electric shock) and UL 950.
Example:
Here is an example that explains why a secure 24 V DC feed can be ruined by mixing 24
V relay contacts with 230 V AC relay contacts in a smaller controller. Check that the
“clearances and creepage distances between 24 V DC and 230 V AC fulfill EN 60950 or UL
950”. If not, input a separate 24 V unit into the operator panel.
•
•
•
If there is a substantial distance between the relay contacts for 24 V DC and 230 V
AC, it is OK to use the same 24 V devices for all feeds. See 3 in drawing above.
Connect 0 V on the 24 V feed to the ground, see 4 in drawing above. This offers three advantages:
Safety is increased. The 24 V feed will not be live in the event of a faulty connection or short circuit between 0 V (24 V) and 230 V phase.
Transients on the 24 V feed are connected to the ground.
No risk that the 24 V feed is at a high level in relationship to the ground. This is not unusual since there is high static electricity.
Beijer Electronics, MAEN015A 21
Additional Installation Tips
6.6 Galvanic Isolation
Internal electronic
+24 V DC
0 V
Filter
DC/DC galvanic isolation
1.5 m
VCC
0 V (GND)
RS422/485 RS232 USB USB
Ethernet
DC/AC
CFL
5356
The operator panel has galvanic isolation against the 24 V DC feed but no galvanic isolation between the communication ports for RS232, RS422/485 and USB.
Only the Ethernet connection has galvanic isolation.
Printer
*
PC
*
Operator panel
RS422
*
RS232
*
USB
*
Not same ground potential
Modular controller
Power CPU COM COM2
* * *
* = Internal 0 V (GND) connection
PC
*
5357
When a PC is connected to the panel, the panel’s internal 0 V (GND) will be connected to the protective ground via the PC.
A number of USB devices can have the shield connected together with the protective ground. Here, the panel’s 0 V (GND) is connected to the protective ground when, for example, a USB memory stick, keyboard or similar device is plugged in.
If a number of units are connected that have a 0 V and a ground connection, and these are connected to various grounding points, there is a substantial risk of problems. Grounding currents go through communication cables, the rear plate of the controller, and internally in the operator panel, and can cause errors.
Use external units to improve communication and achieve galvanic isolation.
Westermo has good industry-standard insulators that are also insulated from the
24 V DC feed.
Note:
It is very important to make sure that the 24 V feed in the external insulation unit is not connected to one of the communication outlets. If it does not have 100% insulation against the 24 V feed, disturbances and grounding currents from the 0 V on the 24 V side will disrupt communication.
Using this type of unit solves one problem but creates a larger problem! A substandard installation may work now, but problems may arise when other devices are connected.
Beijer Electronics, MAEN015A 22
Additional Installation Tips
6.7 Cable and Bus Termination RS485
•
•
•
Use shielded and twisted pair cable. The pair capacitance may not exceed 52.5
pF/m and area at least 0.25 mm 2 (AWG 24), if you want to use the maximum transfer distance and maximum transfer speed.
0 V, the reference voltage for communication should be included in the cabling. With two-way communication use two pairs; one pair for communication and one pair for 0 V.
The shield must be grounded at one end. The other end is usually grounded, but with longer distances or when there is a difference in the ground potential, the shield should be connected to the ground via 0.1 uF/250 V plastic capacitor to prevent ground current in the braided shield. A number of manufacturers recommend that the shield be grounded at each node. Various manufacturers have different systems for bus termination. The RS485 standard does not describe how the “Fail Safe” function would be carried out, just that the system should be able to handle the error.
Depending on the recipients’ design, the bus wires may be on the same level or require pull-up or pull-down to ensure that no faulty signals are detected when the bus is in resting mode (all transmitters are disconnected).
+5 V
0 V
1 K
120 ohm
1 K
1
120 ohm
2 3
Inside operator panel
+5 V 14
2
15
6
19
(120 ohm)
7
8
1 K
1 K
0 V
0 V
4
17
CAB8
50
Operator panel
RS422
2
15
3
16
17
4
+5 V
14
0 V
0 V
8
7
VCC
CAB8
VCC
1 K
120 ohm
1 K
Bus
RS485
5
6
3
4
7
1
2
8
Shield
0 V
0 V
Bus termination
5358
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Some (older) operator panels had pull-up and pull-down resistance except for the actual bus termination at 120 ohm, similar to Westermo and Profibus. See 1 in drawing above.
Newer panels have another type of recipient, so-called built-in “Fail Safe”, where simple bus termination resistance is sufficient. See 2 in drawing above.
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If other nodes on the RS485 network require pull-up and pull-down and the operator panel is at one end of the loop, one of the following procedures can be carried out:
Connect two 1k/0.25 W resistors in the 25-pole D-sub contact. See 3 in drawing above. Set jumper pins 6-19.
Use CAB8. It offers the option of bus termination with pull-up/-down. It is also easy to connect the bus cable via the screw terminal block. See 4 in drawing above.
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Head office
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201 24 Malmö, Sweden www.beijerelectronics.com / +46 40 358600
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