Q: What is meant by Symmetrical and Asymmetrical breaking currents?

issue:Customer wants to know the value of the symmetrical and asymmetrical breaking current of the circuit breaker and what do they mean.Environment:Circuit Breaker Resolution:- Symmetrical breaking current is the RMS value of AC component of short circuit current at the instant of separation of the contacts. It does not take into account the DC offset.- Asymmetrical breaking current is is the RMS value of the combined sum of the DC and AC components of the short circuit current at the instant of separation of the breaker contacts. This DC offset is of decaying nature which is dictated by the time constant of the system. As shown in the above picture the DC offset decays in a few cycles and is left only with the symmetrical component. Hence if a breaker has to close before the DC component decays, then the breaker’s breaking capacity is to be calculated for the asymmetrical current at the time of breaking.

Q: What is the selection criterion of Circuit Breakers for the Capacitor bank application.

The selection should be done after derating the Circuit Breaker taking into consideration voltage variation and capacitors tolerances that could increase nominal current up to 1.5In. The Derating factor of 1.5In Where In = Q/ ( Square root of 3 ) Un Q = Capacitor Power Un = Nominal Voltage Choose the Micrologic with delay time selection, so that the Circuit Breaker does not trip due to initial high inrush current. Also to be taken into account are the parameters like supply frequency, operating voltage & harmonics level of the power system for such application. Refer the attached sheet for further details for selection of Circuit Breaker for Capacitor duty application. Note: Use the phase barrier between the phases in Circuit Breaker to prevent flashover due to heavy inrush current.

Q: In a 3 phase system, why does the meter still show voltage reading on one of the phases even after breaking the phase circuit?

Issue:Testing phase loss on a meter doesn't result in a null voltage reading.Environmnet:EasyLogic Series Power MetersPowerLogic Series Power MetersResolution:The voltage seen is what we call "phantom voltage", its a known phenomenon with all high impedance power meters. These phantom voltages are normal artifacts of the design and should not pose any safety concerns to the end user.In some cases it'll probably disappear by power cycling the meter. Most power meters are not designed to monitor phase loss, as it'll always assume the presence of the 3 phases and the neutral, depending on your parameters setup. External devices are used to detect such occurrences, like phase control relays.

Q: Which RL(lead resistance from CT to relay) is to be used in Knee Voltage calculation if Current Transformers (CTs) used in High Impedance Restricted Earth Fault are at different distances from relay?

Issue:Having two different values for RL ( Lead resistance from the CT to the relay); RL from the phase CT to the relay and RL from the neutral point CT to the relayEnvironment:Protection Function ANSI 64refHigh impedance differentialSepam 80 Current Transformer requirementResolution:In any application where the high impedance differential is used, all the CTs must have the following:- the same ratio,- the same magnetizing curve (same minimum Vk),- the same maximum Rct (current Transformer secondary winding resistance),- if the relevant CTs are not at the same distance from the relay, take the maximum RL.Attached Cahier Technique no.194 for more information about high impedance calculation

Question 1

What are the G1, G2, G3 and Gx classifications for the ANSI Standard, ANSI/ISA S71.04-1985, “Environmental Conditions for Process Measurement and Control Systems: Airborne Contaminants,”?

Accepted Answer

The G3 specification references the ANSI Standard, ANSI/ISA S71.04-1985, “Environmental Conditions for Process Measurement and Control Systems: Airborne Contaminants,” .The G reference refers to the severity and classification of the test and it can be G1 (Mild, Moderate, Harsh and Severe (G1, G2, G3 and Gx, respectively). The classification directly correlates with the level of corrosive effects in that environment and the standards define or characterise environments in terms of their overall corrosion potential.G1 Mild <300ÅAn environment sufficiently well-controlled such that corrosion is not a factor in determining equipment reliability.G2 Moderate <1000 ÅAn environment in which the effects of corrosion are measurable and corrosion may be a factor in determining equipment reliability.G3 Harsh <2000 ÅAn environment is which there is a high probability that corrosive attack will occur. These harsh levels should prompt further evaluation resulting in environmental controls or specially design and packaged equipment.GX Severe >2000 ÅAn environment in which only specially designed and packaged equipment would be expected to survive. Specifications for equipment in this class are a matter of negotiation between user and supplier.

Question 2

What is the function of BUCHHOLZ relay in oil-filled transformers?

Accepted Answer

Buchholz protection is normally provided on all transformers fitted with a conservator. The Buchholz relay is contained in a cast housing which is connected in the pipe to the conservator, as in figure shown. A typical Buchholz relay will have two sets of contacts. One is arranged to operate for slow accumulations of gas, the other for bulk displacement of oil in the event of a heavy internal fault. An alarm is generated for the former, but the latter is usually direct-wired to the circuit breaker trip relay. The device will therefore give an alarm for the following fault conditions, all of which are of a low order of urgency: a. hot spots on the core due to short circuit of lamination insulation b. core bolt insulation failure c. faulty joints d. interturn faults or other winding faults involving only lower power infeeds e. loss of oil due to leakage When a major winding fault occurs, this causes a surge of oil, which displaces the lower float and thus causes isolation of the transformer. This action will take place for: i. all severe winding faults, either to earth or interphase ii. loss of oil if allowed to continue to a dangerous degree

Question 3

What is Modbus and How does it work?

Accepted Answer

What is Modbus? Modbus is a serial communication protocol developed by Modicon published by Modicon® in 1979 for use with its programmable logic controllers (PLCs). In simple terms, it is a method used for transmitting information over serial lines between electronic devices. The device requesting the information is called the Modbus Client and the devices supplying information are Modbus Servers. In a standard Modbus network, there is one Client and up to 247 Servers, each with a unique Server Address from 1 to 247. The Client can also write information to the Servers.The official Modbus specification can be found at https://modbus.org/ What is it used for? Modbus is an open protocol, meaning that it's free for manufacturers to build into their equipment without having to pay royalties. It has become a standard communications protocol in industry, and is now the most commonly available means of connecting industrial electronic devices. It is used widely by many manufacturers throughout many industries. Modbus is typically used to transmit signals from instrumentation and control devices back to a main controller or data gathering system, for example a system that measures temperature and humidity and communicates the results to a computer. Modbus is often used to connect a supervisory computer with a remote terminal unit (RTU) in supervisory control and data acquisition (SCADA) systems. Versions of the Modbus protocol exist for serial lines (Modbus RTU and Modbus ASCII) and for Ethernet (Modbus TCP). How does it work? Modbus is transmitted over serial lines between devices. The simplest setup would be a single serial cable connecting the serial ports on two devices, a Client and a Server. The data is sent as series of ones and zeroes called bits. Each bit is sent as a voltage. Zeroes are sent as positive voltages and a ones as negative. The bits are sent very quickly. A typical transmission speed is 9600 baud (bits per second). What is hexadecimal? When troubleshooting problems, it can be helpful to see the actual raw data being transmitted. Long strings of ones and zeroes are difficult to read, so the bits are combined and shown in hexadecimal. Each block of 4 bits is represented by one of the sixteen characters from 0 to F. Each block of 8 bits (called a byte) is represented by one of the 256 character pairs from 00 to FF. How is data stored in Standard Modbus? Information is stored in the Server device in four different tables. Two tables store on/off discrete values (coils) and two store numerical values (registers). The coils and registers each have a read-only table and read-write table. Each table has 9999 values. Each coil or contact is 1 bit and assigned a data address between 0000 and 270E. Each register is 1 word = 16 bits = 2 bytes and also has data address between 0000 and 270E. Coil/Register Numbers can be thought of as location names since they do not appear in the actual messages. The Data Addresses are used in the messages. For example, the first Holding Register, number 40001, has the Data Address 0000. The difference between these two values is the offset. Each table has a different offset. 1, 10001, 30001 and 40001. What is the Server ID? Each server in a network is assigned a unique unit address from 1 to 247. When the client requests data, the first byte it sends is the Server address. This way each server knows after the first byte whether or not to ignore the message. What is a function code? The second byte sent by the Client is the Function code. This number tells the server which table to access and whether to read from or write to the table. What is a CRC? CRC stands for Cyclic Redundancy check. It is two bytes added to the end of every modbus message for error detection. Every byte in the message is used to calculate the CRC. The receiving device also calculates the CRC and compares it to the CRC from the sending device. If even one bit in the message is received incorrectly, the CRCs will be different and an error will result. . What are the formats of Modbus commands and responses? What are data types? The example for FC03 shows that register 40108 contains AE41 which converts to the 16 bits 1010 1110 0100 0001 Great! But what does it mean? Well, it could mean a few things. Register 40108 could be defined as any of these 16-bit data types: A 16-bit unsigned integer (a whole number between 0 and 65535) register 40108 contains AE41 = 44,609 (hex to decimal conversion) A 16-bit signed integer (a whole number between -32768 and 32767) AE41 = -20,927 (hex to decimal conversion that wraps, if its over 32767 then subtract 65536) A two character ASCII string (2 typed letters) AE41 = ® A A discrete on/off value (this works the same as 16-bit integers with a value of 0 or 1. The hex data would be 0000 or 0001) Register 40108 could also be combined with40109 to form any of these 32-bit data types: A 32-bit unsigned integer (a number between 0 and 4,294,967,295) 40108,40109 = AE41 5652 = 2,923,517,522 A 32-bit signed integer (a number between -2,147,483,648 and 2,147,483,647) AE41 5652 = -1,371,449,774 A 32-bit double precision IEEE floating point number. This is a mathematical formula that allows any real number (a number with decimal points) to represented by 32 bits with an accuracy of about seven digits. AE41 5652 = -4.395978 E-11 Here is a spreadsheet IEEE float calculator for inputs of 4 bytes or 2 words. To download a copy, right click and select Save Target As... A four character ASCII string (4 typed letters) AE41 5652 = ® A V R More registers can be combined to form longer ASCII strings. Each register being used to store two ASCII characters (two bytes). What is byte and word ordering? The Modbus specification doesn't define exactly how the data is stored in the registers. Therefore, some manufacturers implemented modbus in their equipment to store and transmit the higher byte first followed by the lower byte. (AE before 41). Alternatively, others store and transmit the lower byte first (41 before AE). Similarly, when registers are combined to represent 32-bit data types, Some devices store the higher 16 bits (high word) in the first register and the remaining low word in the second (AE41 before 5652) while others do the opposite (5652 before AE41) It doesn't matter which order the bytes or words are sent in, as long as the receiving device knows which way to expect it. For example, if the number 29,235,175,522 was to be sent as a 32 bit unsigned integer, it could be arranged any of these four ways. AE41 5652 high byte first high word first 5652 AE41 high byte first low word first 41AE 5256 low byte first high word first 5256 41AE low byte first low word first What is a Modbus Map? A modbus map is simply a list for an individual server device that defines - what the data is (eg. pressure or temperature readings) - where the data is stored (which tables and data addresses) - how the data is stored (data types, byte and word ordering) Some devices are built with a fixed map that is defined by the manufacturer. While other devices allow the operator to configure or program a custom map to fit their needs. What is the difference between Modbus ASCII and Modbus RTU? Modbus RTU and Modbus ASCII talk the same protocol. The only difference is that the bytes being transmitted over the wire are presented as binary with RTU and as readable ASCII with Modbus RTU. important to note about RTU is that the RTU message does not have a Start_of_text indication. The receiving party in the communications uses a "silent" time in order to determine the start of a new message. ASCII does have a start-of-text token. Binary messages are shorter than ASCII and therefore theoretically faster to transmit/receive. You may be happy to see update rates of about 100 ms in your HMI/SCADA and could choose either communication.Summary:- use RTU is possible- use ASCII in case RTU is giving timeout problems on WinNT or when using slow communications media like 300 bps or dialup modems Most OPC Servers for Modbus support ASCII as well as RTU communications.. What are extended register addresses? Since the range of the analog output holding registers is 40001 to 49999, it implies that there cannot be more than 9999 registers. Although this is usually enough for most applications, there are cases where more registers would be beneficial. Registers 40001 to 49999 correspond to data addresses 0000 to 270E. If we utilize the remaining data addresses 270F to FFFF, over six times as many registers can be available, 65536 in total. This would correspond to register numbers from 40001 to 105536. Many modbus software drivers (for Client PCs) were written with the 40001 to 49999 limits and cannot access extended registers in server devices. And many server devices do not support maps using the extended registers. But on the other hand, some server devices do support these registers and some Client software can access it, especially if custom software is written. How does 2-byte server addressing work? Since a single byte is normally used to define the server address and each server on a network requires a unique address, the number of server on a network is limited to 256. The limit defined in the modbus specification is even lower at 247. To get beyond this limit, a modification can be made to the protocol to use two bytes for the address. The client and the servers would all be required to support this modification. Two byte addressing extends the limit on the number of servers in a network to 65535. By default, the Simply Modbus software uses 1 byte addressing. When an address greater than 255 is entered, the software automatically switches to 2 byte addressing and stays in this mode for all addresses until the 2 byte addressing is manually turned off. How can you send events and historical data? Enron Modbus includes commands for moving events and historical data.. What is Enron Modbus? Enron Modbus is a modification to the standard Modicon modbus communication protocol developed by Enron Corporation. See Enron Modbus for details.

Question 4

What is the Reason of Earth leakage devices tripping without fault occurrence ?

Accepted Answer

Some types of electrical and electromagnetic interference caused by the network or its environment may affect the operation of earth leakage protection devices and causes their tripping without existence of fault ,which is known by Nuisance tripping (tripping in a non-dangerous situation).This type of tripping is caused by :1-A transient or continuous high-frequency voltage that is superimposed on the normal network voltage (50 Hz).2-High-frequency harmonics3-Low-frequency continuous leakage currents4-Switching capacitive or inductive components5-Common mode voltage surgesType SI RCDs have been designed to avoid nuisance tripping or non-tripping in case of polluted network, lightning effect, high frequency currents, RF waves, etc.

Question 5

What is the Acceptable value of contact resistance for 400V LV Switchboard busbar?

Accepted Answer

Contact resistance can be measured by millivolt drop test and it has to be found by real test. But, it is not a right method to validate any busbar joints. As per IEC 61439 - 1 & 2, temperature rise of a switchboard is important and it is already validated by type test. If the temperature rise is within control, it is really not required to worry about the contact resistance of busbar joints, voltage drops etc. To control the temperature rise, right busbar architecture and device has to be chosen from the derating table provided in the Catalogue / Technical Guide and right torque has to be applied on the connection bolts. If these parameters are ensured as per Okken / Blokset design instruction, the design will be safe.

Question 6

What is meant by vector group for transformers and why is it important?

Accepted Answer

What is vector group for transformers?A vector group is the International Electrotechnical Commission (IEC) method of categorizing the high voltage (HV) windings and low voltage (LV) winding configurations of three-phase transformers.The vector group designation indicates the windings configurations and the difference in phase angle between them.Example: a wye HV winding and delta LV winding with a 30-degree lead is denoted as "Yd11".Common vector group presentations are tabulated below. Why is the vector group important to specify? As different combinations of winding connections will result in different phase angles between the voltages on the windings, transformers connected in parallel must have the same vector group because the mismatching of phase angles will result in circulating current and other system disturbances.

Question 7

What does 1 way, 2 way and intermediate light switching mean?

Accepted Answer

There are 3 basic types of switches that are used for domestic purposes: 1 Way Switches: If a light switch is ‘1 way’ this means it is just an on/off switch. This is the simplest type of switch that you can get. The single switch controls a single light (or lighting circuit).2 Way Switches: A ‘2 way’ switch means there is another switch controlling the same light. These are often used on a stair case, large room with switches by each door.Intermediate Switches: If you need to control the lights from three places, say you have 3 entrances to a large room and need a light switch next to each one, you will need an intermediate switch. The light(s) can be switched on and off from anyone of 3 places. On the whole 2 or 3 gang switches will always be 2 way switches. If you are buying switches and don’t know exactly what you need, then it is often a good idea to get a 2 way switch anyway. This is because if you only need a 1 way switch, you can still use it by only connecting one of the terminals (L1 or L2) and common terminal. (If the switch doesn’t work the way you want it to, you can either turn the switch around or swap the L1 and L2 terminal).

Question 8

Wiring of RS485 Communications Networks

Accepted Answer

IssueThis document attempts to explain correct methods of wiring RS485 communication networks in industrial environments based on various application notes and technical articles. Environment RS485 Serial Modbus Communications Resolution 1. RS-485 (EIA/TIA-485) Differential Data Transmission System Basics The RS-485 standard was developed jointly by two trade associations: the Electronic Industries Association (EIA) and the Telecommunications Industry Association (TIA). The original prefix "RS" stands for Recommended Standard and has been officially replaced with "EIA/TIA" to help identify the origin of its standards. RS-485 Standard SpecificationsMode of operation Differential Allowed no. of Tx and Rx 32 Tx 32 Rx Maximum cable length 4000ft length Maximum data rate 10Mbps Minimum driver output range ±1.5V Maximum driver output range ±5V Minimum drive capability ±55mA Maximum driver short-circuit current 250mA Tx load impedance 54 Rx input sensitivity ±200mV Maximum Rx input resistance 12k Rx input voltage range -7V to +12V Rx logic high >200mV Rx logic low <200mV Max common mode voltage -7V to +12V Full duplex implementation requires 4 wires. This may be necessary for some applications involving legacy devices. In half-duplex implementation 2 wires are used this is the recommended configuration for most Schneider Electric PMC devices.All products manufactured by Schneider Electric PMC support half-duplex, 2 wire configuration. The 4 wire interface is usually implemented in order to avoid creating a T (tee) or star connections or to support full duplex connections.A twisted pair type of cable should be used in order to reduce radiated emissions and improve immunity of the communications system to any external electromagnetic interference. The National Electrical Code and all applicable local regulations must be followed when installing the communications wiring. Cable examples: Belden 9841 or Alpha 6412 or equivalent cable may be used for applications under 300V that are indoors or outdoors in conduit above grade.Belden 3074F or equivalent cable may be used for applications greater than 300V which are indoors or outdoors in conduit above grade. In all devices the RS485 ports are opto-isolated from the internal device electronics. All devices with RS485 port have a shield terminal, which may be connected to the chassis ground (e.g. on 7X50, 880, 8600) or to the isolated reference of the RS485 port (i.e. no connection to the chassis ground as in 6200, 6300, 6100)2. Network Configuration 2.1 TopologySeveral types of network topologies are possible, but the daisy-chain bus configuration is the most efficient. Typically, one of the units is the client controlling the network traffic and prevents multiple drivers from being active at the same time (bus contention). A shielded twisted pair cable is the physical medium. The cable impedance should be within 100-120ohm range. In the Backbone with Studs technology, no studs should be left unconnected at the device end. Otherwise, such a stud will act as an antenna and introduce a significant amount of noise on the RS485 bus, to such a point that communications may become impossible. This is actually a fairly common source of problems. The longer the cable, the lower the data rate: 2.2 TerminationTermination resistors that match the cable's characteristic impedance are essential for minimizing reflections and consequently communication error rates and electromagnetic emissions. For common RS-485 cables (a twisted pair of 24AWG wires), this means a 100-120 resistor at both ends . Termination resistors should be used especially with long cable length to ensure data integrity. Note that, on very long cable length, adding termination resistors can sometime cause an additional drop of voltage that will cause a loss of communication on the devices that are furthest from the client. In this case, adding a repeater or removing some termination resistors can restore communications.2.3 Fails-Safe Biasing Open bus condition:When a node is disconnected from the bus, the state of the bus, as seen by the receiver, is undetermined and may result in random output from the receiver. A weak failsafe biasing is recommended to ensure that the receiver does not enter undetermined state under open bus conditions. Idle bus condition:When no drivers are active on a bus with termination resistors, those resistors will decrease the differential bus voltage to zero, which according to the RS485 standard, is an undefined bus condition. Biasing resistors should be used in order to generate a valid bus logic state under idle-bus conditions. Biasing resistors are only needed at one node (usually the client), hence configuration switches must be used if the biasing resistors are incorporated into every node. Only one device on the bus should be providing the biasing. The biasing resistors may be external or internal to the device. Some products e.g.8800, 7X50 have internal resistors which may be connected with internal switches to provide biasing of the bus. The Com 32 and Com 128 have permanently connected biasing resistors.2.4 Unit Load (U.L.)A one RS485 transceiver represent a load of 1U.L. The RS485 standard specifies the bus loading as 32 U.L. 2.5 Shielding and GroundingThe RS485 interface standard does not specify a ground wire, but such wire is needed to provide a return path for common mode currents and consequently reduce emissions. It may be possible to operate the RS485 loop without a ground wire, but such systems may radiate high levels of EMI. A shield limits coupling of external interference and noise onto the bus. Generally the shield should be connected to the chassis ground (installation ground) at one end of the cable. In case of ground potential differences between nodes (common in industrial locations) this arrangement prevents the flow of DC ground loop currents in the shield. Ground loop currents flowing in the shield will induce noise in the communications cable. A capacitor or an RC network may be used between the other end and ground. The RS485 nodes can tolerate from -7V to +12V of common mode voltage. When this voltage is exceeded the nodes are no longer guaranteed to function and may even be damaged.Due to significant differences in ground potentials that may and will be present between nodes in industrial locations, ground should not be used as a reference. In installations where ground is used as return path 100-120 resistors may be used to limit the ground currents flowing due to ground potential differences between devices. The figure below illustrates the grounding concepts. Connection Example: 6300 meter, terminated daisy chain bus. The shield terminal is not connected to chassis ground of the meter. Installer must ensure low impedance connection to the system ground at one end of the cable. The 4 wire port on the 6300 is intended to help the installer avoid making T (or stub) connections. Note the use of termination resistors RT. Example: third party devices: Examples of improper networks Do NOT do this: Unterminated cable:Incorrect location of termination resistor: Multiple cables in a star configuration Backbone cable with long stubs:

Question 9

What is meant by Symmetrical and Asymmetrical breaking currents?

Accepted Answer

issue:Customer wants to know the value of the symmetrical and asymmetrical breaking current of the circuit breaker and what do they mean.Environment:Circuit Breaker Resolution:- Symmetrical breaking current is the RMS value of AC component of short circuit current at the instant of separation of the contacts. It does not take into account the DC offset.- Asymmetrical breaking current is is the RMS value of the combined sum of the DC and AC components of the short circuit current at the instant of separation of the breaker contacts. This DC offset is of decaying nature which is dictated by the time constant of the system. As shown in the above picture the DC offset decays in a few cycles and is left only with the symmetrical component. Hence if a breaker has to close before the DC component decays, then the breaker’s breaking capacity is to be calculated for the asymmetrical current at the time of breaking.

Question 10

What is the selection criterion of Circuit Breakers for the Capacitor bank application.

Accepted Answer

The selection should be done after derating the Circuit Breaker taking into consideration voltage variation and capacitors tolerances that could increase nominal current up to 1.5In. The Derating factor of 1.5In Where In = Q/ ( Square root of 3 ) Un Q = Capacitor Power Un = Nominal Voltage Choose the Micrologic with delay time selection, so that the Circuit Breaker does not trip due to initial high inrush current. Also to be taken into account are the parameters like supply frequency, operating voltage & harmonics level of the power system for such application. Refer the attached sheet for further details for selection of Circuit Breaker for Capacitor duty application. Note: Use the phase barrier between the phases in Circuit Breaker to prevent flashover due to heavy inrush current.

Question 11

In a 3 phase system, why does the meter still show voltage reading on one of the phases even after breaking the phase circuit?

Accepted Answer

Issue:Testing phase loss on a meter doesn't result in a null voltage reading.Environmnet:EasyLogic Series Power MetersPowerLogic Series Power MetersResolution:The voltage seen is what we call "phantom voltage", its a known phenomenon with all high impedance power meters. These phantom voltages are normal artifacts of the design and should not pose any safety concerns to the end user.In some cases it'll probably disappear by power cycling the meter. Most power meters are not designed to monitor phase loss, as it'll always assume the presence of the 3 phases and the neutral, depending on your parameters setup. External devices are used to detect such occurrences, like phase control relays.

Question 12

Which RL(lead resistance from CT to relay) is to be used in Knee Voltage calculation if Current Transformers (CTs) used in High Impedance Restricted Earth Fault are at different distances from relay?

Accepted Answer

Issue:Having two different values for RL ( Lead resistance from the CT to the relay); RL from the phase CT to the relay and RL from the neutral point CT to the relayEnvironment:Protection Function ANSI 64refHigh impedance differentialSepam 80 Current Transformer requirementResolution:In any application where the high impedance differential is used, all the CTs must have the following:- the same ratio,- the same magnetizing curve (same minimum Vk),- the same maximum Rct (current Transformer secondary winding resistance),- if the relevant CTs are not at the same distance from the relay, take the maximum RL.Attached Cahier Technique no.194 for more information about high impedance calculation

*RS-485 Standard Specifications*
Mode of operation	\n\t\t\t Differential \n\t\t\t
Allowed no. of Tx and Rx	\n\t\t\t 32 Tx 32 Rx \n\t\t\t
Maximum cable length	\n\t\t\t 4000ft length \n\t\t\t
Maximum data rate	\n\t\t\t 10Mbps \n\t\t\t
Minimum driver output range	\n\t\t\t ±1.5V \n\t\t\t
Maximum driver output range	\n\t\t\t ±5V \n\t\t\t
Minimum drive capability	\n\t\t\t ±55mA \n\t\t\t
Maximum driver short-circuit current	\n\t\t\t 250mA \n\t\t\t
Tx load impedance	\n\t\t\t 54 \n\t\t\t
Rx input sensitivity	\n\t\t\t ±200mV \n\t\t\t
Maximum Rx input resistance	\n\t\t\t 12k \n\t\t\t
Rx input voltage range	\n\t\t\t -7V to +12V \n\t\t\t
Rx logic high	\n\t\t\t >200mV \n\t\t\t
Rx logic low	\n\t\t\t <200mV \n\t\t\t
Max common mode voltage	\n\t\t\t -7V to +12V \n\t\t\t

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Schneider Electric Error 404

For Windows 10 or 11 (from Control Expert v16): "SchneiderPLCUsbDriverSuite (v14.16.0.0) Win10 or 11.zip"

Note for X80 Architectures: If a BMXXBE1000 rack extender module is installed at the end of the X80 rack, please ensure the unused port is terminated with the line terminator part number TSXTLYEX.

Section A) Check if the Windows cannot verify the digital signature of the PLC:

Section B) Check if the 'Usb PLC' service is running:

Section C) Check whether or not UsbConnect.exe and UsbConsole.exe are running:

Section D) If these conditions two occur: (Section B-Step 9) "The system cannot find the file specified" and (Section A-Step 5): both UsbConnect.exe andUsbConsole.exe do not exist in the C:\\Windows\\System32\\ folder,
we will need to remove the 'Usb PLC' service from Windows:

Section E) Next, we will uninstall the Schneider Electric 'PLCUsb Driver X64' suite:

Section F) Install the PLCUsb Driver X64 suite.

Section G) Identify and Remove Duplicate Devices in the Device Manager (specifically for M340 only)

Section H) Check for RasClient Error (EventID: 20227) in Windows Event Viewer - Application log folder (specifically for M340)
Specifically for the M340 PLC connection, you may see this combination of symptoms:

Section L: M340 Appears in the Device Manager with COM Port in SE Driver Manager, Yet PLC USB Driver Diagnostic Shows "No (or no active) USB connection"

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Schneider Electric Error 404

For Windows 10 or 11 (from Control Expert v16): &quot;SchneiderPLCUsbDriverSuite (v14.16.0.0) Win10 or 11.zip&quot;

Note for X80 Architectures: If a BMXXBE1000 rack extender module is installed at the end of the X80 rack, please ensure the unused port is terminated with the line terminator part number TSXTLYEX.

Section A) Check if the Windows cannot verify the digital signature of the PLC:

Section B) Check if the &#39;Usb PLC&#39; service is running:

Section C) Check whether or not UsbConnect.exe and UsbConsole.exe are running:

Section D) If these conditions two occur: (Section B-Step 9) &quot;The system cannot find the file specified&quot; and (Section A-Step 5): both UsbConnect.exe andUsbConsole.exe do not exist in the C:\\Windows\\System32\\ folder,we will need to remove the &#39;Usb PLC&#39; service from Windows:

Section E) Next, we will uninstall the Schneider Electric &#39;PLCUsb Driver X64&#39; suite:

Section F) Install the PLCUsb Driver X64 suite.

Section G) Identify and Remove Duplicate Devices in the Device Manager (specifically for M340 only)

Section H) Check for RasClient Error (EventID: 20227) in Windows Event Viewer - Application log folder (specifically for M340)Specifically for the M340 PLC connection, you may see this combination of symptoms:

Section L: M340 Appears in the Device Manager with COM Port in SE Driver Manager, Yet PLC USB Driver Diagnostic Shows &quot;No (or no active) USB connection&quot;

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For Windows 10 or 11 (from Control Expert v16): "SchneiderPLCUsbDriverSuite (v14.16.0.0) Win10 or 11.zip"

Section B) Check if the 'Usb PLC' service is running:

Section D) If these conditions two occur: (Section B-Step 9) "The system cannot find the file specified" and (Section A-Step 5): both UsbConnect.exe andUsbConsole.exe do not exist in the C:\\Windows\\System32\\ folder,
we will need to remove the 'Usb PLC' service from Windows:

Section E) Next, we will uninstall the Schneider Electric 'PLCUsb Driver X64' suite:

Section H) Check for RasClient Error (EventID: 20227) in Windows Event Viewer - Application log folder (specifically for M340)
Specifically for the M340 PLC connection, you may see this combination of symptoms:

Section L: M340 Appears in the Device Manager with COM Port in SE Driver Manager, Yet PLC USB Driver Diagnostic Shows "No (or no active) USB connection"