Characteristics of CAN bus

Characteristics of CAN
The CAN protocol has the following characteristics.
(1) Multi-master control When the bus is idle, all units can start sending messages (multi-master control).
The unit that first accesses the bus can obtain the transmission right (CSMA / CA method * 1).
When multiple units start sending at the same time, the unit that sends the high-priority ID message can obtain the right to send.
(2) Sending messages In the CAN protocol, all messages are sent in a fixed format. When the bus is idle, all units connected to the bus can start sending new messages. When two or more units start sending messages at the same time, the priority is determined according to the identifier (IdenTIfier is referred to as ID below). The ID does not indicate the destination address of the transmission, but indicates the priority of the message accessing the bus. When two or more units start sending messages at the same time, each bit of each message ID is arbitrated and compared. The unit that wins arbitration (it is judged to have the highest priority) can continue to send messages, and the unit that loses arbitration immediately stops sending and performs the receiving work.
(3) The flexibility of the system The unit connected to the bus has no information similar to "address". Therefore, when adding units on the bus, the hardware, software and application layers of other units connected to the bus do not need to be changed.
(4) The communication speed can be set according to the scale of the entire network.
In the same network, all units must be set to a uniform communication speed. Even if the communication speed of one unit is different from the others, this unit will output an error signal, which hinders the communication of the entire network. Different networks can have different communication speeds.
(5) Remote data request can request other units to send data by sending "remote control frame".
(6) Error detection function, error notification function, error recovery function All units can detect errors (error detection function).
The unit that detects the error will immediately notify all other units at the same time (error notification function).
Once the unit that is sending a message detects an error, it will force the current transmission to end. The unit that forcibly ends the transmission will retransmit this message repeatedly until it is successfully transmitted (error recovery function).
(7) Fault closure
CAN can determine whether the type of error is a temporary data error on the bus (such as external noise, etc.) or a continuous data error (such as internal unit failure, driver failure, disconnection, etc.). With this function, when a continuous data error occurs on the bus, the unit that caused the fault can be isolated from the bus.
(8) Connect
The CAN bus is a bus that can connect multiple units at the same time. The total number of connectable units is theoretically unlimited. However, the number of units that can be connected is actually limited by the time delay on the bus and the electrical load. Decreasing the communication speed increases the number of connectable units; increasing the communication speed decreases the number of connectable units.
【Note】 * 1 CSMA / CA: Carrier Sense MulTIple Access / Collision Avoidance

Product Description

SPD Surge Protective Device,Lightning Surge Protector
Surge Protection Device (SPD)
 
It is a device used to limiting instant surge voltage and discharge surge current, it at least including a non-linear component.
 
Surge protective Device Model Selection
 
With the impact of international information flow, the rapid development of microelectronic science and technology, communication, computer and automatic control technology, make the building start to go for high quality, high functional area, formed a new building style-intelligent building. As inside the intelligent building there are lot of information system, <<Building lightning protection design norm>> GB50057-94(2002 vision)(hereafter brief as <<lightning protection norm>>) put forward the relative requirement to install the surge protective device, to ensure the information system safely and stable running.
SPD essentially is a equipotential connection material, its model selection is according to the different lightning protection area, different lightning electromagnetic pulse critical and different equipotential connection position, decide which kind of SPD used in the area, to achieve the equipotential connection with the common earth electrode. Our statement will based on SPD's maximum discharge current Imax, continuous operating voltage Uc, protection voltage Up, alarm mode etc.
As per << Lightning Protection Norm>> item 6.4.4 stipulation "SPD must can withstand the expected lightning current flow and should confirm to the additional two requirements: the maximum clamp voltage during surge across, capable to extinguish the power frequency follow-on current after lightning current across."  That is the value of SPD's max. clamp voltage add its induction voltage of two ends should be same with the system's basic insulation level and the equipment allowed max. surge voltage. 
 
SPD for Power Supply System Series Selection Guide
 
The installation of SPD at each lightning protection zone, according to the standard of Low Voltage Electrical appearance, make classification of electrical equipment in accordance with the over voltage category, its insulation withstand impulse voltage level can determine the selection of SPD. According to the standard of low voltage electrical appearance, make classification of electrical equipment in accordance with the over voltage category as signal level, loading level, distribution and control level, power supply level. Its insulation withstand impulse voltage level are:1500V,2500V,4000V,6000V. As per to the protected equipment installation position different and the different lightning current of different lightning protection zone, to determine the installation position of SPD for power supply and the break-over capacity.
The installation distance between each level SPD should not more than 10m, the distance between SPD and protected equipment should as short as possible, not more than 10m. If due to limitation of installation position, can't guarantee the installation distance, then need to install decoupling component between each level SPD, make the after class SPD can be protected by the prior class SPD. In the low voltage power supply system, connecting an inductor can achieve the decoupling purpose. 
SPD for power supply system specification selection principle 
Max. continuous operating voltage: bigger than protected equipment, the system's max. continuous operating voltage. 
TT System: Uc≥1.55Uo (Uo is low voltage system to null line voltage)
TN System: Uc≥1.15Uo
IT System: Uc≥1.15Uo(Uo is low voltage system to line voltage)
Voltage Protection Level: less than the insulation withstand impulse voltage of protected equipment
Rated discharge current: determined as per to the lightning situation of the position installed and lightning protection zone.
SP1 Series
 
Normal Working Conditions
-Altitude not exceed 2000m
-Ambient air temperature:
Normal range: -5ºC~+40ºC
Extend range: -40ºC~+80ºC
-Relative Humidity: 30% - 90% under indoor temperature condition
- At the place without obviously shaking and shock vibration
- Non-explosion danger medium, non-corrosion gas and dust ( including conductive dust) 
 
Classification
 
-As per Nominal Discharge Current: 
5,10,20,30,40,60KA(8/20µs)
- As per Maximum continuous operating voltage: 
275V,320V,385V,420V,440V,460V
- As per to poles
1P,1P+N,2P,3P,3P+N,4P
- As per auxiliary functions:
a. With remote signal output ( remote alarm function)
b. Without remote signal output
 
Selection Principle
 
- The continuous applied voltage on the two terminals of SPD should not more than the maximum continuous operating voltage Uc value;
- The voltage protection level Up of SPD should less than the maximum impulse withstand voltage of the protected equipment;
- As per to the different earthing system and protection mode to select the specification accordingly;

Product Features

1, built-in over-current overheating, temperature control circuit technology.

2, the module design, easy installation, online replacement.

3, low leakage current, fast response time, low residual voltage.

4, alarm indication device, green (normal) v red (fault).

Model/Technical Parameters	WR-B60	WR-B80	WR-B100	WR-B120	WR-B150
Rated Operating Voltage Un (V ~)	220V 380V	220V 380V	220V 380V	220V 380V	220V 380V
Maximum Continuous Operating Voltage Uc (V ~) kV	385V 420V	385V 420V	385V 420V	385V 420V	385V 420V
Voltage Protection Level Up (V ~) kV	≤1.8≤2.2	≤2.4≤2.5	≤2.5≤3.2	≤3.4≤3.7	≤4.0≤4.5
Maximum Discharge Current Imax(8/μ20μs)kA	60	80	100	120	150
Nominal Discharge  Current In(8/μ20μs)kA	30	40	60	80	100
Response Time	<25			<100
L/N(mm²)The Cross Section Of L/N Line	16,25	16,25	16,25	16,25	25,35
PE (mm²)The Cross Section Of PE Line	16,25	25,35	25,35	25,35	35
Fuse or Switch (A)	63A	63A	63A,100A	63A,100A	63A,125A
The Line Section of Communication and Alarm (mm²)	≥ 1.5
Operating Environment-C	(-40ºC~-+85ºC)
Relative humidity 25 ºC	≤95%
installation	Standard Rail35mm
Material of Outer Covering	Fiber Glass Reinforced Plastic

Surge Protection Device SPD

Surge Protector SPD,Surge Protection Device SPD

Wenzhou Korlen Electric Appliances Co., Ltd. , https://www.korlenelectric.com