이름 : Darell Essex
이메일 : darellessex@gmail.com
연락처 :
예식일 : Super Mini-Node Interface Card (SMINI) - Part 1
문의내용:

R1201 sets the PWM frequency used to drive the solenoid. R1202 sets the peak current (Ipeak) used to actuate the solenoid. Ensure that the TVS diode is close to the power connectors to reduce the overall current loop for an outside transient voltage spike. If there's a big voltage spike on the power input due to static discharge or inductive switching, the TVS will shunt it. Since the DC motor is an inductive load this prevents the voltage spike that occurs when the motor is switched off from damaging the MOSFET. The resistor (R201) and diode (D202) protect the MOSFET's gate against transients that may exceed the maximum gate-to-source voltage (VGSS). However, you may find situations where you need to connect the interface to external hardware that is prewired with a common ground and what you need to do is switch the hot, or power side, of the loads. However, being, well, me, I couldn't just leave it as-is! However, to support a distributed system with multiple SMINIs (and/or SUSICs), RS232 will not do the job. It's common to see a beefy Schottky diode used for this purpose, however, that approach becomes problematic with higher current draw because of the diode's power loss.

Make sure power traces and fills are large enough to accommodate the expected current. Make sure each bypass capacitor has strong and short connections to the ground and power planes. Ensure that the bypass capacitors for the 5 V converter and the 3.3 V regulator are as close as possible to their respective pins. Of course, the 3.3 V rail also has an obligatory indicator LED (D205, R204). I've also added an indicator LED for the 5 V rail (D204, R203). Following the Pi filter is a simple indicator LED (D203, R202). The product of the resistor and capacitor values (i.e. R x C), is called the filter time constant. For example, if your requirement does not demand a fast response time for reading inputs, and you desire heavy filtering, I would suggest using the 100Ω resistor with the 10 or 22µF capacitor. For example, Pin 6, Data Set Ready on the DB25, is one that a printer might use to tell the computer it is ready to accept the next character. The RP2040 is pretty flexible in terms of pin assignment for serial I/O, so most of the assignments here were made in order to make the layout easier.

R1001 is a pull-down resistor to make sure the MOSFET is off while the board is powering up. RS485 Bias : 680 Ohm pull-up and pull-down (Jumper selectable). The principal exception is that the RS485 specification is Half-duplex, meaning that it cannot send and receive data simultaneously.ตัว Converter สามารถ Auto Selectable Baud Rate ให้อัตโนมัติ , ด้าน RS485 มีขั้วต่อให้เลือกใช้ได้ทั้งแบบ สกรูขัน(Terminal) หรือ ขั้ว RJ-11, สามารถใช้งานเป็น Converter RS232 to RS422 ได้โดยการสลับ Dip Switch ภายในกล่อง , Converter ตัวนี้ผ่านการทดสอบ การใช้งานภายในโรงงานอุตสาหกรรมมาแล้วเป็นอย่างดี(Industrial Specification).

Compatible with TTL/RS485 standard, converting the TTL signal into a balanced differential RS485 signal, supporting full-duplex communication. In short an application program written to support RS232 comms with no flow control can be made to interface to RS485 without modification. It needs to accurately move the gantry around, control vacuum-powered picking nozzles, and communicate with various digital peripherals such as RGB LEDs and automated feeders. The new control board, named Starfish, has to fulfill a variety of tasks. It's also well suited for this project: there's a lot of digital peripherals to talk to but no analog stuff to deal with which pairs well with the RP2040's abundance of digital I/O and near lack of analog I/O. The only real thing of note on this schematic is the pin assignments for peripherals. The drawback to using literally every I/O pin is that the bypass capacitors are a little further away from the RP2040 than they could be, but, the RP2040 seems more than happy with this layout in practice. It's useful to reference the RP2040 datasheet's pin function table (section 1.4.3) when making those serial connections as there are a few caveats to watch out for. C1402, C1403, and C1404 are bypass capacitors for the various voltage supplies used by the driver.