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What's are the differences between and SV203 (sometimes called SV203A) SV203B and SV203C boards?

The SV203 (Sometimes called the SV203A) does not have a standalone programing mode, this allows for a larger (80 character) recieve buffer. It also has a smaller EEPROM becuase the space is not needed to store the application program.

The SV203B and SV203C are really both SV203B PCB's, the SV203C is just packaged with an IR100 board.

If I buy an IR100 board at a later time for my SV203B will I get SV203C functionality?


Can I use and IR100 board with my SV203?


I can't communicate with my SV203, what in the world could be wrong?

  1. Make you are sending all uppercase (capital) letters to the SV203, it is case sensitive
  2. You must be using a straight through serial cable, pins 2→2, 3→3, 5→5 minimum required connections
  3. Port settings: 9600bps, 8 bits, No Parity, 1 Stop Bit, Flow control: None (9600,8N1,XOFF)
  4. Make sure you are using the correct port
    • Loop back the signal by shorting pins 2 & 3 to see if the character transmitted is received

What power supplies would you recommend for your board?

Servo motors require very little power when they are not moving or under load. However, once moving or under load, especially moving with a load, the smallest servos can require an amp or more of current. As the servo's size or load increases so will the power required to run the servo.

The moment a motor first starts moving, it will cause a momentary power rush that can cause many wall type power supplies to not effectively deliver the required power to the circuit 1). If this happens, the voltage output from your power supply will drop. If the voltage drops significantly, the microcontroller on the SV203 PCB will go into reset. Common symptoms of a poor power supply will manifest as “Gittering Servo Motors while unable to Communicate” or “Servo Motors recentering after a Move Command”. Both of these symptoms can usually be cured by either using a power supply with a slightly higher voltage output(7DCV) or by using a supply with a higher current output. TechTip: A large capacitor in parallel with a weak power supply can help improve its performance.

When running more than a couple of servos this problem may be very apparent. Many PONTECH customers have found that the best way to prevent this problem is by using two separate power supplies, one for logic power and one for motor power. When using two supplies, if the voltage or current drops because of increased load to the servo this may slow the servo down, but will not stop it from running as long as there is adequate logic power for the SV203.

This can be done by cutting the trace between the two pins on the bottom side of the board of JP1 2) (to the right of the DB9 connector with the PONTECH logo right reading). When this is done the servos can be powered either through an unused servo connector or by populating the PWR2 connector of the board directly above the JP1 position.

When I have the IR100 plugged in can I still used the A/D or SPI port?

Yes, you can use both!

1) There are two primary control schemes for power supplies, constant voltage and constant current with constant voltage being the most common control scheme used. In constant voltage mode a voltage is set and the current is allowed to fluctuate to maintain the output voltage as the load (or power requirements) of the connected circuit change. The converse is true with a constant current power supply. In either case there is a maximum power that can be delivered by the power supply. If a circuit connected to the supply requires more power than can be delivered by supply weather in constant current or constant voltage mode, the control is lost and one of two things will happen, no addition current will be delivered or the voltage will drop lowering the power requirements for the connected load.
2) When I cut a trace on a PCB I use an exact-o knife. I just score the trace in two places between the two pin holes of the JP1 connector and peal it off. The copper metal of the trace is pretty thin and attached to the PCB substrate (FR4) using a light adhesive. The purpose of the JP1 connector is to be able to restore the common power between servos and the logic if at some future time you would like to undo cutting the trace. This can be done by installing a two pin header and using a jumper at this position.
products/sv203.txt · Last modified: 2015/06/08 15:11 by jacob