EtherNet/IP is open-source and is managed and developed by the Open DeviceNet Vendors Association (ODVA), a tax-exempt business league that includes a wide variety of…
What is Modbus?
Modbus, initially developed in 1979, is one of the oldest, most widely used industrial communications protocols. Traditionally, Modbus was/is implemented using RS-232, RS-422, or RS-485…
SeaMAC: ssiEncodingNone vs ssiEncodingNrz
Is the 7203e PCIe serial interface dip switch or software configurable to change the RS-485 termination from a 120 Ohm resistor to an AC termination?
Sealevel’s 7203e does have onboard dip switches that would allow you to turn off the 102 Ohm resistor; the 120 Ohm resistor can be changed through dip…
Parity, Checksum, and Cyclic Redundancy Check (CRC)
Parity is actually an extra bit that’s added to every data word. It can detect a one bit error within that data or byte Checksum…
Raw Mode or Bit-Shift Mode
Raw mode is actually the simplest form of communication. The card takes every bit of data that’s received from the communication line, groups it into…
Synchronous Data Link Control (SDLC) Vs. High-Level Data Link Control (HDLC)
High-Level Data Link Control (HDLC) takes Synchronous Data Link Control (SDLC) one step further. HDLC defines the content of the control byte, allowing the transmitter…
Synchronous Data Link Control (SDLC)
Synchronous Data Link Control, also known as SDLC, is a protocol that can be used for talking between computers or between computer and a remote…
Bisynchronous communications
Bisynchronous communications have a 16-bit synchronization sequence at the beginning of the message. The rest of the message is formatted using characters like start of…