Array 3311 RS-232C to TTL Adapter for Array 364X/371X

Product Code: 3311

Overview Image Placeholder — Array 3311 RS-232C to TTL Adapter Array instruments expose a TTL-level serial port. The 3311 translates PC RS-232C to TTL, ensuring correct logic levels and robust communication for scripting, automation and data logging. Where It Fits 3644A/3645A/3646A Array 364X PSU series 3710A/3711A/3715A Array 371X DC loads Why It Matters Feature Why It’s Important What You Gain Correct Level Translation RS-232C uses bipolar signalling; Array ports expect TTL. Reliable framing, fewer comms errors, safe operation. Array-Specific Pin-Out Matches instrument wiring and addressing conventions. Drop-in setup; no custom harnesses. Binary Command Frames Simple 26-byte frames for control and readback. Deterministic timing and easy parsing. DB9 Connectivity Standard cabling with strain relief. Good EMI immunity and serviceability. Choosing Alternatives in the Series If you require USB on the PC side, choose Array 3312.

For multi-drop or long runs, use 3313 (RS-232↔RS-485) with 3314 (RS-485↔TTL). For GPIB racks, see 3315. Competitive Landscape Type Example Notes When To Prefer 3311 Brand-specific RS-232↔TTL Array 3311 Matches Array manuals and pin-outs. Controlling 364X/371X without rewiring. Generic RS-232↔TTL MAX32xx-based converters May need custom wiring; variable quality. When you need guaranteed Array compatibility. Other brand adapters e.g., Maynuo, B&K kits Sometimes isolated; different pin-outs. Use 3311 unless isolation or other brand required. Getting Started Set instrument address and baud (e.g., 9600 8-N-1) via the instrument menu. Use a straight-through DB9 RS-232 cable PC ⇄ 3311. The 3311 connects to the instrument’s TTL-level port. Send a status query frame to confirm communication, then enable remote control and output/load as needed. Wiring Quick-Start (364X & 371X) Important: The instrument port is TTL level. Do not connect a PC RS-232 port directly to the instrument. Always put the 3311 in-line. Minimum Signals You Need PC (DB9 DTE) Signal Direction Through 3311 Instrument Port (TTL) Notes Pin 3 (TXD) PC → Instrument Level-shifted RXD (TTL) Transmit from PC arrives at instrument RXD. Pin 2 (RXD) Instrument → PC Level-shifted TXD (TTL) Instrument TXD returns to PC RXD. Pin 5 (GND) Common — GND Shared reference; keep cables short and shielded. RTS/DTR hardware flow control is not used by these models; leave it disabled in software. If you get no replies, swap to a null-modem RS-232 cable only on the PC⇄3311 leg and retest. Serial Defaults (Factory) Model Family Baud Data Parity Stop Address Range 364X Power Supplies 9600 (menu-selectable 4800–38400) 8 None 1 0–31 371X Electronic Loads 9600 8 None 1 0–254 Image Placeholder — Simple DB9 ⇄ 3311 ⇄ Instrument Wiring Diagram Command Frames & Code Snippets These models use a simple 26-byte binary frame (header 0xAA, address, command, payload, checksum). Checksum is the unsigned sum of bytes 1–25 (mod 256). Below are safe “first actions” you can send to verify comms and toggle control. 364X Power Supplies — Read Status & Enable Output Query status: Command 0x81 (26-byte frame). Returns V, I, P and flags. Set control: Command 0x82 with Byte4 bits: b1=1 Remote, b0=1 Output ON. # Python 3 + pyserial import serial def make_frame(addr, cmd, payload=b""): frame = bytearray(26) frame[0] = 0xAA frame[1] = addr & 0xFE # instrument address frame[2] = cmd & 0xFF payload = (payload or b"")[:22] # bytes 4..25 available frame[3:3+len(payload)] = payload frame[25] = sum(frame[:25]) & 0xFF return bytes(frame) def send_recv(port, frame): with serial.Serial(port, 9600, bytesize=8, parity='N', stopbits=1, timeout=1) as s: s.write(frame) return s.read(26) ADDR = 0x00 # default # 1) Read PSU status resp = send_recv("COM3", make_frame(ADDR, 0x81)) # bytes 4..11 carry I (mA), V (mV), P (mW) little-endian groups I_mA = resp[3] | (resp[4] & 0xFF) << 8 V_mV = (resp[5] | (resp[6] & 0xFF) << 8 | (resp[7] & 0xFF) << 16 | (resp[8] & 0xFF) << 24) P_mW = resp[9] | (resp[10] & 0xFF) << 8 # 2) Remote + Output ON (Byte4 = 0b00000011) resp = send_recv("COM3", make_frame(ADDR, 0x82, bytes([0x03]))) print("PSU status read; output enabled.") To set limits and a voltage setpoint, use command 0x80 (max current, max voltage, max power, Vset). Start by reading status first to confirm framing and checksum handling. 371X Electronic Loads — Read Status & Turn Load On Query status: Command 0x91 (returns I, V, P and limit fields). Set control: Command 0x92 with Byte4 bits: b1=1 Remote, b0=1 Load ON. # Read 371X status then enable load ADDR = 0x