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DAM-8AO

DAM-8AO

RS-485 interface, 8 analog current outputs

Overview​

  • Industrial 8-channel analog current output module.
  • RS-485 interface and standard Modbus RTU protocol.
  • 12-bit resolution with precision resistors and zero-drift op-amps.
  • Isolated analog outputs suitable for VFDs, valve positioners, indicators, and other analog loads.
  • Dual isolation on the communication path with fuse, TVS, and gas discharge tube protection.
  • Stable and reliable for demanding industrial applications.

Specifications​

ItemDetails
Power6–36 V DC
InterfaceRS-485
Baud rates4800, 9600, 19200, 38400, 57600, 115200, 128000, 256000
Default format115200, N, 8, 1
Current outputs8 channels; range 0–20 mA; resolution 12-bit, 1 µA; accuracy ±0.03 mA
ProtocolStandard Modbus RTU
Slave address1–247
LEDSTA: solid on in Bootloader mode; slow blink when running; fast blink during communication
Dimensions121 × 72 × 34 mm

Hardware interface​

DAM-8AO
FunctionPinDescription
Power DC 6–36 VVINPositive
GNDNegative
CommunicationRS485 A+RS-485 A
RS485 B-RS-485 B
Current outputIOUT1–IOUT8Channels 1–8 current output (+)
AGNDAnalog ground (loop return / reference)

RS-485 bus wiring​

Most PCs have no RS-485 port. Use a USB-to-RS485 adapter; connect A to the module A terminal and B to B. For multiple devices, use twisted-pair shielded cable in a daisy-chain topology.

Analog output wiring​

  • Current output (AO): range 0–20 mA. From IOUTx through the load back to AGND to form the current loop. Keep load impedance within the instrument’s limit (commonly ≤500 Ω).

Operation demo​

Two tools are shown below. Either works for first bring-up; the web serial assistant is recommended for a quick start.

  • Web serial assistant: no install; full frame display and parsing; less intuitive for register data.
  • Modbus Poll: direct register access; easier to read setpoints; frames are not fully shown.
  • Open the serial debug tool, select the COM port, set 115200 N 8 1, and open the port.
  • Enable hex display and hex send, set checksum to ModbusCRC16, send 01 06 00 00 03 E8. When successful, AO1 outputs 1 mA and the frame is echoed back.
  • In the right panel, open Common modules, choose Write single holding register, and expand the command settings. Set the register address to the target output channel and the register value to the desired output, then click Send.
  • You can also use Write multiple holding registers to set multiple channels: specify the starting address and channel count, enter each channel value, then click Send.

Resources​

Documentation​

Tools​