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Synapse remote I/O module

 7bit Synapse remote I/O module

The Synapse module (further reffered to as 'module') is produced under 7bit trademark and designed for data aquisition from discrete sensors and 1-Wire temperature sensors, as well as load control with digital outputs.

The module has 2 Ethernet interfaces (working in a “bridge” mode) for LAN connection and supports Modbus TCP & MQTT protocols. The enclosure is for panel / DIN 35 mm mount.


Power: 220VAC
Ethernet mode DHCP client / static IP
Digital Inputs 8 (24Vdc)
Counter inputs (non-volitile) 8 (digital inputs can be counting inputs with max. frequency of 1kHz, with anti-jitter filter of a 1ms step )
Digital Outputs (2 groups x 4 outputs (symistor or relay ))2A
1Wire bus up to 32 sensors, cable length up to 200 мeters
Power supply for 'dry contacts' yes
Enclosure protection IP40
Dimensions (HхWхD): 145х90х40 mm.
Weight: 240 g.

Modbus registers map

There are 1000 HR registers available for the user, some of them are reserverd for special functions:

Holding Registers
000-999: (F-RAM)
Discrete Inputs
DI0 ~ 7 Digital input state 0 ~ 7
HR20 ~ 27 Digital filter. (DI 0 ~ 7)
C0..7 Digital outputs 0..7
Safety state
HR35 Keep previous outputs state after restaft, 0 - off, 1 - on
Predictive maintenance registers
HR0 ~ HR14 countung input (DI 0 ~ 7) dw, high word comes first
HR60 ~ HR 74DI 0 ~ 7 time on totalizers
PWM for triac outputs
HR111 ~ 118 DO1 ~ 8 PWM duty cycle

* this option available for the SSR outputs

HR30 power-ups counter
HR31 uptime in seconds (high)
HR32 uptime in seconds (low)
IR0 ~ IR31 1-Wire temperature 1 (-1000° - sensor failed or not connected)
HR33 Total sensors quantity or Init** (writing 0 to HR33 clears the enumeration)

Auto enumeration for 1-Wire sensors

Each DS18B20 has their own unique serial number. Using a special search algorithm, the Synapse finds and saves the enumeration scheme for the sensors found in the static memory. New sensors still can be added to the existing enumeration by

  • powering on or resetting the module
  • writing non-zero value into HR33 register

Modbus map csv-file

For the convinence, a module register map is provided from this link to import in the WebHMI project.