Solid-state relay board | Model 720RB/720RBDIN

Model 720RB Solid-state relay board
  • Sockets for 24 industry-standard SSR modules
  • 3 boards can be chained to support up to 72 SSR modules
  • Screw terminals for easy field wiring
  • Mountable via standoffs (720RB) or DIN rail (720RBDIN)
  • Connects to model 721

Model 720RB/720RBDIN is a legacy product and is not recommended for new designs. Legacy products are available but may have lead times up to 12 weeks and minimum order requirements. Use our Product Finder to find a comparable product or contact our Design Support Team.


The Sensoray Model 720RB Solid State Relay board provides optically coupled interfaces between low-level computer signals and high-power loads. Isolation is achieved by adding opto-coupled solid state relay modules. Up to twenty-four solid state releys may be added to the board.

Field connections

Two screw terminals are available for each of the twenty-four loads. The terminals will accept 16 to 24 AWG stripped wire.

Computer connections

Low-level signals from parallel adapters such as Sensoray's 7421 are connected to the 720RB with either an 80-conductor round cable or 50-conductor flat cable. The 50-conductor cable follows industry-standard pinouts for solid state relay boards. The 80-conductor cable brings 72 I/O signals from high capacity I/O adapters to one 720RB. Forty-eight of these signals may be diverted to two additional 720RB's so that 72 solid state relays may be controlled from a single adapter.

Mounting hardware

The standard 720RB is supplied with eight half-inch high threaded standoffs. Model 720RBDIN is supplied with mounting hardware for DIN rails.


Number of relay sockets24
Maximum relay voltage220 Vrms
Maximum relay current5 A
External voltage required to power input relays5 VDC
Wire sizes0.5 to 2.5 mm2
16 to 24 AWG
Dimensions(W x H): 18.715 x 3.800 inches

Model 720RB dimensions



File Version Type Size
Model 720RB Instruction Manual1.0.0PDF556 KB

Pricing & Ordering

Model Description Qty 1 Qty 2-9 Order Qty.
720RBSolid-state relay boardCallCall 
720RBDINSolid-state relay board, DIN rail mountableCallCall 
7501CCable, flat, 50 conductor, 18 inches$19$17
7501C1Cable, flat, 50 conductor, 1 meter$33$30
RELAY-G4IAC5Solid state relay, 120V AC input$19$19
RELAY-G4OAC5Solid state relay, 120V AC output$19$19
RELAY-G4IDC5Solid state relay, 10 to 32V DC input$19$19
RELAY-G4ODC5Solid state relay, 60V DC output$19$19

SENSORAY | 7313 SW Tech Center Dr. | Tigard, OR 97223 | 503.684.8005 | Email Us


Employment | Privacy Policy | Press Releases | Copyright © 1982-2018 Sensoray ~ All Rights Reserved