What is a Digital I/O option on the HI 4050?

The standard HI 4050 has three external digital inputs. The HI 4050 Digital I/O option card adds an additional three digital inputs and four digital outputs. The Digital I/O Option card can be located in the Option slot.  The DIO options function using DC voltage requires a DC voltage source between 5 to 30vdc.  I would suggest ordering the DC option, since you will have a DC voltage supply.  This will save problems by having the same earth ground potential for switching.

The Digital Inputs may be used to control commands like Tare, Zero, calibrating the instrument, or for any signal to indicate a change in state. You must map the Input to the destination desired, whether this is to trigger a command or just routed to a network data location.

The digital outputs are located under the Control drop-down list for Destinations. You select the digital output desired, then select the Source for this output to trigger on. For example, if you wanted output #1 to trigger when Setpoint #1 is met, you would select the Digital output #1 (HO0.0) for the destination and then select the Setpoint #1 output (HSI2) and map. Now when Setpoint #1 is met, it will turn on the output #1.

NOTE: The three standard digital inputs located on the main controller board J2 are activated by shorting pin 1, 2, or 3 input contact to the J2 pin 4 COM terminal with a dry contact switch or relay. On the DIO option card, the inputs are activated by applying 3-30 VDC between the Input terminal (pin 7, 8 or 9) and the GND terminal, pin 6 on the DIO option card's 9 pin connector. These two different activation methods are fixed and provide alternatives for application specific requirements.

This could be three push buttons connected to the standard External Inputs and three 24 VDC discrete signals from a PLC connected to the optional DIO card.   DO NOT USE 110VAC as a discrete input!  Previously you had to install a relay to activate the input contacts if sent from a PLC. Now that same discrete signal (voltage) can activate the DIO option card input without the expense of a relay. All standard and optional inputs are separate from all other inputs and any combination can be used and mapped.

The Digital Outputs on the DIO option card can be used to send a TTL weak 5vdc output (worst case minimum 3 V at 5mA out) voltage signal to a Relay Driver circuit to actuate mechanical relays. The digital output can also be used in pull to ground applications, current-limited to 250mA. This output can drive a relay as long as this 250 mA current level is not exceeded. To drive a relay directly with the DIO option card, attach a 3-30vdc power supply common to the GND terminal, pin 5. Connect the power supply plus side to the relay. Then connect the return side of the relay to a DIO output terminal. When the output activates it pulls the return side to ground and activates the relay coil. If the current limit is exceeded, there is a thermal fuse that will trip. This thermal PTC fuse is reset by disabling the output until the circuit cools (<1min).

Digital I/O Card Specifications:
All Inputs and Outputs must be mapped using the built in EtherNet web browser port from a laptop or PC. (See HI 4050 manual Chapter 6, Mapping)

Outputs
• Four non-isolated outputs
• 3-30 VDC pulled to ground, curren