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Relay Drivers / 7321
7321 SPST Single-Channel Solid-State Relay

Overview

The 7321 is a single-channel, solid-state relay that allows a datalogger to control one or two dc devices.

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Benefits and Features

  • Generally more economical for one or two channel applications as opposed to a 4- or 6-channel relay driver

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Detailed Description

The 7321 is the same device as CRYDOM's model D1D07 that's distributed through Newark Electronics and others. One datalogger digital port controls each relay.

Normally Open

This relay is usually operated in the Normally Open state. In this state, when the digital port is set high, the relay is closed. Wiring for this situation is as follows:

Datalogger Terminal Relay Screw Terminal
ground 4
digital port
(i.e., C1, C2,...)
3

Normally Closed

The 7321 can also be operated in the Normally Closed state. In this state, when the digital port is low, the relay is closed. Wiring for this situation is as follows:

Datalogger Terminal Relay Screw Terminal
5V 3
digital port
(i.e., C1, C2,...)
4

Specifications

Control Voltage 3.5 to 32 Vdc
Control Current 1.6 mA (@ 5 Vdc)
Rated Current/Voltage 7 A (@ 100 Vdc)

Compatibility

Datalogger Considerations

Compatible Contemporary Dataloggers

CR200(X) Series CR800/CR850 CR1000 CR3000 CR9000X

Compatible Retired Dataloggers

CR500 CR510 CR10 CR10X 21X CR23X CR5000 CR7X CR9000
* *

Compatibility Notes:
*The CR500 and CR510 only have one digital port capable of providing control signal.

Frequently Asked Questions

Number of FAQs related to 7321: 2

  1. The following relay devices can be used with the CR800 and the CR850:

    • 7321
    • A6REL-12*
    • A21REL-12
    • LR4
    • SDM-CD8S
    • SDM-CD16AC
    • SDM-CD16S

    The CR800 and the CR850 can also be used with a wide variety of third-party relay devices.

    *Because the CR800 and the CR850 only have four digital ports, they do not have the ability to switch all six of the relays on the A6REL-12.

  2. Either the PortSet() or the WriteIO() instruction can be used to open and close the 7321 relay. These instructions are commonly used in conjunction with an IfThen/EndIf construction.

    In this first example, the program closes the relay at the top of a 60 second interval and then opens the relay after ten seconds:

    BeginProg

                Scan (1,Sec,0,0)

                            If IfTime (0,60,Sec) Then

                                        PortSet(1,1)

                            ElseIf IfTime (10,60,Sec) Then

                                        PortSet(1,0)

                            EndIf

                NextScan

    EndProg

     

    In this second example, the WriteIO() instruction is used to close the 7321 relay based on the measured panel temperature:

    Public PTemp

    BeginProg

                Scan (1,Sec,0,0)

                            PanelTemp (PTemp,_60Hz)

                            If PTemp > 25 Then

                                        WriteIO (&B00000001,&B00000001)

                            Else

                                        WriteIO (&B00000001,&B00000000)

                            EndIf

                NextScan

    EndProg

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