2.4.2 Digital Status Outputs

2.4.2 Digital Status Outputs

The M460H has four digital status outputs for indicating error and operational status conditions. These outputs are in the form of opto-isolated open-collector transistors. They can be used to drive status LED’s on a display panel or interface to a digital device such as a Programmable Logic Controller (PLC).

Figure 2-4 shows the most common way of connecting the digital outputs to an external device such as PLC. Note: Most devices, such as PLC’s, have internal provision for limiting the current that the input will draw from an external device. When connecting to a unit that does not have this feature, external dropping resistors must be used to limit the current through the transistor output to 50mA or less.

See Chapter 7 for details on using the Status Outputs for diagnosing sensor and system- level malfunctions.

Table 2-1 below describes the function of the status outputs.

Table 2-1 Digital Status Output Pins

Label

Name

Operation

STATUS OUT 1

Sensor O.K.

Normally On

STATUS OUT 2

Invalid Reading

Normally Off

STATUS OUT 3

Lamp Low

Normally Off

STATUS OUT 4

Cell Dirty

Normally Off

STATUS OUT 5

Auto-Zero Error

Normally Off

STATUS OUT 6

Spare

Undefined

STATUS COM

Common Pin for

N/A

 

all Status Outputs

 

M454

 

Programmable Logic

 

 

Controller or other device

 

 

+5V

Digital

Output #1-4 (Collector)

Digital

 

 

Input

Digital Output Common (Emmiter)

Opto-Isolator

 

Ground Provided

 

by PLC

Figure 2-4 Digital Output Connections

P/N 03662D Teledyne API Model 460H O3 Monitor Operator Manual - Page 15

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Teledyne 460H Digital Status Outputs, 1 Digital Status Output Pins, Label, Name, Operation, 4 Digital Output Connections