Analog Inputs - HORNER APG EXL10 OCS User Manual

MAN1029-08-EN_EXL10_UserManual
8.7

Analog Inputs

NOTE: See the datasheet for the EXL10 OCS model being used for jumper settings and see the appropriate page
in this manual (see Index) for details on how to use Cscape to configure the digital filtering.
The analog inputs on the EXL10 OCS allow voltage or current measurement from a variety of devices. The
voltage or current mode is set though jumpers on the unit and settings in Cscape. Each channel can be
separately configured for voltage or current mode.
The analog inputs have a digital filter that can be used to filter electrical noise that may be unavoidable in
some installations. The downside to digital filtering is the inputs will respond more slowly to sudden
changes in the actual input.
8.7.1 Thermistor Option for Special Orders
NOTE: The standard unit does NOT support thermistor.
Thermistor support is a factory option for Models 2, 3, and 4 only. Model 2 can support a two-channel
and four-channel thermistor. Models 3 & 4 support the two-channel thermistor only. Please refer to the
Thermistor Supplement, SUP0797, for thermistor specifications and implementation details.
8.7.2 Common Cause of Analog Input Tranzorb Failure, Models 2, 3, 4, & 5
If a 4-20mA circuit is initially wired with loop power but without a load, the analog input could see 24VDC.
This is higher than the rating of the tranzorb.
This can be solved by not connecting loop power prior to load connection or by installing a low-cost PTC in
series between the load and the analog input.
Figure 8.7 – Analog Input Tranzorb - Troubleshooting
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