Analog Signal Input
Verbatim Owner's Manual
B-11
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B.1.9
If Analog Inputs Do Not Work Correctly
Recheck programming settings, especially the Input Signal Type setting. Verify
that the polarity of your input connections is correct.
In the case of 4-20 ma input, does the spoken value always reflect a 0 ma signal
level? If so, the problem is presumably with the connection or the signal source.
Use a DC meter to verify that both sides of the offending input are within 10
VDC of ground. A 4-20 ma current loop input should give a meter reading of
about .07 volt per milliamp of current as measured across the two signal input
terminals.
Are other instruments included in the same current loop? If they read correctly,
temporarily disconnect the input to the Verbatim Autodialer. This should throw
the readings of the instruments off scale. If there is no such effect, your wiring
is not including the Verbatim autodialer in the loop. Verify that the type of
signal source agrees with the physical configuration on the VAN card according
to the marking on the back of the card.
B.1.10
Troubleshooting Analog Grounding Problems for
Verbatim Analog
The most common analog signal type in use in the Verbatim marketplace is
current loops, wherein the signal is a controlled DC current ranging from 4 to
20 milliamperes.
The loop consists of a current transmitter (consisting of a transducer and a
supporting power supply which may or may not be packaged into one unit), and
one or more receiving devices which measure and respond to the current signal
they detect on the loop. The power supply voltage is typically 24 volts DC.
The terms "transducer" and "transmitter" are used interchangeably. The
transmitter's job is to ensure that the current level accurately reflects the
physical parameter which the transducer is measuring (typically a pressure or
liquid level), regardless of what impedance it sees in the loop.
In order to do this, it presents whatever voltage across its terminals is needed to
achieve the correct current flow. This voltage must be great enough to
accommodate the total resistance in the loop. The typical resistance
contribution presented by each receiving device is 250 ohms. However, the DC
resistance presented by the Verbatim analog inputs is around 70 ohms (49.9
ohm precision resistor plus two 10 ohm surge standoff resistors).
In theory, all elements in the loop are isolated from any connection to electrical
ground. This is intended to eliminate concerns about errors in the signal caused
by conflicting ground or other conflicting connections.
Summary of Contents for Verbatim
Page 1: ...Verbatim Owner s Manual Owner s Manual...
Page 14: ...Overview 1 4 Verbatim Owner s Manual...
Page 22: ...Installation 2 8 Verbatim Owner s Manual...
Page 24: ...Programming and Testing 3 2 Verbatim Owner s Manual Front Panel Keys and Indicators Diagram...
Page 34: ...Recording Voice Messages 4 6 Verbatim Owner s Manual...
Page 80: ...Using the Alarm Ready Schedule Feature 7 12 Verbatim Owner s Manual...
Page 82: ...Maintenance Testing and Battery Replacement 8 2 Verbatim Owner s Manual...
Page 94: ...Verbatim Series SFP Autodialer A 8 Verbatim Owner s Manual...
Page 104: ...Analog Signal Input B 10 Verbatim Owner s Manual...
Page 108: ...Analog Signal Input B 14 Verbatim Owner s Manual...
Page 114: ...Remote Supervisory Control Output C 6 Verbatim Owner s Manual...
Page 118: ...Printer Options D 4 Verbatim Owner s Manual...
Page 126: ...Data Acquisition Central Data Logging E 8 Verbatim Owner s Manual...
Page 155: ...Cabling Diagrams Verbatim Owner s Manual G 1 G Cabling Diagrams...
Page 156: ...Cabling Diagrams G 2 Verbatim Owner s Manual G 1 RACO VSER 01 Serial Cable Connection Diagram...
Page 166: ...Verbatim Floobydust H 4 Verbatim Owner s Manual DC Power Connection Diagram AJ1 JB8 MINI PLUG...
Page 174: ...Verbatim Floobydust H 12 Verbatim Owner s Manual Heater Thermostat Mounting and Wiring Diagram...
Page 188: ...Verbatim Floobydust H 26 Verbatim Owner s Manual Motherboard Component Diagram...
Page 189: ...Verbatim Floobydust Verbatim Owner s Manual H 27 Jumper Block Diagram...
Page 192: ...Verbatim Floobydust H 30 Verbatim Owner s Manual...
Page 200: ...Verbatim Autodialer Specifications I 8 Verbatim Owner s Manual...
Page 201: ...Worksheets Verbatim Owner s Manual J 1 J Worksheets...
Page 236: ...Glossary Glossary 8 Verbatim Owner s Manual...
Page 244: ...Verbatim Owner s Manual...