Micro Technic PV-1700 Analogue inputs CN5, Differential measurement, Pin no Name, Configuration

Users Manual & Installation Guide

PV- 1800: Power supply module with GSM MODEM

Analogue inputs (CN5)

The PV-1800 and PV-1700 has 8 isolated analogue inputs accessible in a 10pin box header (CN5). Beside these inputs, there is also a +3.3V isolated voltage with common ground reference as the analogue inputs. This voltage can be used to power external conditioning circuitry - (max 10mA). Depending on the model – see section ordering codes – each input will have a full scale of 2.5V, 5.0V, 10V, or 20mA. The table shows the connector layout:

Pin no	Name	Pin no CDB-9F
1	Analogue GND	1
2	Analogue input#7	6
3	Analogue input#6	2
4	Analogue input#5	7
5	Analogue input#4	3
6	Analogue input#3	8
7	Analogue input#2	4
8	Analogue input#1	9
9	Analogue input#0	5
10	+3.3V Isolated

￿ ￿ ￿ ￿ ￿

+. ￿ ￿

￿￿1#+￿@￿5￿￿￿￿=&￿6

The input circuitry looks like this:

&￿)￿￿ ￿￿ ￿￿<

￿￿ ￿￿￿)@

￿! %! ￿￿￿￿￿

￿￿￿(￿￿

The analogue inputs are factory configured by choosing proper values for R1 and R2. In the table the values are shown for the different models. The input resistance is 1M￿ on all voltage input channels. The software interface is explained in section PV-1800 register interface.

Configuration		R1	R2
0	- 2.5V	0 ohm	1 Mohm
0	- 5 .0V	449 Kohm	449 Kohm
0	- 10.0V	741 Kohm	247 Kohm
0	- 20mA	0 ohm	125 ohm

Differential measurement

The analogue inputs can two by two be used for differential measurement. Inputs, which can make up a pair, are defined in the software. One of the wires, in each pair, is inside the ADC connected as a ‘negative’ input; the other as a ‘positive’ input. The common mode voltage on the ‘negative’ input must not exceed 0.5V in a 0 – 2.5V configuration and 1V in a 0 - 5V configuration. The combinations of the actual inputs used for differential measurement are shown in section - PV-1800 register interface. Also here it is described which input that is used as the ‘negative’.

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