VPFlowScope M
36
© 2016 Van Putten Instruments BV | MAN-VP-MPRO-UK | Revision:1602 | Date:20-10-2016
10
Electrical connections
NEVER USE AC POWER. THIS WILL VOID WARRANTY AND BRING
PERMANENT DAMAGE TO THE ELECTRONICS. THE INSTRUMENT MIGHT BE
DAMAGED BEYOND REPAIR.
CONNECT THE M12 CONNECTOR BEFORE POWERING UP THE
INSTRUMENTS.
The transmitter is equipped with a M12 5-pin connector which contains the power input, an
analogue output and a Modbus interface.
Pin
Signal
Wire color
1
+12...24 VDC
Brown
2
0 Volt
White
3
4..20 mA signal, active
Blue
4
RS485 A
Grey
5
RS485 B
Black
M12 5-pin female connector
Cabling
Shielded twisted pair cabling must be used for proper communication and measurement. Connect
shield to safety ground on one point. The thickness of the wires depends on the cable length. For
cabling below 300 meter | 1000 ft, use 20 awg. For longer runs use 18 awg or better.
Power supply
The input voltage is 12 to 24VDC. Make sure that the power supply is at least 12V at the connector.
Voltage drops will occur in long cables resulting in insufficient power. The display will notify you
when there is insufficient power.
10.1
4..20mA
An advantage of a current loop is that the accuracy of the signal is not affected by voltage drop
over the line. Even if there is significant electrical resistance in the line, the current loop transmitter
will maintain the proper current, up to its maximum voltage capability. The live-zero represented by
4mA allows the receiving instrument to detect some failures of the loop. An analogue current loop
can be converted to a voltage input with an external third party precision resistor.
The transmitter output is an active, non- isolated linearised current loop. This means that the + wire
is shared between power supply and the analogue output. A current will draw back from the
instrument to the power supply.
Cabling
3 wires are required to create a current loop. It is advised to use a shielded cable to prevent
electrical noise to affect the signal.
Ohm's law can be used to calculate the maximum distance. There are 2 parameters that needs to
be taken into account.
1. The voltage available is equal to the input voltage
2. The resistance depends on cable quality and length
