Xylem Expert 700 - Manual (Page 5)

Manual
GB Manual Expert 700 0712
As our products are continuously improved, we reserve the right to make
any change in the stated specifications and dimensions without prior notice.
MJK Automation A/S
Byageren 7
DK-2850 Naerum
Denmark
Tel.: +45 45 56 06 56
Fax: +45 45 56 06 46
[email protected]
www.mjk.com
Electrical mounting
Cable length vs. supply voltage
The cable can be lengthened with any type of cable using connection box 202922.
Although the measuring signal is generally not sensitive to electrical noise, we recommend the use of a screened
cable. This is especially important around VFD’s and motor power cables.
Ensure that no moisture can enter the pressure compensation tube inside the cable.
The length of the cable is only limited by the total resistance (A) of the cable conductors + the input impedance of
the analog input on the MJK 704, MJK 713, PLC etc. (typically 10 to 100
Ω
) and the available supply voltage
(typically 24 V DC).
Designation of wires, cutting & stripping the cable
The factory delivered cable has the wires marked with colours as to the table below.
Do NOT connect any of the programming wires as it may damage the transmitter. The programming wires should
be cut off in different lengths to prevent them from short circuit.
Take care not to block or squeeze the air pressure compensation tube
Example:
The nominal resistance for 1 conductor in a transmitter cable is 0,036
Ω
/m. A standard 12 m cable will therefore add
2 x 0,036 x 12 = 0,86
Ω
to the loop resistance. If the analog input has an impedance of 50
Ω
, the total resistance will
be approx. 51
Ω
.
Necessary supply voltage in relation to the total loop resistance.
(A) Total loop resistance [
Ω
]
(B) Supply voltage [V DC]
According to the diagram above, approx. 12 V DC will be sufficient