Installation
Operating Manual EM-PQ 2300
19
A 120
Ω terminating resistor must be installed at each end of the bus by connecting it between the terminals
A
and
B
. In bus systems with fewer than 4 devices, a 1 k
Ω resistor must also be connected between the terminals
A
and
. The resistors must be rated at 250 mW.
NOTE!
The bus shielding (
) must be earthed at one point in the bus system. If earthing has not already
been done at some other point, it can be done at the EM-PQ 2300.
However, the
bus must only be earthed at one point
!
If this is not done, damage can occur to the bus interfaces of all connected devices, and data
transmission can be disrupted.
NOTE!
A 120
Ω terminating resistor must be installed at each end of the bus by connecting it between the
terminals
A
and
B
. In bus systems with fewer than 4 devices, a 1
kΩ resistor must also be
connected between the terminals
A
and
. The resistors must be rated at 250 mW.
Without terminating resistors, the data transmission can be disrupted. It is also possible that no
functioning data link can be established between the devices.
Recommended cable types:
Surge impedance 100
–120
; Ø 0.5 mm²; shielded twisted pairs;
Types:
IBM Twinax
EIB bus cable
Lapp Unitronic J-2Y (ST) Y
Siemens YCYM 4
×
2
×
0.8 or PYCYM 4
×
2
×
0.8
NOTE!
A mixing of different cable types must always be avoided.
The use of different cable types can disrupt data transmission. It is also possible that no
functioning data link can be established between the devices.
5.1.5 Display bus
The EM-PQ 2300 can be connected by a suitable bus cable to an optional
EM-FD 2500 Display instrument, which enables the EM-PQ 2300 to show
its measurement readings, graphs, alarms and operating structures.
Figure 8: EM-FD 2500 Display
Other suitable FRAKO Energy Management devices can also be
connected to this bus, provided that the technical specifications of the bus
system are complied with in the cable connections.
The bus system used is the CAN bus.
The EM-FD 2500 Display obtains both its instrument power and its data via the four poles of its male connector.
The connector poles of the EM-FD 2500 Display are assigned as follows:
-
Poles 1 and 4 (outer): instrument power = first twisted pair
-
Poles 2 and 3 (inner): data transfer = second twisted pair
The cable shielding can be connected to pole 4.
If a suitable cable is used, the length of the complete bus system can be up to 40 m.
