32
BMS 4 - 20 mA. Interface
Introduction
The Building Management System output option
for your controller provides a local BMS/PLC/
SCADA system with 4-20 mA signals proportional
to measured values, along with ON/OFF, clean
contact relays for Alarm, Flow, and the status of
all output relays.
Connections
All connections for BMS outputs are made via
the BMS Connector Board, cabled through spare
glands in the base of the enclosure. The BMS
Connector Board provides clear labelling of all 4-
20 mA and relay status outputs. The configuration
of the event outputs is discussed below.
4-20 mA Outputs
The BMS output option is available in 4 channel
(“C” series) or 8 channel configurations (8 channel
KPI only), with 4-20 mA signals proportional to
Temperature, Conductivity, pH and ORP, (along
with umPY and PIT rates on two metals for KPI 3
series controllers.)
It is recommended that a 250 Ohm sense resistor
is used at the BMS end of the connection for each
4-20 mA input – providing the BMS a 1- 5 volt DC
input across the range of measurement.
Note: In cases where the BMS requires a 2-10 volt
analog input (500 Ohm sense resistor), the 4-20
mA output may only be accurate up to 95% of the
maximum scale.
Event Outputs
Both the 4 channel (“C” Series) and 8 channel
(KPI 3) BMS options provide for ON/OFF, clean
contact switching for the current status of Alarm,
Flow and all available relay outputs.
Relay numbering is consistent within each family
of controllers, but dynamic across the full range,
so relay numbers may change depending on your
software configuration. The relay numbering for
each software configuration is easily obtained by
running the Test Outputs routine.
To enter the Test Outputs routine, press and hold
the
READ
key for 5 seconds. Now press the
ENTER
key to move the cursor to the
MAN/AUTO
selection. Press the
DOWN
arrow key to select
AUTO
Test outputs operation. The controller will
now cycle the output relays from REL1 through
all available relays for 5 seconds each. As each
output turns ON, the module and relay number are
displayed in the Test Outputs window as follows:
Line 3: RL1 – pH ON (5)
Flow and Alarm relays are common across all
controllers and are clearly labelled on the BMS
Connector Board.
The COMMON of each Event Output relay can
be supplied by a USER signal (+5, +12, etc, from
BMS into RLY(S) COM) or use an in12 volt
DC signal from the controller (for isolated inputs).
This selection is made by placing the jumper on
JP2 to 12V or RLYS COMM.
The jumpers on JP1 are connecting each Event
Output relay COMMON to the supply selected with
JP2 (to save on external wiring – in most cases a
common supply is sufficient). By removing these
jumpers the user can choose to individually wire
each relay, providing true clean contact switching
for all outputs.
2
System Configuration
2
System Configuration
