
Checklist for GR 2400/1400 System Start Up
1) Verify that the system is complete against the bill of
materials. Check that all switches and photocells listed
have been included and are now mounted.
2) Check that the system power has been connected to the
correct terminal on the Transformer input block. (120 or 277
volts.) Make sure that this is a dedicated circuit rather than
in parallel with a load that might blow and pull the whole
system down.
3) Make sure that the Bus has been properly connected up:
a) Ensure that the bus has been run in a straight line as
shown at the bottom of the page. There should be no
"spurs" of more than a few feet (2-3). The wire must be Cat
5. Switches on very long runs may need additional wires to
boost the voltage at the switch. If suspicious measure the
voltage at the switch after step 4. Volts must be above 9
volts dc between the 0 and +12 volt 2 pin connectors.
b) This should have been done as the connecting cables
between each point were made up. If not then go through
the entire bus with a cable tester. Testing each section of
cable to make sure there is continuity and no problems with
the data wires.
2#18AW
G
32 Relay
16 Zone
Master
Panel
16 Relay
8 Zone
Slave
Panel
Digital Switch-
es
Photocell
Control Card
Outdoor
Photocell
Terminate!
Terminate
Appendix II
Page 59
c) Make sure that the system is NOT POWERED. There
should not be any power on any control card. Having veri-
fied this, plug in the bus to all boards Make sure that the
bus is
terminated
at the far end. (Note: If terminator short-
ing jumpers are lost call the factory for the location of a
secret spare.) At the first board on the bus remove the ter-
minating jumper and measure Ohms between 2 and 3.
(Most relay panels have at least one “1234" connector
which allows access to the 4 wires of the bus so that ohm
readings can be taken. If “1234" connectors are not present
there will be “TEST” points that allow an ohm reading to be
taken. Readings should be taken at this connector. Should
be approximately 120 ohms plus the ohms due to the wire.
(Expect about 48 ohms per 1000ft of #24 awg wire plus the
120 ohms at the far end.) This is a chart of expected values
measured on the data pair ONLY.
500 Ft with single terminator
144 ohms
1000 ft with single terminator
170 ohms
2000 ft with single terminator
220 ohms
3000 ft with single terminator
270 ohms
4000 ft with single terminator
320 ohms
5000 ft with single terminator!!!!
370 ohms
More than 4000 ft the bus must be split. Call Tech Support!
Remember to replace the terminator at the begining of the bus!
65