Johnson Controls M4-CGM Series, Installation Manual

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1. To prevent any possibility of damage from an
accidental short, remove power from the
controller .
2. Underneath the terminal block, in the small gap
between the bottom of the terminal block and
the circuit board, insert the flat blade of the
screwdriver.
Figure 10: Terminal block
3. To detach the left-hand side of the terminal
block, position the flat blade underneath the
terminal block to the left, and push down the
screwdriver handle. When you do this, you are
using the screwdriver as a lever to pry up the
terminal block.
4. To detach the right-hand side of the terminal
block, position the flat blade underneath the
terminal block to the right, and push down the
screwdriver handle.
5. If necessary, repeat steps 3 and 4 until the
terminal block is removed.
Removing the controller cover
Important: Electrostatic discharge can
damage controller components. Use proper
electrostatic discharge precautions during
installation, setup, and servicing to avoid
damaging the controller.
Important: Disconnect all power sources
to the controller before removing cover and
changing the position of any jumper or the EOL
switch on the controller. Failure to disconnect
power before changing a jumper or EOL switch
position can result in damage to the controller
and void any warranties.
The controller cover is held in place by four
plastic latches that extend from the base and
snap into slots on the inside of the housing
cover.
To remove the controller cover, complete the
following steps:
1. Place your fingertips under the two cover lift
tabs ( CGM09090 physical features ) on the sides
of the housing cover and gently pry the top of
the cover away from the base to release the
cover from the two upper latches.
2. Pivot the top of the cover further to release it
from the lower two latches.
3. Replace the cover by placing it squarely over
the base, and then gently and evenly push the
cover on to the latches until they snap into the
latched position.
Cover removed, EOL switch, and current
jumpers
Figure 11: CGM with cover removed showing EOL
switch and jumper positions
Setting the End-of-Line (EOL) switch
Each CGM controller has an EOL switch, which, when
set to ON (up), sets the controller as a terminating
device on the bus. See Figure 11 for the EOL switch
location. The default EOL switch position is OFF
(down).
Figure 12: End-of-Line switch positions
To set the EOL switch on a controller, complete the
following steps:
M4-CGM General Purpose Application Controllers Installation Guide 19