IM620-1
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Note:
If a PC is connected to a level-2 controller, a level-1 controller must be set up to poll that level-2
controller so that the PC has access to the entire network. For information on how to set up the level-1
controller to poll the level-2 controller, see the operation manual for the particular controller being
used.
Direct Connection
An RS-232 communications cable kit allows a PC to directly connect to any MicroTech controller. It is
available from McQuay International. The cable has a female DB9 connector for connection to the
PC's 9-pin serial port. (If the PC has a 25-pin serial port, obtain an adapter.) The cable length is 12 feet.
If more length is required, a twisted, shielded pair cable can be spliced into the kit cable (see “Cable
Specification” below). If this is done, splice the conductors with crimp-type butt connectors (good) or
solder (best). Do not use wire nuts.
The maximum allowable cable length for direct connection
between the PC and a controller is 50 feet.
Cable Specification for Direct PC Connection
A properly terminated, twisted, shielded pair cable is required to directly connect a PC to a MicroTech
controller. The cable must meet the following minimum requirements: twisted, shielded pair with drain
wire, 300 V, 60°C, 20 AWG, polyethylene insulated, with a PVC outer jacket (Belden 8762 or
equivalent). It must also be properly terminated to an AMP plug on one end and a female DB9 or
DB25 connector on the other. See Figures 9 and 10 for cable pinouts.
The DB9 or DB25 connector is for connection to a 9-pin or 25-pin serial port on the PC. Note that
some local codes or applications may require the use of plenum rated cable.
Do not install the cable
in the same conduit with power wiring.
Note:
A factory-assembled cable that meets the above specification is provided with the PC
Communications Cable Kit. This cable has a DB9 connector.
Figure 9. RS-232 Cable Pinouts for 9-Pin Serial Ports (AMP Connector)
Signal
Pin
Female DB-9
CTS
8
RTS
7
DSR
6
GND
5
DTR
4
TD
3
RD
2
DCD
1
Signal
Pin
AMP Plug
–
6
GND
5
RD
3
–
2
TD
1
White
Black
Shield
a0109
