Specifications

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Because the controllers are “stand alone” they do not need PC supervision for their
normal function, and will continue to control the process unaffected by failure of any part
of the communications loop.
When used with the Model 518 Chamber, the Temperature Microprocessor & Humidity
Microprocessor COMM PORTS are wired together, in parallel. One RS-485 COMM
PORT, common to both controllers, is located on the ‘Side Interface Panel’ of the Model
518 Chamber.
3.4.1 Set-up and Installation
(Refer to pp. 2 & 3 in the CALCOMMS Manual)
3.4.1.1 RS 485 COMM PORT
RS-485 is a half duplex serial communications link and is the standard
most commonly used for industrial applications due to it’s high noise
immunity and multi-drop capability. It enables a PC to communicate with
up to 32 instruments over distances of over 1200 meters, and requires the
addition of an RS-485 interface card, or a separate RS-232/485 converter.
The RS-485 COMM PORT is a 9-pin subminiature-D female connector
located on the ‘Side Interface Panel’.
3.4.1.2 RS-232/485 Converter
The RS-232/485 Converter will not be needed if the computer is outfitted
with an RS-485 interface card.
The converter is a 9-pin / 9-pin in-line style connector. The converter is
gray and bears the label ‘ RS-232 TO RS-485 / Model 485SDD9R’.
3.4.1.3 Connections
1. Connect the supplied 9-pin male/female sub-D cable to the RS-485
COMM PORT on the ‘Side Interface Panel’.
2. Connect the other end of the cable to the ‘RS485’ side of the RS-
232/485 converter.
3. Connect the ‘RS232’ side of the converter into the appropriate
Comm Port on the PC.
3.4.1.4 Software Installation