Micromod RetroPAK: SLC Installation Manual - Manual (Page 62)

SLC RetroPAK Controller
COMMUNICATIONS CONNECTIONS
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• The instrument data base must be configured to provide RS-232 communication on the
built-in circuit; this is the default configuration.
When the built-in RS-232 circuit is being used for network communication, making a
connection to the front panel RS-232 port disables the network receive function so that the
instrument can receive data only from the device connected to the port. The transmit line is
not affected.
5.4 INSTRUMENT COMMUNICATIONS NETWORK (ICN) CONNECTIONS
An example of a typical ICN configuration with modular connections is shown in Figure 5-3.
5.4.1 Cable Requirements
The length of the ICN is the sum of the lengths of the physical two-wire bus between each
node on the ICN. If the network includes MOD 30 instruments, the length of any MOD 30
instrument cables between the nodes and the instruments must be included in the total
length. This length can be up to 2000 ft (609.6 m). Cable requirements for an ICN are
dependent upon the length of the ICN as described below.
• When the total length is 500 ft (150 m) or less, use 18 AWG (1 mm) shielded twisted pair
cable.
• When the total length is between 500 and 1500 ft (150 and 450 m):
- Entire length of the ICN must be at virtually the same potential and voltage drop
between any two points on ICN must not exceed 3V.
- Cable capacitance for an ICN must be between 18 and 25 pf/ft (60-83 pf/m).
• When the total length exceeds 1500 ft (450 m) or if the ICN must be routed through high
noise (EMI/RFI) environments, use 22 AWG (0.64 mm) shielded cable. If an ICN must
be run next to power lines or other unusual noise frequencies, contact your service
representative for assistance.
5.4.2 Addresses
Each device on an ICN must be assigned a unique address. Addresses are in the range of 0
through F hex (0 through 15 decimal). The address for the built-in circuit is configured
through the front face of the instrument in Device Setup (see IB-1800R-OPR Setup Section).
Addresses for modular circuits are set at the module as shown in Figure 5-3.