9.3.6
SSCA Configuration
For the six serial communication channels:
•
Jumpers JP1A through JP6A apply or remove termination resistors between signal lines A and B
•
Jumpers JP1B through JP6B apply or remove termination resistors between signal lines C and D
•
Jumpers JP1R through JP6R select whether the return has a resistive or capacitive connection to SCOM.
All other configuration is performed from the ToolboxST application. Electronic selection of the serial communications
method, either RS-232C, RS-422, or RS-485, is internal to the I/O pack.
9.3.6.1
RS-232C (Point-to-point)
•
It is often not desirable to have a hard ground of the Ret signal path on both ends of a cable. SSCA includes jumper
selectable grounding options for each of the six Ret lines.
•
The line may be grounded through a 100 Ω resistor or, through a 0.01 uF capacitor / 1 M Ω resistor parallel combination.
•
If the device attached to SSCA features a hard ground of the Ret line then the capacitive ground should be selected on
SSCA. If there is not a hard ground on the connected equipment then the resistive ground (default position) should be
selected on SSCA.
•
Ret ground jumpers are identified on SSCA as JP1R through JP6R. Positions are displayed as RES and CAP for resistive
and capacitive return connection. The jumpers are clearly labeled on the SSCA.
In general, if the information on third-party side hardware configuration (hard ground or not) is available during pre-FAT,
keep Ret with resistance ground. The JP#R stays connected to RES (Default), and configuration must match the ToolboxST
application configuration, as displayed in the following diagram.
Note
If a computer is connected as a test simulation device (with MODSIM running), the wire from Pin-5 of D-Type
connector must be connected to SCOM1.
Terminal Board Screw Connections
Channel
SCOM
A
B
C
D
RET
Channel 1
26
28
30
32
34
36
Channel 2
25
27
29
31
33
35
Channel 3
13
15
17
19
21
23
Channel 4
14
16
18
20
22
24
Channel 5
02
04
06
08
10
12
Channel 6
01
03
05
07
09
11
Protocol
A
B
C
D
Cable Length
RS-422
TX+
TX-
RX+
RX-
Up to 305 m (1000 ft)
RS-485
TX/RX+
TX/RX-
Jumper from A
Jumper from B
Up to 305 m (1000 ft)
RS-232C
DTR/RTS
TX
CTS
RX
Up to 15 m (50 ft) or 2500 pF
296
GEH-6855_Vol_II
GEH-6855_Vol_II Mark VIeS Functional Safety Systems Volume II
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