Cooper Kyle Form 4C - Page 33

33
S280-77-4
!
SAFETY
FOR LIFE
Digital Communications (cont’d)
Security Limits
Access Factory
Code Write Read Scroll High Low Incr Parameter Settings
83 0 0 NO 2 0 1 Real-Time Digital Communications 2
Port Handshake (Transmit Disable Delay)
Mode Code
0 = None
1 = Not Applicable
2 = Modem Control (50 mS OFF)
3 = Modem Control (0 mS OFF)
4 = Modem Control (10 mS OFF)
• The transmit/receive handshaking method allows
adaptability of different types of communication sys-
tem interfaces with the Form 4C control. When using
modes 2 through 4, the handshake out signal is
used as the transmit enable. The handshaking input
signal is ignored.
• Code 83 and Code 85 affect the bandwidth and effi-
ciency of the communication system. Adjusting
Codes 83 through 85 to the minimum operable
delays, maximizes the efficiency of the communica-
tion system.
• Mode 0: No handshaking signals. This mode is used
for direct connection between the Form 4C and a
personal computer. It may also be used with an RTU
for point-to-point applications.
• Mode 1: Not applicable. Used for internal purposes
only.
• Mode 2: Transmit Enable with 50 millisecond trans-
mit disable delay. This is applicable to the three
available interface cards: fiber optic, user-powered
EIA-232, and 202T modem interface. Mode 2 is used
where a transmit enable (push-to-talk) is required as
part of the handshaking.
Applications include using the transmit enable to key
a radio along with using a fiber-optic ring. Transmit
enable is required for control of the fiber-optic ring.
• Mode 3: Transmit Enable with 0 millisecond transmit
disable delay. This application is identical to Mode 2
without transmit disable delay. Mode 3 is used for
fiber optic applications where radio squelching is not
a concern.
• Mode 4: Transmit Enable with 10 millisecond trans-
mit disable delay. This application is identical to
Mode 2 but with a 10 millisecond transmit disable
delay. Depending on the communication equipment,
a 10 millisecond transmit disable is adequate com-
pared to 50 milliseconds in Mode 2 and results in a
shorter bandwidth and improved efficiency.
Transmit
Enable
Transmit
Disable
Data
Message
CODE 85
Transmit Enable Delay
P
rogrammable from 0-425 mS
in 1mS increments
CODE 83
Transmit Disable Delay
Selectable at 0, 10, or 50 mS
Access Code 83 Transmit
Handshake Mode Handshaking Disable Delay
0 No Not Applicable
1 Not Applicable Not Applicable
2 Yes 50 mS
3 Yes 0 mS
4 Yes 10 ms
TABLE 6
Handshaking and Transmit Disable Delay
Summary applicable to Access Code 83
Figure 7.
Data transmission from the Form 4C control to the
communication system for handshaking applica-
tions.