CHPA SERIES
3-4
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Table 3-1. Serial Remote Interface Pin Assignment (J6) (continued)
Pin #
Signal Name
Remarks
4
Receive Data (-)
Data received by CHPA (RS-422/485)
5 Signal
Ground
6
Receive Data (+)
Data received by CHPA (RS-422/485)
7 Not
used
8 Not
used
9
Send Data (+)
Data sent out of CHPA (RS-422/485)
Table 3-1 Note:
The Serial Remote Interface uses a protocol and command set very similar to the Computer Interface port. Refer to that portion of
this section for programming reference. Additionally, the Serial Remote port includes the following command:
ASCII Byte
Decimal
Command Definition
\
92
Set Control Mode. If the CHPA is in either Remote or CIF
mode, the Serial Remote port may shift control between
Remote and CIF. To specify Remote, follow the command with
the number 0 (ASCII 30 Hex. 48 Dec.); to specify CIF, use the
number 1 (ASCII 31 Hex.49 Dec.).
3.4 RF Switch System Interface
The RF Switch System interface provides the relay-reported CHPA status and RF Inhibit
command required by a waveguide switch controller. Three relays provide CHPA status: Low
RF, Fault, and Sum Fault. The relay coil is de-energized to indicate a condition; this fail-safe
mode means that a loss of power will provide condition indications on all relays. The only
command on this interface, RF Inhibit, is active at all times and is not subject to the control
mode hierarchy. If an RF Switch port RF Inhibit is issued while the low RF Relay indicates a low
RF condition, the Low RF Relay will continue to indicate Low RF. Once the RF Switch Port RF
Inhibit disappears, the Low RF Relay will report existing conditions.
3.4.1 Relay
Definitions
The Low RF Relay indicates that the CHPA’s RF output is below the Low RF Alarm level or that
the CHPA is in the Fault state; a waveguide switch system usually uses this information to
trigger automated switching action. The Low RF Relay may be toggled to either Flexible mode
or Rigid mode via the front panel under the RF TRIP LIMITS menu selection. Press the MENU
button until the selection RF TRIP LIMITS is displayed. Press the FUNCTION button until the
selection LOW RF RELAY is displayed; use the arrow keys to select either FLEX (for Flexible
mode) or RIGID (for Rigid mode).