45
• STANDARD RS-232: Continuously asserts RTS, CTS is required to initiate a transmit sequence,
but is ignored once transmitting has begun, uses
DCD to qualify receive data. This is the pro-
file used when
PROFILE = AUTO and an RS-232 communication interface is used with 920
V3.00.
•
3-WIRE RS-232: Continuously asserts RTS, CTS and DCD are ignored. This is the profile used
when
PROFILE = AUTO and an RS-232 communication interface is used with 920 V3.11+.
•
RS-485: Uses RTS and the Tx Delay timer, CTS and DCD are ignored. This is the profile used
when
PROFILE = AUTO and an RS-485 communication interface is used.
•
EXTERNAL MODEM: Uses RTS and the Tx Delay timer, ignores CTS, uses DCD to qualify each
receive data character and to sense an idle channel condition.
•
1200 BAUD MODEM: Uses RTS with a fixed 10 msec Tx Delay time, ignores CTS, uses DCD to
qualify each receive data character. This is the profile used when
PROFILE = AUTO,
BAUD RATE = 1200 and a MODEM communication interface is used.
•
300 BAUD MODEM: Uses RTS with a fixed 30 msec Tx Delay time, ignores CTS, uses DCD to
qualify each receive data character. This is the profile used when
PROFILE = AUTO,
BAUD RATE ¦ 1200 and a MODEM communication interface is used.
3.9.10 TX DELAY
Purpose: Allows a programmable delay between the receipt of a communications message and
the controller’s reply. In some applications, it may be necessary to delay the controller’s
response to an inquiry for a short period of time to allow external devices to start up, stabilize,
and/or synchronize.
Range: 0.00 to 2.50 seconds
Procedure: Set the amount of delay between the receipt of a message and the controller’s
response as required.
Note: This selectable
TX DELAY is only used if the PROFILE is set to either RS-485 or AUTO and an
RS-485 interface is installed.
3.10 Operator Console Functions
The following features are part of the controller’s programming, but are only used in conjunction
with the optional 920 Operator Console. For a detailed description of each of the console fea-
tures and operating instructions, refer to the separate document DigiTrace 920 Series HTC Oper-
ator Console—Installation and Operating Instructions (Tyco Thermal Controls reference
H56903) for the particular version of controller firmware that you are using.
3.10.1 PASSCODE
Purpose: The four-digit
PASSCODE feature prevents unauthorized users from modifying the con-
troller’s configuration parameters via a 920 Operator Console.
Range: 0000 to 9999
Procedure: Enter the desired
PASSCODE (in the “Common Setup” sub-menu) using the optional
920 Operator Console keypad. A
PASSCODE of 0000 disables the lockout feature and allows all
configuration parameters to be modified using the 920 Operator Console without requiring a
PASSCODE. Setting the PASSCODE to any other value will require the database to be unlocked, by
entering the correct
PASSCODE, prior to modifying any of the controller’s configuration parame-
ters using the optional 920 Operator Console.
Note: The
PASSCODE can only be edited if it is set to 0 or the database has been unlocked by
entering the proper
PASSCODE.
3.10.2 LOCK DATABASE
Purpose: If the
PASSCODE has been enabled (PASSCODE is not set to 0) and the user has
unlocked console modification access to the controller’s configuration parameters, the
LOCK
DATABASE
feature allows the user to re-lock this modification access once programming has
been completed.
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