Aeroflex Circuit Technology

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SCDCT2553 REV B 8/6/99 Plainview NY (516) 694-6700

OVERRIDE TRANSMITTER SHUTDOWN (00101)

MESSAGE SEQUENCE - OVERRIDE SHUTDOWN - STATUS

This command is only used with dual redundant bus systems. The CT2553 responds with status. At the end of the status transmission, the

CT2553 re-enables the transmitter of the redundant bus. If the command was broadcast, the broadcast received bit is set and status

transmission is suppressed.

ERROR CONDITIONS

1. Invalid Command. No response, command ignored.

2. Command Followed by Data Word. No status response. Bits set: message error (SW), High Word Count (BIT Word).

3. T/R bit Set to Zero. No status response. Bits set: message error (SW), T/R Error (BIT Word).

4. Zero T/R bit and Broadcast Address. No status response. Bits set: message error, broadcast received (SW), Illegal Mode Code, T/R

Error (BIT Word).

INHIBIT TERMINAL FLAG BIT (00110)

MESSAGE SEQUENCE - INHIBIT TERMINAL FLAG * STATUS

The CT2553 responds with status and inhibits further internal or external setting of the terminal flag bit in the status register. Once the

terminal flag has been inhibited, it can only be reactivated by an Override Inhibit Terminal Flag or Reset RT command. If the command was

broadcast, the broadcast received bit is set and status transmission is suppressed.

ERROR CONDITIONS

1. Invalid Command. No response, command ignored.

2. Command Followed by Data Word. No status response. Bits set: message error (SW), High Word Count (BIT Word).

3. T/R bit Set to Zero. No status response. Bits set: message error (SW), T/R Error (BIT Word).

4. Zero T/R bit and Broadcast Address. No status response. Bits set: message error, broadcast received (SW), T/R Error (BIT Word).

OVERRIDE INHIBIT TERMINAL FLAG BIT (00111)

MESSAGE SEQUENCE - OVERRIDE INHIBIT TERMINAL FLAG * STATUS

The RTU responds with status and reactivates the terminal flag bit in the status register. If the command was broadcast, the broadcast

received bit is set and status transmission is suppressed.

ERROR CONDITIONS

1. Invalid Command. No response, command ignored.

2. Command Followed by Data Word. No status response. Bits set: message error (SW), High Word Count (BIT Word).

3. T/R bit Set to Zero. No status response. Bits set: message error (SW), T/R Error (BIT Word).

4. Zero T/R bit and Broadcast Address. No status response. Bits set: message error, broadcast received (SW), T/R Error (BIT Word).

RESET REMOTE TERMINAL (01000)

MESSAGE SEQUENCE - RESET REMOTE TERMINAL * STATUS

The CT2553 responds with status and internally resets. Transmitter shutdown, mode commands, and inhibit terminal flag commands will be

reset. If the command was broadcast, the broadcast received bit is set and the status word is suppressed.

ERROR CONDITIONS

1. Invalid Command. No response, command ignored.

2. Command Followed by Data Word. No status response. Bits set: message error (SW), High Word Count (BIT Word).

3. T/R bit Set to Zero. No status response. Bits set: message error (SW), T/R Error (BIT Word).

4. Zero T/R bit and Broadcast Address. No status response. Bits set: message error, broadcast received (SW), T/R Error (BIT Word).

RESERVED MODE CODES (01001-01111)

MESSAGE SEQUENCE = RESERVED MODE CODES * STATUS

The CT2553 responds with status. If the command is illegalized through an optional PROM, the message error bit is set and only the status

word is transmitted.

ERROR CONDITIONS

1. Invalid Command. No response, command ignored.

2. Command Followed by Data Word. No status response. Bits set: message error (SW), High Word Count (BIT Word).

3. T/R bit Set to Zero. No status response. Bits set: message error (SW), Illegal Mode Code (BIT Word).

4. Zero T/R bit and Broadcast Address. No status response. Bits set: message error, broadcast received (SW), Illegal Mode Code (BIT

Word).

Table 6 – Mode Codes (continued)