ALARM-24 Series User Manual P/N 821542 Rev-A
20
© 2003 Wohler Technologies Inc. ALL rights reserved
Section 3: Technical Information
RS232 Status and Control
1) Interface Type
The RS232 connector on the ALARM units is a female DB9, configured for Data Communications Equipment (DCE). This port
will connect directly to a COM port on an IBM compatible computer with a "straight through" 9-way RS232 cable.
2) Serial Form
Data is sent and received without any handshaking using the following data format:
Rate:
9600 Baud
Format:
8 bits
Stop Bits:
1
Parity:
None
3) Messages from ALARM unit
Data is sent out of the ALARM units formatted as ASCII Hex, most significant data first, length is 32 bits, the string is terminated
by Carriage Return, Line Feed.
The 32 bit message contains an 8 bit Command Code (B31..24) and 24 bits of Channel Data (B23..0).
Command Codes:
00NNNNNN
Carrier Loss Alarm
01NNNNNN
Audio Loss Alarm
02NNNNNN
Phase Alarm
03NNNNNN
Over(load) Alarm
Channel Data:
MM000001
Channel 1
MM800000
Channel 24
B0 set represents Channel 1 Alarm
B1 set represents Channel 2 Alarm
B2 set represents Channel 3 Alarm
B22 set represents Channel 23 Alarm
B23 set represents Channel 24 Alarm
Where MM indicates 1 byte of Command code and NNNNNN indicates 3 bytes of channel data.
Examples:
ALARM unit reports that Channel
3
has just tripped into
Phase Alarm
. Unit sends out the following message:
02000004<cr><lf>
.
ALARM unit reports that Channel
23
has just tripped into
Overload Alarm.
Unit sends out the following message:
03400000<cr><lf>
.
4) Messages to ALARM unit
Data is sent to the ALARM unit using the same data format as in part 3, above. The initial command code the unit can accept is 80,
which is channel reset. Any number of channels may be reset using this one command:
Command Code:
80NNNNNN
Channel Reset
Channel Data:
80000001
Channel 1 Alarm Reset
80800000
Channel 24 Alarm Reset
80FFFFFF
All channels Alarm Reset
5) Notes
1)
Hexadecimal notation is indicated in this section.
2)
The ALARM units only generate and respond to RS232 commands when the
Option Select Switch
(
Item E
, page 14) is set
to
Normal Operation
(DIP section
3
).
3)
The ALARM unit will only generate messages when a check of state occurs with the unit, i.e.,
Acquisition
or
Loss of
and
Alarm
state.