MITEQ TECHNICAL NOTE 25T052
OCTOBER 2002
REV A
LOCAL/REMOTE CONTROL
DESCRIPTION
OUTDOOR-MOUNTED
TEST TRANSLATOR
WITH REMOTE CONTROL
______________________
1.0 INTRODUCTION
This document provides a description of the monitor and control functions provided with the
MITEQ Outdoor-Mounted Test Translator with Remote Control.
Among the features are optional control of LO frequency for multi-band units, control of output
attenuation, optional control of input attenuation and 32 memory locations for the unit, where
setups can be stored and recalled easily. Also, a log is continuously updated with time stamped
records of significant events such as status and setup changes for the unit. The internal
frequency reference can be adjusted via software so there is no need to open the unit.
2.0 MONITOR AND CONTROL ACCESS
Each unit is provided with both a local and a remote serial interface. Monitor and control of the
unit is performed through these ports. A robust command protocol set is available at both ports.
Status is always accessible at both ports. Control, however, is limited to one port at a time. The
unit can be placed under either local or remote control from the local port exclusively. To change
the control the proper command must be sent to the local port.
The unit defaults to remote control upon power-up. Also, while in Local mode, if thirty minutes of
inactivity at the local port expire, remote control is automatically restored.
Local control accommodates initial setup and maintenance of the system. The RS232 local
interface easily connects to a PC COM port. This prevents local operation from interrupting the
polling of a remote host computer. The baud rate and parity of the local port are permanently
fixed at 9600 and odd respectively.
Remote communication is provided via either an RS485 (2-wire) or an RS422 (4-wire) serial
interface to support a multi-drop bus arrangement. The remote interface parameters such as
address, baud rate and parity are set from the local port. The message format is identical for
both ports. All transmissions are multi-byte sequences beginning with a header byte and ending
with a trailer byte followed by a checksum byte. The transmitted bytes are all ASCII printable
characters in the range of 20H to 7EH.
MITEQ provides software for local setup and operation of the unit. This document outlines the
communication protocol information necessary for the development of remote monitor and
control applications. Some of the command sequences apply to only one of the ports.
3.0 LOCAL OPERATION
Upon Power-up the green power LED will be lit, and the unit will be in remote control mode.
During operation, the red alarm LED will light whenever a component fault exists.
The unit is supplied with an RS232 local interface port. Status is always available locally. The
unit can be placed under local control by sending the appropriate command to the local port only.
If the unit is under local control and the local port is inactive for more than thirty minutes, remote
control is automatically restored.
MITEQ provides local monitor and control software that can be run on an IBM compatible PC.
The local message format is identical to the remote format. Local communication is fixed at
9600 baud and odd parity. The remote address, baud rate, and parity are set from the local port
during initial setup. In order to maintain consistency with the remote message format, the
address byte must be included in local communications, however, it is ignored.
All messages to the unit are acknowledged with a response message. The unit continually
monitors the local communications bus and will acknowledge messages addressed to it. When
in Remote mode, receipt of any SET commands (commands beginning with “$”) at the local port
will be ignored and the unit will respond with an error code.
4.0 REMOTE OPERATION
The unit is supplied with an RS485 remote interface or, as an option, can be supplied with
RS422. The command structures for all of these serial buses are identical. Status is always
available at the remote port regardless of which port is in control. Remote or local control cannot
be selected from the remote port. This function is available at the local port only. If the unit is
inadvertently left in local control mode, after thirty-minutes of inactivity at the local port, remote
control will be automatically restored.
All messages addressed to the unit are acknowledged with a response message. The unit
continually monitors the remote communication bus and will accept commands, addressed to it,
even in Local mode. When in Local mode, receipt of any SET commands (commands
beginning with “$”) at the remote port will be ignored and the unit will respond with an error code.
2
5.0 LOCAL/REMOTE COMMUNICATIONS
5.1 LOCAL/REMOTE MESSAGE PROTOCOL (RS232/RS485/RS422)
The data format is a 10-bit sequence for each character. If odd or even parity is selected the ten
bits are 1 Start, 7 Data, 1 Parity, and 1 Stop bit. If the parity is set to none, the bits are 1 Start, 8
Data, and 1 Stop bit. The local address character must be included in all local messages but is
ignored. The local baud rate and parity are fixed at 9600 and odd respectively. The remote
Address, Baud Rate, and Parity are programmable from the local control port.
If any character in a command message contains an error in parity, framing, overrun, or the
checksum is incorrect, the command is ignored and no response is made. When odd or even
parity is selected, all characters, including the checksum character, are checked for parity. The
response time from command to acknowledge is 100 ms. maximum.
5.2 MESSAGE FORMAT
The message format is as follows:
HEADER - UNIT ADDRESS - COMMAND/ERROR CODE PARAMETERS - TRAILER - CHECKSUM
The response time from command to acknowledge is 100 ms. maximum. Since all bytes are
ASCII printable characters, a compatible terminal may be used to control the unit or monitor
traffic on the communication bus.
5.2.1 HEADER BYTE
The Header byte is 7BH, ASCII character "{".
5.2.2 UNIT ADDRESS
The unit may take on the address values from 64 to 95 (40H to 5FH).
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5.2.3 COMMAND CODE SUMMARY
COMMAND CODES
ASCII Character String
Function
REV
Firmware title and revision
CLK
Internal Calendar and Clock
TMP
Internal Thermometer reading
VLT
System Voltages
STA
Unit Status
ALR
Unit Alarm Status
FRQ
Unit LO Frequency
ATT
Unit Output Attenuation
ATI
Unit Input Attenuation
COM
Unit Combination Command
MUT
Unit Mute
MEM
Store/Recall Memory register
SET
Store/Recall Memory register and set unit
LOG
Unit LOG functions
REM
Remote/Local mode
BUS
Remote bus selection
SPD
Remote baud rate selection
PAR
Remote parity selection
ADR
Remote address selection
REF
Reference Frequency Adjust
FRS
Reference Frequency Source
NAM
Unit Name
4
5.2.4 ERROR CODES
ASCII Character
Function
a
Command not recognized
b
Illegal parameter or parameter out of range
c
Port does not have control rights
d
Busy
5.2.5 PARAMETERS
Parameters are all ASCII printable characters in the range of 20H to 7EH. Numeric parameters
are sent MSD first, LSD last. Values which do not adhere to the command format, or are
beyond the allowable range, will be rejected and cause the unit to respond with an error code.
5.2.6 TRAILER BYTE
The Trailer byte is 7DH, ASCII character "}".
5.2.7 CHECKSUM BYTE
The checksum byte is the sum modulo 95 of all message characters beginning with the header
byte up to and including the trailer byte. The value 32 is subtracted from each character value
before taking the modulo 95 sum. The value 32 is added to the final sum to obtain the checksum
value. All values are in decimal.
Checksum = MOD [(character value - 32), 95] + 32
Below is a program, written in the ‘C’ programming language that illustrates the checksum
calculation.
/*
return the checksum character for the message in array
subtract 32 from each character before taking modulo 95 sum
add 32 to the final sum
mes_len = message length
*/
char check_sum(char *array, char mes_len)
{
char i,sum;
for (i = 0, sum = 0; i < mes_len; i++) {
sum += *array++ - 32;
sum %= 95;
}
return(sum + 32);
}
5
5.3 COMMAND CODE DESCRIPTION
The following paragraphs describe each of the command codes. For clarity the header,
address, trailer and checksum characters are not shown. Upper case letters are the actual
command or response characters. Lower case letters represent parameter character strings.
Commands preceded by “?” are QUERY commands and those commands preceded by “$” are
SET commands. QUERY commands are used to examine system parameters while SET
commands are intended to modify system parameters.
Below is a detailed description of the protocol required for each of the commands and replies.
5.3.1 FIRMWARE TITLE AND REVISION = REV
There is no SET command.
The QUERY command requires no parameters.
Remote Command Sequence: ?REV
Unit Response: ?REV firmware title and revision
The length of this reply will vary depending on the title of the applicable firmware
5.3.2 INTERNAL CALENDAR AND CLOCK = CLK
The SET command requires a 12-character parameter, which sets the date and time of the
Internal Calendar and Clock.
Remote Command Sequence: $CLKyymmddhhnnss
Unit Response: $CLK
The QUERY command requires no parameters.
Remote Command Sequence: ?CLK
Unit Response: ?CLKyymmddhhnnss
yy: Year, 2 digit ASCII numeric characters, MSD first, LSD last.
mm: Month, 2 digit ASCII numeric characters
dd: Day, 2 digit ASCII numeric characters
hh: Hour, 2 digit ASCII numeric characters
nn: Minute, 2 digit ASCII numeric characters
ss: Second, 2 digit ASCII numeric characters
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5.3.3 INTERNAL THERMOMETER READING = TMP
There is no SET command.
The QUERY command requires no parameters.
Remote Command Sequence: ?TMP
Unit Response: ?TMPsttt
s: “+” or “-“ indicating sign.
ttt: Temperature in degrees Celsius, 3 digit ASCII numeric characters
5.3.4 SYSTEM VOLTAGES = VLT
There is no SET command.
The QUERY command requires a one-digit parameter indicating the voltage to be reported.
Remote Command Sequence: ?VLTx
Unit Response: ?VLTxsvv.vv
x: “a” through “p” indicating the particular voltage to be reported.
s: “+” or “-“ indicating sign.
vv.vv: Four-digit ASCII numeric characters, indicating the measured voltage in Volts.
a:
b:
c:
d:
e:
f:
g:
h:
+24.00 Volt Supply Rail
+20.00 Volt Supply Rail
+5.00 A Volt Supply Rail
+5.00 B Volt Supply Rail
-15.00 Volt Supply Rail*
N/A
N/A
N/A
i: N/A
j: N/A
k: N/A
l: Downconverter RF Phase Voltage
m: N/A
n: N/A
o: N/A
p: Auxiliary Voltage
*(If applicable)
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5.3.5 UNIT STATUS = STA
There is no SET command.
The QUERY command requires no parameters.
Remote Command Sequence: ?STA
Unit Response: ?STAFffffffffTttt(Aaaa)LlIiMm?abcdefghij
F: LO Frequency indicator.
fffffff: Eight-digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the frequency in kHz.
T: Output Attenuation indicator.
ttt: Three-digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the attenuation in tenths of a dB.
A: Input Attenuation indicator. Included only on units with input attenuators
aaa: Three-digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the attenuation in tenths of a dB.
L: Local / Remote mode indicator.
l: "0" or "1" ASCII numeric character
0 = Local control
1 = Remote control
I: IF indicator.
i: "0" ASCII numeric character
M: Mute status indicator.
m: "0" or "1" ASCII numeric character
0 = not mute
1 = mute.
?: Component Fault Status indicator
a-j: "0" or "1" ASCII numeric character
0 = No fault
1 = Fault
a-j indicates the status of the component faults described below.
5.3.6 SYSTEM FAULT STATUS = ALR
The SET command requires ten parameters of which the first eight and tenth are ignored. The
ninth parameter is used to set/clear a user generated test alarm.
Remote Command Sequence: $ALRabcdefghij
Unit Response: $ALR
8
The QUERY command requires no parameters.
Remote Command Sequence: ?ALR
Unit Response: ?ALRabcdefghij
?: Component Fault Status indicator
a-j: "0" or "1" ASCII numeric character
0 = No fault
1 = Fault
a-j indicates the status of the component faults described below.
a Power Supply Alarm
b Synthesized Local Oscillator Lock Alarm
c N/A
d N/A
e N/A
f N/A
g N/A
h N/A
i User Test Alarm
j Logged Alarm
5.3.7 UNIT LO FREQUENCY = FRQ
The SET command requires one parameter which can be seven or eight digits in length
representing the frequency in kHz. A leading zero may be used with frequencies below 10 GHz.
If no alarms exist, this command also unmutes the output.
Remote Command Sequence: $FRQfffffff(f)
Unit Response: $FRQ
The QUERY command requires no parameters. The reply will consist of eight digits indicating
the frequency in kHz. A leading zero will be used for frequencies less than 10 GHz.
Remote Command Sequence: ?FRQ
Unit Response: ?FRQffffffff
FRQ: LO Frequency indicator
fffffff(f): Seven or Eight-digit ASCII numeric characters,
MSD transmitted first, LSD last indicating
frequency in kHz.
5.3.8 UNIT OUTPUT ATTENUATION = ATT
The SET command requires a three-digit parameter representing the attenuation in dB. The
three-character string “INC” or “DEC” can be used in place of the attenuation parameter to
increment or decrement the attenuator by 0.2 dB. This event is logged in unit event log.
Remote Command Sequence: $ATTttt or
$ATTINC or
$ATTDEC
Unit Response: $ATT
9
The QUERY command requires no parameters.
Remote Command Sequence: ?ATT
Unit Response: ?ATTttt
ATT: Output Attenuation indicator
ttt: Three-digit parameter indicating attenuation in
tenths of a dB.
INC: Used in place of “ttt” in the SET command to
increment the attenuator 0.2 dB
DEC: Used in place of “ttt” in the SET command to
decrement the attenuator 0.2 dB
5.3.9 UNIT INPUT ATTENUATION = ATI (this command is only valid for units equipped with
the optional Input attenuator)
The SET command requires a three-digit parameter representing the attenuation in dB. The
three-character string “INC” or “DEC” can be used in place of the attenuation parameter to
increment or decrement the attenuator by 0.2 dB. This event is logged in unit event log.
Remote Command Sequence: $ATIttt or
$ATIINC or
$ATIDEC
Unit Response: $ATI
The QUERY command requires no parameters.
Remote Command Sequence: ?ATI
Unit Response: ?ATIttt
ATI: Input Attenuation indicator
ttt: Three-digit parameter indicating attenuation in
tenths of a dB.
INC: Used in place of “ttt” in the SET command to
increment the attenuator 0.2 dB
DEC: Used in place of “ttt” in the SET command to
decrement the attenuator 0.2 dB
5.3.10 UNIT COMBINATION COMMAND = COM
The SET command requires three parameters; an LO frequency parameter, an output
attenuation parameter, and an input attenuation parameter.
Remote Command Sequence: $COMFfffffff(f)Tttt(Aaaa)
Unit Response: $COM
The QUERY command requires no parameters.
Remote Command Sequence: ?COM
Unit Response: ?COMFffffffffTtttAaaa
F: LO Frequency indicator.
Ffffff(f): Seven or Eight digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the frequency in kHz.
10
T: Output Attenuation indicator.
ttt: Three digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the attenuation in tenths of a dB.
A: Input Attenuation indicator. Included only on units with input attenuators
aaa: Three digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the attenuation in tenths of a dB.
5.3.11 UNIT MUTE COMMAND = MUT
The SET command requires a one-digit parameter indicating mute or unmute.
Remote Command Sequence: $MUTm
Unit Response: $MUT
The QUERY command requires no parameters.
Remote Command Sequence: ?MUT
Unit Response: ?MUTm
MUT: Mute indicator.
5.3.12 UNIT MEMORY REGISTER STORE/RECALL = MEM
The SET command stores LO frequency, output attenuation and input attenuation into a selected
memory register. Thus four parameters are required; memory register, LO frequency, output
attenuation and input attenuation. This command does not affect unit operation.
Remote Command Sequence: $MEMnnFfffffff(f)Tttt(Aaaa)
Unit Response: $MEM
The QUERY command requires one parameter indicating the memory register to recall and
returns the contents of that register. This command does not affect unit operation.
Remote Command Sequence: ?MEMnn
Unit Response: ?MEMnnFfffffff(f)Tttt(Aaaa)Ii
nn: Two digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the memory register accessed.
F: LO Frequency indicator.
Ffffff(f): Seven or Eight digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the frequency in kHz.
T: Output Attenuation indicator.
ttt: Three digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the attenuation in tenths of a dB.
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A: Input Attenuation indicator. Included only on units with input attenuators
aaa: Three digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the attenuation in tenths of a dB.
5.3.13 UNIT MEMORY REGISTER STORE/RECALL AND SET = SET
The SET command stores LO frequency, output attenuation and input attenuation into a selected
memory register. Thus four parameters are required; memory register, LO frequency, output
attenuation and input attenuation. The unit is set to the parameters included in the command.
Remote Command Sequence: $SETnnFfffffff(f)Tttt(Aaaa)
Unit Response: $SET
The QUERY command requires one parameter indicating the memory register to recall and
returns the contents of that register. The unit is set to the parameters included in the reply.
Remote Command Sequence: ?SETnn
Unit Response: ?SETnnFfffffff(f)Tttt(Aaaa)Ii
nn: Two digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the memory register accessed.
F: LO Frequency indicator.
fffffff: Seven or Eight digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the frequency in kHz.
T: Output Attenuation indicator.
ttt: Three digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the attenuation in tenths of a dB.
A: Input Attenuation indicator. Included only on units with input attenuators
aaa: Three digit ASCII numeric characters,
MSD transmitted first, LSD last.
Indicating the attenuation in tenths of a dB.
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5.3.14 UNIT EVENT LOG = LOG
The only SET command clears the unit log of its contents.
Remote Command Sequence: $LOG00
Unit Response: $LOG
The QUERY command requires a two-digit parameter indicating the log entry to be examined. If
entry 00 is selected, the unit returns the number of log entries currently in the log, otherwise the
unit responds with the date, time and a code indicating the event which has occurred.
Remote Command Sequence: ?LOGnn
Unit Response: ?LOGnnCyymmddhhnnssEee
nn: Two digit ASCII numeric characters, MSD transmitted first, LSD last. Indicating the
log entry queried.
C: Calendar/Clock indicator
yy: Year, two digit ASCII numeric characters, MSD transmitted first, LSD last.
mm: Month, 2 digit ASCII numeric characters
dd: Day, 2 digit ASCII numeric characters
hh: Hour, 2 digit ASCII numeric characters
nn: Minute, 2 digit ASCII numeric characters
ss: Second, 2 digit ASCII numeric characters
E: Event indicator.
cc: Event Code 01 to 99 represent the following:
01:
02:
04:
06:
08:
10:
14:
16:
26:
29:
31:
33:
Processor Startup
+24V Power Supply Fault
+15V Power Supply Fault
+5V A Power Supply Fault
+5V B Power Supply Fault
-15V Power Supply Fault
Synthesizer Lock Fault
Synthesizer Level Fault
LO Frequency Change
Unit Mute By Operator
Test Alarm Activated By Operator
Unit Name Change
03:
05:
07:
09:
11:
15:
17:
27:
30:
32:
34:
+24V Power Supply Fault Recovery
+15V Power Supply Fault Recovery
+5V A Power Supply Fault Recovery
+5V B Power Supply Fault Recovery
-15V Power Supply Fault Recovery
Synthesizer Lock Fault Recovery
Synthesizer Level Fault Recovery
Output Attenuation Change
Unit Unmute By Operator
Test Alarm Deactivated By Operator
Input Attenuation Change
13
5.3.15 UNIT REMOTE/LOCAL CONTROL MODE = REM
The SET command applies to the local port only. It requires a one-digit parameter indicating
remote or local control. If the unit is in local mode and the local control port is idle for more than
thirty minutes the unit will automatically switch into remote control mode.
Remote Command Sequence: $REMr
Unit Response: $REM
The QUERY command requires no parameters and is available from both ports.
Remote Command Sequence: ?REM
Unit Response: ?REMr
r: "0" or "1" ASCII numeric character
0 = Local control mode
1 = Remote control mode
5.3.16 REMOTE CONTROL BUS SELECTION = BUS
The SET command requires a one-digit parameter indicating the remote bus selection. This
command is available from the local port only.
Remote Command Sequence: $BUSb
Unit Response: $BUS
The QUERY command requires no parameters.
Remote Command Sequence: ?BUS
Unit Response: ?BUSb
b: "0" or "1" ASCII numeric character
0 = RS485 (two-wire, half duplex)
1 = RS422 (four-wire, full duplex)
5.3.17 REMOTE PORT BAUD RATE SELECTION = SPD
The SET command requires a one-digit parameter indicating the remote baud rate. This
command is available from the local port only.
Remote Command Sequence: $SPDb
Unit Response: $SPD
The QUERY command requires no parameters.
Remote Command Sequence: ?SPD
Unit Response: ?SPDb
b: "0" through "6" ASCII numeric character
0 = 300
4 = 4800
1 = 600
5 = 9600
2 = 1200
6 = 19200
3 = 2400
14
5.3.18 REMOTE PARITY SELECTION = PAR
The SET command requires a one-digit parameter indicating the remote parity. This command
is available from the local port only.
Remote Command Sequence: $PARp
Unit Response: $PAR
The QUERY command requires no parameters.
Remote Command Sequence: ?PAR
Unit Response: ?PARp
b: "0" through "6" ASCII numeric character
0 = Odd
1 = Even
2 = None
5.3.19 REMOTE ADDRESS SELECTION = ADR
The SET command requires a two-digit parameter indicating the remote bus address in decimal.
This command is available from the local port only.
Remote Command Sequence: $ADRaa
Unit Response: $ADR
The QUERY command requires no parameters.
Remote Command Sequence: ?ADR
Unit Response: ?ADRaa
aa: "64" through "95" ASCII numeric characters indicating address.
5.3.20 REFERENCE FREQUENCY ADJUSTMENT = REF
The SET command requires a four-digit parameter indicating the twelve-bit reference frequency
adjustment from 0 to 4095.
Remote Command Sequence: $REFaaaa
Unit Response: $REF
The QUERY command requires no parameters.
Remote Command Sequence: ?REF
Unit Response: ?REFaaaa
aaaa: Reference frequency adjustment (0000 to 4095) in
ASCII numeric characters.
15
5.3.21 REFERENCE FREQUENCY SOURCE = FRS
There is no SET command.
The QUERY command requires no parameters.
Remote Command Sequence: ?FRS
Unit Response: ?FRSn
n: "0" or "1" ASCII numeric character
0 = Internal Reference
1 = External Reference
5.3.22 UNIT NAME = NAM
The SET command requires an ASCII string from one to seventy-two digits in length indicating
the name of the unit. Allowable characters are in the range of 20H to 7AH.
Remote Command Sequence: $NAMnnnnnnnnnn...
Unit Response: $NAM
The QUERY command requires no parameters.
Remote Command Sequence: ?NAM
Unit Response: ?NAMnnnnnnnnnn...
nnnnnnnnnn...: Seventy-two character unit name.
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6.0 INTERFACE CONNECTIONS
6.0.1 AC POWER CONNECTIONS
J5-Pin Signal
1
2
3
4
AC HOT
AC NUETRAL
CHASSIS GROUND
NO CONNECTION
6.0.2 RS422/485 REMOTE INTERFACE AND SUMMARY ALARM CONNECTIONS
J3-Pin Signal
A
E
J
K
Data Out –
Data In Data Out +
Data In +
(Internally connected to J7-E)
(Internally connected to J7-C)
(Internally connected to J7-D)
(Internally connected to J7-B)
B
C
D
DOWNCONVERTER SUMMARY ALARM NORMALLY CLOSED
DOWNCONVERTER SUMMARY ALARM COMMON
DOWNCONVERTER SUMMARY ALARM NORMALLY OPEN
For RS485 two-wire party line operation Data In + must be connected to Data Out +, and Data
In - must be connected to Data Out -. These can be connected using the internal control board
jumpers J6C and J6D or wired externally.
To simplify multi-drop wiring, the RS485 / RS422 remote interface pins called out on J3 are
internally connected to the pins called out on J7.
Form C contacts are provided to indicate the operational status of each converter.
Status:
Normal:
Fault:
J3-B to J3-C closed, J3-D to J3-C open.
J3-B to J3-C open, J3-D to J3-C closed.
6.0.3 RS232 LOCAL INTERFACE CONNECTIONS
J5-Pin Signal
A
B
C
D
E
F
Chassis Ground
RD
TD
CTS
RTS
No Connection
CTS and RTS are connected together with an internal control board jumper J6E. This jumper
can be removed to use the RTS / CTS handshaking.
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