Hameg Instruments HM5530 Manuel page 37

Test signal:
#tl(E) = Test signal level "TL-xxx.x" (in dB-Unit)
#tg(E) = Test signal gen. ON/OFF "TGx"
(x=0:TG OFF, x=1:TG ON)
Filter:
#bw(E) = Resolution bandwidth "BWxxxx" (in kHz)
#ba(E) = Bandwidth automatic "BAx"
(x=0: Manual; x=1: Auto)
#vf(E) = Video fi lter "VFx" (x=0:VF OFF, x=1:VF ON)
#kl(E) = Remote "KLx" (x=0:Local, x=1:Remote)
Signal:
#vm(E) = Video mode "VMx" (x=0:A,x=1:B,x=2:A-B)
General:
#vn(E) = Version nummer "VNx.xx" (x.xx = 1.00 ... 9.99)
#hm(E) = Device typ "HMxxxx"(xxxx = 5530)
st
1 Example: „#uc(E) (uncalibrated)": PC sends #uc(CR).
Instrument answers: UC0(CR) (calibrated) or
UC1(CR) (uncalibrated)
nd
2 Example: „#vn(E)", PC requests number of version:
PC sends #vn(CR). Instrument answers:
x.xx(CR) x.xx z. B.: 1.23
rd
3 Example: „#hm(E)", pc requests type of instrument:
PC sends #hm(CR).
Instrument answers: 5530 (CR)
th
4 Example: PC sends a sequence of commands to
the analyzer:
#kl1(E) = Switches to remote control.
#cf0752.000(E) = Sets center frequency to 752 MHz
#sp0002.000(E) = Sets span to 2 MHz
#bw120(E) = Sets resolution abdnwidth to 120 kHz
#kl0(E) = Returns control to front panel.
If a command is not recognized, the instrument will not respond with a
message to the pc (no RD (CR) or no parameter transmission.
Extensive description of the command #bm1
#BM1(CR) = Block mode (transmits 2048 data bytes
via the RS-232 interface)
The transmission data consist of 2048 bytes: trans_byte [0] to trans_byte
[2047]. These 2048 data bytes contain 2001 signal bytes, the parameter
center frequency and a checksum of the signal bytes.
The signal data are on the following transmission bytes:
trans_byte[n] = sig_data[n] ( n = 0 bis n = 2000):
trans_byte[0] = sig_data[0]
trans_byte [2000] = sig_data[2000]
The checksum is a 24 bit word (= 3 bytes ), it consists of: checksum =
sig_data[0] + sig_data[1] +.. sig_data[1999] + sig_data[2000] (=sum of
all signal data)
The 24 bit checksum is on the following data bytes:
trans_byte[2044] = 1st byte checksum [MSB]
trans_byte[2045] = 2nd byte checksum
trans_byte[2046] = 3rd byte checksum [LSB]
The center frequency parameter is on the following transmission data
bytes:
trans_byte [2016] = 'C'; trans_byte [2017] = 'F'; trans_byte [2018] = 'x';
I n t e r f a c e , R e a d i n g m e a s u r e m e n t r e s u l t s , r e m o t e c o n t r o l
trans_byte [2019] = 'x'; trans_byte [2020] = 'x'; trans_byte [2021] = 'x';
trans_byte [2022] = '.'; trans_byte [2023] = 'x'; trans_byte [2024] = 'x';
trans_byte [2025] = 'x'; (x= '0' to '9') Example: CF0623.450
(These bytes are not used when calculating the checksum.)
The last character is always a CR (carriage return).
trans_byte[2047] = 0D hex (carriage return)
All other „free" bytes will be set to (00 hex).
Signal data and CRT display:
The signal data are the result of 2001 a/d conversions during a
sweep.
X position: The fi rst byte „sig_data(0)" corresponds to the fi rst point
on the screen, coinciding with the left edge of the graticule. All other
bytes follow linearly up to „sig_data(2000), this point coincides with the
right edge of the graticule. The frequency of the individual points can
be calculated from the center frequency and the span:
Frequency (x) = (center frequency – 0.5 span) + span x x/2000.
X = 0 ... 2000 (position of the point = sig_data(x)).
Y position: The 8 bit value (hex: 00 to FF) of each memory location of
sig_data(x) relates to the video signal as follows:1C hex (28 dec) coin-
cides with the bottom line of the graticule.
E5 hex (229 dec) coincides with the top line of the graticule (= reference
level)
The resolution in Y direction is 25 points per division (equals 10 dB at
10 dB/div).
The vertical distance of the points is 0.4 dB at 10 dB/div. or 0.2 dB at
5 dB/div.
The level of a specifi c point (y) can be calculated as follows:
For y ≤ 229 (Ref level position):
Level in dBm (y) = ref level (dBm) – ((229-y) x 0.4 dB) at
10dB/Div
For y 229 (Ref level position):
>
Level in dBm (y) = ref level (dBm) + ((y-229) x 0.4 dB) at
10dB/Div.
37
Subject to change without notice