Hameg Instruments HM8122 Manuel page 26

Internal Test Programs
At power up the internal test program checks all functions
of the counter. When the tests are completed satisfactorily,
the counter sets the display to zero and selects the default
measuring function. If an error is detected, it is indicated
by an "E" followed by the test number that failed.
E 1 microprocessor RAM error
E 2 program ROM error
E 3 counting chain error
E 4 attempt to calibrate the counter while a signal is
connected to the external reference input.
E 5 attempt to set an invalid NPR number (RPM function)
Options
Specifications HO85
The optional HO85 is a high stability ovenized crystal
oscillator to fit into the HM8122 universal counter. The
option is field installable by simple changing the oscillator
unit. Subsequently the counter has to be recalibrated.
The high frequency stability of the HO85 is obtained by
means of a temperature controlled "crystal oven". The
temperature stability is approx. 0.1°C in the entire working
temperature range from +10°C to +60°C. Thus the high
–8
stability of 5x10 per day is achieved. The specified
accuracy is obtained after a warm-up of 15 min.
Specifications: (after 48 hours of continuous operation)
Frequency stability:
Ambient temperature: +10°C to +60°C (working)
Frequency repitition accuracy
after 24 hours of "power off": ±5x10
The interfaces HO88/HO89
The test instruments of the HAMEG series HM8100 have
all been designed to permit their use in automated testing
environments. In order to connect them, either the interface
HO88 (IEEE-488) or HO89 (RS232C) option is required.
Series HM8100 instruments equipped with the IEEE-488
bus interface comply with the stipulations of the IEC-625-
1 and IEEE-488 standards.
If the HO88/HO89 interface is ordered together with the
HM8122 counter, it is installed whithin it at the factory.
The interfaces are also available as a separate option for
retrofitting purposes at a later time.
Installation of HO88/89
To install the interface see HO88 or HO89 manual.
Connect CON1/HO88-89 to CN604/HM8122 and CON3/
HO88-89 to CN606/HM8122.
26 HM8122
–8
± 5x10 per day
±1.5x10 –7 per month
± 1x10 –6 per year
–55°C to +90°C (storage)
–8
Command Codes HO88
Device-dependent messages that are understood by the
HM8122:
("*" indicates a default setting, i.e. corresponding the
state of the HM8122 when initialized or when the command
"CLR" is received. "XXXXX" represents a positive integer
with between 1 and 5 digits.)
Functions
FRC : Measure frequency on channel C
TOT : Totalize events on channel A
PRA : Measure period on channel A
FRA* : Measure frequency on channel A
FRB : Measure frequency on channel B
RAB : Calculate frequency ratio of channel A
to channel B
TIA : Measure average time interval A-B
TI1 : Measure time interval A-B
(single measurement)
RPM : Measure revolutions per minute (channel A)
Measurement control
SMTXXXXX : Set measurement time to XXXXX ms
TRG : Trigger new measurement
XAR : Select external arming mode
XGT : Select external gate mode
XC* : No external control
DH1 : Select display hold mode
DH : Reset display hold (auto measurements)
WT1* : Select wait time between measurements
WT : No wait time between measurements
STR : Start TOTALIZE function (TOT)
STP : Stop TOTALIZE function
NPCXXXXX : Set no. of pulses per rev. to XXXXX
(RPM function)
OF1 : Select OFFSET mode
OF : Reset OFFSET mode
Display control
RES : Display Reset
REF : Recall and display reference value
in offset mode
DT1 : Display measurement time
DT* : Reset measurement time display function
DS1* : Select DISPLAY ON
DS : Select DISPLAY OFF
DN1 : Display NPR value in RPM mode
DN : Reset display NPR value
Bus and output control
SR1 : Set service request ON
SR : Set service request OFF
CLR : Clear (initialize to default settings)
CNF : Poll counter settings (configuration)
NOP* : Set output mode to NORMAL
COP : Set output mode to COMPRESSED
RM : Reset to local mode
LK1 : Local lock out active
LK0 : Local lockout desactive
ID? : Device identification
Subject to change without notice