Innomed Medical
Heart Screen 60G-80G-L
Service manual
2014.01.09 28/84
D-5450-1-B_HS60G80GL_SM_ENG.doc
6.5.7 Checking pacemaker detector
Warning ! With PACE generator measurements the system noise can be max. 0.5 mm!
Apply (2000 +/-0.5%
R
Vpp/10 Hz sine) + PACE signal on the amplifier input according to the tables from a ground-
independent generator. PACE impulse amplitude should be 2mVpp, width 0.5ms, repeating
frequency 1Hz.
Set the device to half sensitivity (x1/2) and 25 mm/sec speed.
Connect the patient cable according to the following tables, start the individual channels with the channel selector and
measure the signal amplitude. Only the measurement order quality has to be checked on the monitor, meaning that the
PACE impulse must appear on the 2mV amplitude sine signal. The PACE detector operation must be checked with the
oscilloscope connected to the text connection’s PACE output.
Active TTL level impulses must be seen at low level on the oscilloscope, which width is 100 (+/-20 %) ms and appear
with the PACE repeating frequency. The impulse widths can be set with R10 (if necessary, can be changed to 510K or
1M may be enough in parallel).
The PACE detector operation must be checked on all leads with both positive and negative PACE polarity. If the
detector does not signal, the R90-94 or R88-95 resistance pairs can be used to slightly set the comparison level. If
more serious modification is required, the level may be decreased with resistors, for example 47K, connected in
parallel with R11-12-44-47-61-68-69-70 according to the channels.
P1 P2
Measured
lead
Positive
impulse pass
Negative
impulse pass
L
all other
I
R
all other
II
V1 all
other V1
V2 all
other V2
V3 all
other V3
V4 all
other V4
V5 all
other V5
V6 all
other V6
6.5.8 Checking PACE tolerance
Connect only the PACE impulse generator to the amplifier’s input according to the table. PACE impulse amplitude
should be 700mVpp, width 2ms, repeating frequency 1Hz.
Set the device to the highest, 0,5mV/cm sensitivity (x2) and 5 mm/sec speed.
Connect the patient cable according to the following table and start monitoring the individual channels one-by-one,
and then block the amplifier until the PACE signal arrives. On the monitor check the baseline shift due to the PACE
impulse. 12ms after the PACE the baseline can shift max. 100
R
V compared to before the PACE. The baseline’s long-
term stability can be 6mm/30 sec (300
R
V/30sec).