Service Manual

5-12 Model 340 Telemetry System Revision A
2006920-001
Calibration: Transmitter Calibration
Transmitter Calibration
UA Channel
1. Connect the positive lead of a 0–4 V adjustable DC lab supply to J5
pin 1 (PRESS+) through a 100 KΩ resistor and the negative lead to
J5 pin 2 (PRESS–) and J5 pin 6 (GROUND). Jumper a 100 Ω resistor
across J5 pin 1 and J5 pin 2. Add a jumper between J5 pin 12 and J5
pin 7. Preset R197 fully counter-clockwise (maximum resistance),
and R196 to approximately the mid-adjustment point.
2. Connect a digital voltmeter to TP18. Adjust the DC lab supply for a
voltage at TP18 of 0 V ± 10 mV. Connect the frequency counter to
TP19 and preset R196 for a frequency of approximately 1.75 kHz.
Adjust the lab supply for a voltage of –4.000 Vdc ± 10 mV at TP18.
Adjust R197 for a frequency of approximately 1.5 kHz. Swap the
leads from the lab supply to J5 and adjust the supply for a voltage of
+4.000 V ± 10 mV at TP18. Readjust R196 for a frequency of
approximately 2.0 kHz. Repeat the above procedure until TP19
produces a frequency of 2.000 kHz ± 5 Hz with TP18 at +4.000 V ± 10
mV and a frequency of 1.500 kHz ± 5 Hz with TP18 at –4.000 V ± 10
mV.
ECG Channel
1. Connect a digital voltmeter to TP6. Connect the frequency counter to
TP20 and preset R193 for a frequency of approximately 2.7 kHz.
Connect the positive output of the 0–4V DC lab supply to connector
J3 pin 1 and the negative output of the supply to J3 pin 2. Add a
jumper between J6 pin 2 and J6 pin 3. Adjust the lab supply for a
voltage of –4.000 Vdc ± 10 mV at TP6. Adjust R194 for a frequency of
approximately 2.45 kHz.
2. Swap the input leads from the lab supply to J3 and adjust the supply
for a voltage of +4.000 V ± 10 mV at TP6. Readjust R193 for a
frequency of approximately 2.95 kHz. Repeat the above procedure
until TP20 produces a frequency of 2.950 kHz ± 5 Hz with TP6 at
+4.000 V ± 10 mV and a frequency of 2.450 kHz ± 5 Hz with TP6 at
–4.000 V ± 10 mV.