DM501: Difference between revisions

Latest revision as of 07:48, 11 January 2024

Tektronix DM501
4½ digit multimeter Tektronix DM501 Produced from 1972 to 1980 Manuals Tektronix DM501 Manual (All manuals in PDF format unless noted otherwise)

Manuals – Specifications – Links – Pictures

The Tektronix DM501 is a 4½ digit multimeter plug-in for the TM500 system.

(See DM501A for the significantly different successor model.)

It also has a temperature input, requiring the P6058 temperature probe with a 4-pin LEMO S-series connector. The manual states that certain NPN transistors such as a 2N2484 may be used as temperature sensors in place of the probe with little or no selection of the transistor.

The DM501 MOD718D variant replaced the temperature range with a 200 mV input range providing 10 μV resolution (see Physical Measurements Handbook).

Key Specifications

DC Voltage	2 V_DC to 200 V_DC in decade ranges (0.1% + 0.01% FS), 1000 V_DC (0.1% + 0.02% FS); Input resistance 10 MΩ, CMRR >100 dB at DC, 80 dB at 60 Hz (1 kΩ unbal.), NMRR ≥30 dB at 60 Hz + 20 dB/decade
AC Voltage	2 V_DC to 200 V_AC in decade ranges, and 500 V_AC (0.7% + 0.01% FS for sine inputs only); Input impedance 10 MΩ // ≤70 pF, CMRR unspecified
DC Current	2 mA to 2 A in decade ranges, 0.2% + 0.05% FS
AC Current	2 mA to 2 A in decade ranges, 0.6% + 0.05% FS (for 40 Hz to 1 kHz sine)
Ohms	2 kΩ to 20 MΩ in decade ranges, current 1 mA to 0.1 μA respectively; 0.3% (20 MΩ: 0.5%) + 0.01% FS
Temperature	–55°C to +125°C (±1.5°C), +125°C to 150°C (±2.5°C)

Options

Option 1: Ordering without P6058 Temp Probe
Option 2: Without Temp Capability and Probe (visible by no Temp Out at the Front)

Links

Tektronix DM501 Check in and Calibration by Zenwizard Studios @ YouTube

Documents Referencing DM501

Document	Class	Title	Authors	Year	Links
Tekscope 1974 V6 N3.pdf	Article	The 31/53 Calculator-based Measurement Instrumentation Package	John Mulvey	1974	31 • 153 • DM501 • DC503
070-2088-00.pdf	Book	TM500 Series Rear Interface Data Book		1975	AF501 • AM501 • AM502 • DC501 • DC502 • DC503 • DC504 • DC505 • DC505A • DM501 • DM502 • FG501 • FG502 • FG503 • MR501 • PG501 • PG502 • PG505 • PG506 • PG508 • PS501 • PS502 • PS503 • PS503A • PS505 • RG501 • SC501 • SC502 • SG502 • SG503 • TG501
070-2088-01.pdf	Book	TM500 Series Rear Interface Data Book		1976	AF501 • AM501 • AM502 • AM511 • DC501 • DC502 • DC503 • DC504 • DC505 • DC505A • DD501 • DM501 • DM502 • FG501 • FG502 • FG503 • FG504 • LA501 • MR501 • PG501 • PG502 • PG505 • PG506 • PG508 • PS501 • PS502 • PS503 • PS503A • PS505 • RG501 • SC501 • SC502 • SG502 • SG503 • SG504 • SW503 • TG501 • TR501 • TR502

Rear interface

The DM501 has a rear input, selectable by a front-panel button, on B28 (Hi) / A29 (Lo), and digit-serial BCD outputs (TTL), see below. The manual does not specify a limit to the input voltage on the rear interface but since this uses card-edge pins adjacent to logic output pins, sticking to the the DM501A specification (200 V peak / 100 V RMS) appears prudent.

Internals

The DM501 is precise to 4½ digits, but not accurate to 4½ digits. The combination of an ADC built from opamps and discretes combined with a noisy high-frequency isolated power supply make for barely achievable 3½ digit accuracy over all ranges. Every TM500 DVM after the 501 (including the DM501A, the DM502, and so on) used integrated A-to-D converters and a mains-frequency isolated power supply.

Pictures

DM501
DM501 open left side
DM501 integrator board
DM501 integrator board solder side
DM501 rear interface

Components

Some Parts Used in the DM501

Part	Part Number(s)	Class	Description	Used in
307-1015-00	307-1015-00	Discrete component	resistor network	DM501
Fairchild 3814	156-0306-00	Monolithic integrated circuit	4½ digit dual-slope DVM controller	7A13 • 7L13 • 7L18 • DM501

@@ Line 5: / Line 5: @@
 (See [[DM501A]] for the significantly different successor model.)
-It also has a temperature input, requiring the [[P6058]] temperature probe with a 4-pin [[LEMO S-series connector]].
+It also has a temperature input, requiring the [[P6058]] temperature probe with a 4-pin [[LEMO S-series connector]].  The manual states that ''certain NPN transistors such as a 2N2484 may be used as temperature sensors in place of the probe with little or no selection of the transistor''.
 The '''DM501 MOD718D''' variant replaced the temperature range with a 200 mV input range providing 10 μV resolution (see [[Media:Physical Measurements Handbook.pdf | Physical Measurements Handbook]]).
 {{BeginSpecs}}
-{{Spec | DC Voltage | 2 V<sub>DC</sub> to 200 V<sub>DC</sub> in decade ranges (0.1% + 0.01% FS), 1000 V<sub>DC</sub> (0.1% + 0.02% FS) }}
+{{Spec | DC Voltage | 2 V<sub>DC</sub> to 200 V<sub>DC</sub> in decade ranges (0.1% + 0.01% FS), 1000 V<sub>DC</sub> (0.1% + 0.02% FS); Input resistance 10 MΩ, CMRR >100 dB at DC, 80 dB at 60 Hz (1 kΩ unbal.), NMRR ≥30 dB at 60 Hz + 20 dB/decade }}
-{{Spec | DC Voltage characteristics        | Input resistance 10 MΩ, CMRR >100 dB at DC, 80 dB at 60 Hz (1 kΩ unbal.), NMRR ≥30 dB at 60 Hz + 20 dB/decade }}
+{{Spec | AC Voltage | 2 V<sub>DC</sub> to 200 V<sub>AC</sub> in decade ranges, and 500 V<sub>AC</sub> (0.7% + 0.01% FS for sine inputs only); Input impedance 10 MΩ // ≤70 pF, CMRR unspecified }}
-{{Spec | AC Voltage | 2 V<sub>DC</sub> to 200 V<sub>AC</sub> in decade ranges, and 500 V<sub>AC</sub> (0.7% + 0.01% FS for sine inputs only) }}
-{{Spec | AC Voltage characteristics        | Input impedance 10 MΩ // ≤70 pF, CMRR unspecified }}
 {{Spec | DC Current | 2 mA to 2 A in decade ranges, 0.2% + 0.05% FS }}
 {{Spec | AC Current | 2 mA to 2 A in decade ranges, 0.6% + 0.05% FS (for 40 Hz to 1 kHz sine) }}
@@ Line 20: / Line 18: @@
 {{EndSpecs}}
-==Options==
+===Options===
 * Option 1: Ordering without P6058 Temp Probe
 * Option 2: Without Temp Capability and Probe (visible by no ''Temp Out'' at the Front)
+==Links==
+* [https://www.youtube.com/watch?v=GaSy1MezeNs                                  Tektronix DM501 Check in and Calibration] by Zenwizard Studios @ YouTube
+{{Documents|Link=DM501}}
+==Rear interface==
+The DM501 has a rear input, selectable by a front-panel button, on B28 (Hi) / A29 (Lo), and digit-serial BCD outputs (TTL), see below.
+The manual does not specify a limit to the input voltage on the rear interface but since this uses card-edge pins adjacent to logic output pins, sticking to the the DM501A specification (200 V peak / 100 V RMS) appears prudent.
 ==Internals==
-The DM501 is precise to 4½ digits, but not accurate to 4½ digits. The combination of a D-to-A converter built from opamps and discretes combined with a noisy high-frequency isolated power supply make for barely achievable 3½ digit accuracy over all ranges. Every TM500 DVM after the 501 (including the [[DM501A]], the [[DM502]], and so on) used integrated A-to-D converters and a mains-frequency isolated power supply.
+The DM501 is precise to 4½ digits, but not accurate to 4½ digits. The combination of an ADC built from opamps and discretes combined with a noisy high-frequency isolated power supply make for barely achievable 3½ digit accuracy over all ranges. Every TM500 DVM after the 501 (including the [[DM501A]], the [[DM502]], and so on) used integrated A-to-D converters and a mains-frequency isolated power supply.
 ==Pictures==
@@ Line 34: / Line 41: @@
 Tek_DM501_integrator_pcb-comp_side.jpg|DM501 integrator board
 Tek_DM501_integrator_pcb-solder_side.jpg|DM501 integrator board solder side
+DM501 rear interface.png | DM501 rear interface
 </gallery>
-==See also==
+==Components==
-* [[Media:Siliconix_LD120_and_LD121A_datasheets.pdf|Siliconix LD120 and LD121A datasheets]]
+{{Parts|DM501}}
-* [[Fairchild 3814]] counter IC
-* [[307-1015-00]] input voltage divider