Limit-Sensing Ohmmeter -
Model 5012-06XR

The Harris IRT Enterprises Limit-Sensing Ohmmeter - Model 5012-06XP is designed for portable production resistance testing in an industria environment. It is a high-resolution, digital ohmmeter that couples laboratory precision with the durability and reliability needed by industry. The use of a four terminal resistance measurement system eliminates the inaccuracies introduced by test lead resistance. When a large number of similar components are to be tested, high and low resistance limits are set using front panel thumbwheels. Indicator lamps light when a component’s resistance is above, below or within test limits. An output relay is triggered to permit the automated rejection of unacceptable components. The Model 5012-06XR makes 100% production testing practical, simple, and economical without giving up accuracy and resolution.

SPECIFICATIONS

OPERATING RANGES:

RANGE 0 - .2 ohms 0 - 2 ohms 0 - 20 ohms 0 - 200 ohms 0 - 2000 ohms 0 - 20000 ohms

RESOLUTION 0.0001 ohm 0.001 ohm 0.01 ohm 0.1 ohm 1.0 ohm 10.0 ohms

TEST CURRENT 100 milliamps 100 milliamps 10 milliamps 1 milliamp 100 microamps 100 microamps

Test voltage for 0 - 2000 ohm ranges: 200 millivolts Full Scale
Test voltage for 20000 ohm range: 2 volts Full Scale

ACCURACY:

±0.05%, ±1 digit at 25°C
±0.001% per °C, 0°C to 50°C

DISPLAY:

3½ digit, 0.5" [12.7mm] LED.

READING RATE:

5 per second.

AUTO ZEROING:

Between display readouts.

POWER REQUIREMENTS:

117VAC ±10%, 50-60Hz, 5 Watts (230VAC optional).

ENCLOSURE:

Rackmount anodized aluminum case 19" [483mm] wide by 14" [356mm] deep by 3.5" [89mm] tall.

Download Model 5012-06XR Specification Sheet

OPTIONS

Temperature Compensation

Temperature changes of a few degrees in a product can produce significant changes in the resistance of the product. Temperature compensation allows for varying product temperature by providing the Model 5012-06XR with the ambient temperature. The tester then compensates for differences between the ambient temperature and the standard measurement temperature. The accuracy of the temperature compensation is within 0.2% of the actual resistance between 0° and 50°C.

Download Temperature Compensation Option Specification Sheet

Diode Test Option

Many of our IRT customers have the requirement to verify the presence and proper polarity of the DC shunt diode installed on a solenoid to prevent high voltage transients during coil activation and de-activation. Because the maximum test voltage produced by the Model 5012-06XR is 0.200V, the shunt diode forward voltage drop is not exceeded and the diode does not conduct. This permits accurate measurement of the coil resistance up to 2000 Ohms, but does not make it possible for the resistance tester to detect the diode or its polarity.

Our newly introduced Diode Test Option effectively tests for the presence and the polarity of the shunt diode on a DC coil. The required test polarity (which terminal is the diode anode and which is the cathode) is selected by a jumper on the option board. This jumper can be front-panel mounted as necessary for production setup.

The Model 5012-06XR test circuit functions in the normal manner. When the resistance test is complete, an external contact closure from the test controller or PLC is used to initiate the diode polarity test. The polarity test automatically locks the Model 5012-06XR resistance reading and limit status so that it may be read while the diode test is in progress.

Computer Interface

The Model 5012-06XR is available with two types of computer interface, RS-232 and Binary Coded Decimal (BCD). The RS-232 interface is a three-wire link that is a standard, null-modem connection with a baud rate of 9600. Protocol 9600,N,8,1 with no handshaking needed. The RS-232 interface is useful for statistical analysis of production, predictive control and data logging. It is compatible with any computer having a RS-232 port and any terminal program.

The BCD output allows the resistance tester to transmit readings to a Programmable Logic Controller (PLC). The BCD option generates a 1, 2, 4 and 8 bit for each of the 5 digits in the resistance reading. An output strobe is also provided to allow synchronization of the resistance tester with the PLC. The BCD output is a TTL logic level of 0 to 5 VDC and a maximum output current of 24mA.

Freeze Option

A set of contact closures allow the operator to hold the current reading even after disconnecting from the part under test. The reading will continue to be held until the contact closure is released.

The Freeze Option is not compatible with the Diode Test Option.

Sample & Hold Option

A contact closure triggers the high speed sampling of the voltage drop measured across the unknown resistance. The voltage can be acquired in as little as 10 milliseconds while the test probes are in contact with the resistance to be measured. The test voltage is stored for processing with the system analog to digital converter. The 5012-06XR will display the measurement calculated from this stored voltage even though the part is no longer in contact with the test probes. The limit sensors and Go relay will operate normally. The display and limits will not update until another sample is triggered.

not compatible with the Diode Test Option.

Alarm Connections

Alarm connections are available as special terminal connections for activating audible or other alarms.

Safety Relays

When a resistance tester is used in a system in conjunction with high pot or surge tests, an internal safety relay can be provided to lock out the resistance tester circuitry during other testing. This will protect the test equipment from possible high voltage damage.

230VAC Service

The Model 5012-06XR is available with 230VAC 50Hz operation upon request at no extra charge.