Instrumentation & Test

This category mixes panel-mounted instruments with hand-held measuring tools, so the first question is which kind you are replacing.

Panel meters and counters

Match the panel cutout first. Common DIN cutouts are 45 x 45 mm (1/16 DIN), 45 x 92 mm (1/8 DIN) and 92 x 92 mm (1/4 DIN), and a meter that is a few millimetres off will not seat in the panel. Then match the input (4-20 mA, voltage, thermocouple, RTD or AC current), the supply voltage and the outputs. For counters and rate meters add the input type, such as a pulse or quadrature signal, and the maximum input frequency.

Process and temperature controllers

Identify the input first: thermocouple type (J, K, T and others), RTD, or a linear signal such as 4-20 mA. Then the control outputs (relay, solid state relay drive or analog), the number of alarms and the DIN size. A controller set to the wrong input type will read wrongly without giving an obvious error, so confirm the sensor before you order.

Signal conditioners and measuring tools

Signal conditioners and isolators convert or isolate signals such as 4-20 mA, 0-10 V, thermocouple and RTD, so match the input range, the output range, the isolation and whether the loop powers the device or a separate supply does. For hand-held instruments such as micrometers, calipers and gauges, note the measuring range, the resolution (for example 0.01 mm or 0.0005 in) and whether the scale is metric or inch.

What to have ready

• The model number as printed on the instrument
• Input signal or sensor type, and its range
• Panel cutout or DIN size
• Supply voltage
• Outputs, alarms or communication options fitted

Related guides and tools

• Tool: 4-20 mA Calculator
• Tool: Thermocouple / RTD Selector
• Tool: Obsolete Part Lookup

Not sure which one you have? Send us the number, a nameplate photo or the dimensions and the order desk replies within 1 business day.