MNM MS-202 NTEP Scale Indicator Guide: Wiring, RS-232, Calibration & Specs
- pete8781
- Jul 29
- 3 min read
For product details, replacement-indicator help or compatibility questions, call MNM Scales at (832) 290-3120 or email mnmscales@yahoo.com.
The MNM MS-202 NTEP scale indicator is a Legal-for-Trade digital readout sold by MNM Scales for floor scales, hoppers, small truck-scale systems and other strain-gauge load-cell applications that need a straightforward LCD indicator with serial output. MNM identifies the unit with the PS-IN202 family and lists NTEP Certificate of Conformance 12-112, making model identification, correct wiring and correct calibration especially important when replacing an older indicator in a commercial weighing system.
MS-202 Key Specifications and Functions
MNM lists a 0.7-inch high-contrast LCD, configurable analog-to-digital measurement rate, gross/net display, motion detection, automatic zero maintenance, counting, printer/continuous output and slave mode for use as a remote display. The indicator can power as many as eight 350-ohm load cells, which is useful for multi-cell floor and platform systems. Power is supplied by the included 110V AC/DC adapter or the internal rechargeable battery, so the readout can remain useful during mobile service work or short periods away from line power.
MNM lists overall dimensions of approximately 9.3 inches long by 2.8 inches deep by 6.5 inches high with the bracket. The mounting bracket allows wall or tilt-stand installation. The front controls provide the functions operators use most often—unit selection, zero, net/gross, tare and print—without requiring a complicated touchscreen interface.
Load-Cell and RS-232 Connectivity
The PS-IN202 documentation identifies the common four-wire load-cell colors as red for +Excitation, black for -Excitation, green for +Signal and white for -Signal. Before moving wires from an old indicator, confirm the actual cable and connector pinout rather than assuming wire color alone proves compatibility. The indicator also provides full-duplex RS-232 connectivity for compatible printers or computers, which makes the MS-202 useful where weight tickets, serial data capture or external displays are part of the workflow.
Where the MS-202 Fits Best
Common targets include four-cell floor scales, pallet platforms, livestock platforms, suspended hoppers, ingredient or batching systems, compact vehicle or axle systems and replacement jobs where an older NTEP indicator has failed. For exact wiring and installation work, see the dedicated MS-202 wiring guide. For service calibration, use the dedicated P11/P12 calibration article. For buyers replacing an old readout, the replacement guide explains what must match besides the connector shape.
Calibration and Setup Overview
The PS-IN202 manual places configuration in a setup “P” menu and calibration in P11 and P12. P11 establishes the unloaded zero/dead-load reference. P12 establishes span with known test weight. Capacity, units, divisions, decimal position, filtering and other setup values must be appropriate for the connected weighing system before calibration data can be meaningful. A good service workflow checks the platform mechanically first, confirms stable load-cell signal and wiring, then performs zero and span, followed by several verification loads across the working range.
Troubleshooting Before Replacing the Indicator
An unstable or incorrect weight does not automatically mean the indicator is bad. Inspect the platform for binding, check junction-box moisture, verify excitation and signal wiring, inspect the load-cell cable for cuts, and test whether the reading changes smoothly when load is applied. A display that powers normally but shows erratic weight may be receiving a bad signal from the platform; a system that returns to zero poorly may have mechanical binding or a damaged load cell. Separating indicator faults from sensor faults can prevent buying the wrong replacement component.
Frequently Asked Questions
Is the MNM MS-202 Legal for Trade?
MNM lists the MS-202 / PS-IN202 as NTEP approved with COC 12-112. A complete commercial installation still has to use an appropriate approved scale configuration and satisfy local weights-and-measures requirements.
How many load cells can it power?
MNM states that the indicator can power up to eight 350-ohm load cells, which covers many common floor-scale and multi-cell platform designs.
Can the MS-202 connect to a printer or computer?
Yes. The listing and PS-IN202 documentation identify serial output and full-duplex RS-232 connectivity for compatible printers or computers.
Does it support counting?
Yes. Counting is one of the functions listed for the indicator, making it useful beyond simple gross-weight display when the connected scale has suitable resolution for the parts being counted.
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