Pressure Measurement · Pressure Transmitters
Diffusion silicon pressure transmitters built in a family of housings, from a plain plug version to sanitary, high-temperature, explosion-proof and 4G wireless forms, with 4-20 mA, voltage or RS-485 Modbus output.
MIK-P300 ·
A pressure transmitter turns the pressure at a tapping point into a signal a control system can read. The instrument on this page uses a diffusion silicon sensing element and covers gauge, absolute and sealed gauge references, with a span from -100 kPa up to 60 MPa across the series. Output is 4-20 mA two-wire as standard, with 0-5 V, 1-5 V, 0-10 V and RS-485 Modbus available by configuration.
What distinguishes this series is not the element but the number of constructions built around it. The same measurement module is offered in a plain plug housing, a short housing for a tight installation, a finned housing for hot media, a housing with a four-digit display, a GX12 circular connector version, a flush-diaphragm sanitary version with a clamp connection, a die-cast aluminium housing, a flanged version, and forms with a 4G radio or a flameproof enclosure. That range exists because the element is small and the electronics are a circuit board; once those two are fixed, the housing is what decides where the instrument can be used.
The measuring element itself is a silicon diaphragm with a diffused resistor network, isolated from the process by a thin diaphragm and a fill fluid in industrial constructions. The medium therefore meets the wetted metal rather than the silicon, and the element stays at a temperature the compensation can handle. Everything the housing does follows from protecting that arrangement without distorting what it reads.
A finned housing moves heat away from the electronics, which is why a high-temperature construction exists at all: the limit is usually the circuit and the fill fluid rather than the diaphragm, and the fins buy back the difference. A flush diaphragm removes the dead volume in front of the element, so a medium that would stagnate or hold residue in a threaded port does not have anywhere to sit. A flameproof enclosure contains an internal fault rather than preventing it, which is why it changes what the instrument is permitted to be installed next to, and nothing about what it measures. A radio version removes the cable, which changes the installation cost far more than it changes the measurement.
Two figures move with the span rather than with the housing, and they are worth reading together. Temperature drift within the compensated range is 2%FS on spans from 10 to 60 kPa and 1.5%FS above that, and the compensated range itself is 0 to 60°C, 0 to 70°C or -10 to 70°C depending on the span band. A narrow span on a cold outdoor installation is therefore a different proposition from the same instrument indoors.
Settle the pressure type first. A gauge transmitter reads against local atmosphere and suits a pump discharge, a compressed air line or a vented tank. An absolute transmitter reads against a sealed vacuum and is the right choice where the barometric term must not appear in the reading. A sealed gauge transmitter holds a fixed internal reference and is used where a vented reference would fill with the medium. A compound range crossing zero is a fourth case again, and it is not interchangeable with a sealed gauge instrument of the same numeric span.
Then settle the span against the working pressure rather than the peak. The accuracy grade applies to the full scale of the span selected, so a range several times the normal working pressure spends its life reading a small fraction of full scale and reports less than it could. The published overpressure figure - 150%FS up to 10 MPa and 125%FS above it - covers short spikes such as a pump start or a line test, not a sustained overrange.
Then settle the environment, because that is what selects the housing: media temperature picks between the standard and finned constructions, the cleanliness requirement picks the flush diaphragm, the area classification picks the enclosure, and the distance to the control system picks between a loop and a radio. Media compatibility is the remaining item, and the supplied material does not state the diaphragm or port material, so an aggressive medium has to be raised with the enquiry rather than assumed.
The supply range and the loop resistance are published together because one constrains the other. On the current output, the load a two-wire loop can drive is RL ≤ (U-10 V)/0.02 A without a local display and RL ≤ (U-14 V)/0.02 A with one, where U is the supply voltage. The difference between the two expressions is the voltage the display needs, and using the wrong one is how a loop that looked comfortable on paper reads low at the top of its range. On the voltage outputs the constraint is a minimum load of 5 kΩ rather than a maximum.
The supply itself changes with the output and the display: 10-32 V for 4-20 mA, 8-32 V for 0-5 V or 1-5 V, 12-32 V for 0-10 V, and on RS-485 either 8-32 V, 7-32 V or 5-28 V depending on whether a display is fitted and whether it is LCD or LED. The pin functions are not the same across the output forms, so the wiring is read from the form ordered rather than from the series in general.
A transmitter selected with far more span than the duty needs is the most common way to make a good instrument read poorly. The grade applies to full scale, so the error at the working point grows in proportion to how much of the span is unused.
Narrow spans on cold installations deserve a second look, because the compensated range narrows as the span narrows and the drift figure rises. Where the process sits at the bottom of a narrow span outdoors, a different sensing technology or a wider span may serve better than a tighter grade on the same instrument.
A transmitter is also the wrong instrument where the question is not continuous. If the requirement is a contact that changes state at a set point, a pressure switch does that without a loop; if the requirement is a local indication and nothing else, a gauge does it without a supply. Where the medium is aggressive, the answer is usually a separating diaphragm ahead of the instrument rather than a more exotic wetted metal, and where the medium pulses hard, the damping structure in the port helps but does not replace a proper snubber.
The supplied material does not give a model code breakdown for the series, so a configuration is stated in words: pressure type, range, output form, supply, process connection, electrical connection, housing and lead length. That is also what a quotation needs, and it is the order in which the choices constrain each other - the output form fixes the supply range, the supply range fixes the load that can be driven, and the housing fixes the media temperature that applies.
Every value below is taken from source documentation. Where a parameter is not stated in the available material it is marked as information required rather than estimated.
| Measured variables | Gauge, absolute and sealed gaugeStandard |
|---|---|
| Range span | -100 kPa to 60 MPa over the seriesStandard |
| Accuracy grades | 0.2, 0.25 and 0.5 grade; the promoted comparison figure on the listing is not a grade — see the note belowInformation required |
| Long-term stability | ±0.2%FS per yearStandard |
| Temperature drift within the compensated range | 2%FS on spans from 10 to 60 kPa; 1.5%FS on spans above 60 kPa up to 60 MPaStandard |
| Compensated temperature range | 0 to 60°C from 10 to 25 kPa; 0 to 70°C from 25 to 60 kPa; -10 to 70°C above 60 kPaStandard |
| Response time | T90 ≤ 10 ms on current and voltage output; T90 ≤ 100 ms on RS-485Standard |
| Reference standard behind the accuracy figure | Information requiredInformation required |
| 4-20 mA | Two-wire; pin 1 to supply positive, pin 2 to the receiving instrumentStandard |
|---|---|
| 0-5 V, 1-5 V, 0-10 V | Three-wire; pin 1 to supply positive, pin 2 common, pin 3 signalOptional |
| RS-485 | Modbus protocol, two-wire; the terminal definition is not given in the supplied materialInformation required |
| Supply voltage | 10-32 V on 4-20 mA; 8-32 V on 0-5 V or 1-5 V; 12-32 V on 0-10 V; 8-32 V on RS-485 without display, 7-32 V with a 4-digit LCD and 5-28 V with a 4-digit LED displayStandard |
| Load resistance | RL ≤ (U-10 V)/0.02 A without a display; RL ≤ (U-14 V)/0.02 A with a display; ≥ 5 kΩ on the voltage formsStandard |
| Power consumption at 24 VDC | ≤ 0.6 W current output; ≤ 0.05 W voltage output; ≤ 0.2 W RS-485Standard |
| Insulation | 20 MΩ at 250 VDC; 500 VAC at 50 HzStandard |
| Electrical connection | Flying leads, GX12 circular connector or DIN43650-A plug, by configurationStandard |
| Standard lead length | 2 mStandard |
| Media temperature | -20 to 85°C on the standard constructionStandard |
|---|---|
| Media temperature, high-temperature construction | Stated as 300°C for that housing, which is a housing marking rather than the series figure — confirm the media temperature for the actual dutyInformation required |
| Operating temperature | -20 to 85°CStandard |
| Storage temperature | -40 to 85°CStandard |
| Sealing | IP65Standard |
| Overpressure | 150%FS from 0.035 to 10 MPa; 125%FS from 10 to 60 MPaStandard |
| Wetted material | Not stated beyond the 3 mm pressure port and the O-ring sealing of the housingInformation required |
| Medium compatibility | Stated for general liquid, gas and steam duties; a medium that attacks the wetted parts is not covered by the general statementStandard |
| Standard thread | M20×1.5Standard |
|---|---|
| Further threads | M14×1.5, G1/4 and G1/2 from the sales sheet; others to orderStandard |
| Flange and clamp versions | Single and double flange, and a flush diaphragm with a clamp connection on the sanitary housingOptional |
| Thread length and port diameter | Marked L and D on the outline drawings without a value table; the figures move with the thread orderedInformation required |
| Body diameter | Φ26.5 mm on the standard housing; Φ26.5 mm with a Φ10.7 mm bore on the high-temperature housingStandard |
|---|---|
| Across flats | 27 mmStandard |
| Thread length | 12 mm on the standard housingStandard |
| Overall height, standard housing | 81.5 mm plug form without display; 96.5 mm plug form with RS-485; 94 mm display form without RS-485; 121 mm display form with RS-485Standard |
| Overall height, high-temperature housing | 120.5 mm, 135.5 mm, 146 mm or 161 mm across the four formsStandard |
| Scope | Additional forms supplied in November 2026 for this product type. Figures below are from that batch; where they differ from the rows above, both are recorded rather than merged.Standard |
|---|---|
| Ranges in this batch | 0-0.6 MPa, 0-1 MPa and 0-1.6 MPa as the common spansStandard |
| Accuracy | 0.2 class and 0.5 class, with plus or minus 0.15 % and 0.03 % figures on some listingsStandard |
| Output | 4-20 mA, RS-485/Modbus, HART and 0-10 VStandard |
| Supply | 24 V DC as standard, with 12 V DC and battery-powered versionsStandard |
| Process connection | M20 x 1.5, G1/2 and NPT1/2Standard |
| Wetted material | 316L stainless, 304 stainless and PTFE diaphragmStandard |
| Medium temperature | 10 to 70 C on the general form, with high-temperature versions to 350 CStandard |
| Ingress protection | IP65, with IP67 versionsStandard |
| Model | Configuration | Key ranges | Availability |
|---|---|---|---|
| Standard housing | DIN43650-A plug, no display | 4-20 mA, 24 VDC, M20×1.5 | Ambient-temperature liquid, gas or oil on general plant duties |
| Compact housing | Short body | As configured | Where the installation depth at the tapping point is limited |
| High-temperature housing | Five radiator fins, stated for media to 300°C | As configured | Hot media; confirm the media temperature for the duty against the housing marking |
| Digital display housing | 4-digit LCD or 4-digit 8-segment LED | 4-20 mA or RS-485 | Where a local reading is wanted at the tapping point |
| Circular connector housing | GX12 connector | As configured | Machinery where the cable is supplied and fitted separately |
| Sanitary housing | Flush diaphragm with a clamp connection | As configured | Pharmaceutical, medical and brewing duties |
| 2088 housing | Die-cast aluminium | As configured | High-temperature water and oil duties |
| Single-crystal silicon housing | Single-crystal silicon element in place of the diffusion silicon chip | As configured | A different sensing element from the rest of the series |
| Flanged housing | Single or double flange | As configured | Flange mounting at the tapping point |
| Wireless housing | 4G remote transmission | As configured | Several pressure points read remotely |
| Explosion-proof housing | Flameproof enclosure | As configured | The supplied material gives no approval mark, certificate number or hazardous-area classification for this housing |
Certifications are only published once a certificate copy can be produced, so this section is deliberately empty rather than populated with assumed approvals. Tell us which approvals your application requires and we will confirm what is available for this instrument.
The following are required for a complete specification but are not stated in the documentation supplied to us. They are listed rather than estimated:
Start from the environment and the medium rather than from the electronics, because the housing is what decides where the instrument can physically be used and the electronics are available in most of them. If the medium is a pharmaceutical, medical or brewing product, the sanitary housing with a flush diaphragm and a clamp is the only one of the family that does not leave a crevice at the process face. If the medium is hot, the high-temperature housing with its fins is the construction intended for it, and the media temperature for that duty should be confirmed rather than read off the series table. If the tapping point is in a hazardous area, the flameproof housing is the one to ask about, and approval documentation has to be requested with the enquiry. Everything else is settled by what connector the cable and the installation call for.
Two-wire 4-20 mA is the default and suits most installations, because the same two conductors carry the supply and the signal and a small voltage drop along the cable does not change the reading. A three-wire voltage output suits a short run into a controller that takes a voltage input. RS-485 suits a transmitter that has to be read digitally alongside others on the same bus, and the Modbus protocol is stated for it. The pin functions differ between the three forms and the supply range differs as well, so the output is settled before the wiring is planned rather than afterwards.
Because the display and its driver draw from the same loop supply, so more voltage has to be available at the instrument before the output stage still has enough headroom. On RS-485 the published range is 8-32 V without a display, 7-32 V with a four-digit LCD and 5-28 V with a four-digit LED display. On the current output the supply range changes the load resistance that can be driven: RL ≤ (U-10 V)/0.02 A without a display and RL ≤ (U-14 V)/0.02 A with one. Checking the supply against the loop resistance before ordering is what avoids an instrument that reads correctly on the bench and not in the panel.
The pressure type - gauge, absolute or sealed gauge - and the range, since a compound range and a sealed gauge range of the same span are different instruments. Then the output form, the supply available at the point, the process connection thread and the electrical connection. If the medium is not a general liquid, gas or steam duty, say what it is. If the medium or the ambient is hotter than the standard figures, say so, because the high-temperature construction is a separate housing. For a hazardous area, state the classification required, because no approval for that housing is documented in the material supplied to us.
The parameter panel lists 0.2, 0.25 and 0.5 grade, and which of them applies depends on the range and the configuration ordered. A separate promotional panel on the same listing contrasts a 0.2% figure with a 0.5% figure and attributes them to different chips; that panel is a sales comparison rather than a grade list, and it is not used here. The grade that applies to a specific range is confirmed when the range is quoted.
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