ENGINEERING / DOCUMENTED SELECTION
6-Pin / 8-Pin Melt Pressure Wiring & R-Cal Guide
Compare model-specific bridge contact functions, understand shunt signals and request the correct wiring revision before energizing a replacement.
PT460-series and PT420-series bridge references
The comparison below follows Dynisco manual 974000, revision 1117, page 3, for its documented bridge configurations. It is not a pinout for every RMP, Gefran, GP:50, current-loop or voltage-output model.
| Contact letter | PT460-series 6-pin bridge | PT420-series 8-pin bridge |
|---|---|---|
| A | Signal + / red | Excitation + / white |
| B | Signal − / black | Signal + / red |
| C | Excitation + / white | Excitation − / green |
| D | Excitation − / green | Signal − / black |
| E | R-Cal / blue | R-Cal / blue |
| F | R-Cal / orange | R-Cal / orange |
| G / H | No such contacts in 6-pin shell | Unconnected in this bridge reference |
Color names describe the cable in the cited reference; do not identify an unknown cable by color alone. Front and solder-side views are mirrored: use the keyed connector drawing for the exact part. Official bridge manual, page 3.
Adapters need both electrical maps
Document the old and new mating connector part numbers, keyway, viewing direction, contact functions and shield path. The manufacturer lists separate 800860 / 800861 conversion assemblies; their existence does not make an arbitrary 6-to-8 harness compatible. Manufacturer connector and adapter reference.
Check ideal 80% signal values
Ideal scaling only; use the exact model manual to confirm excitation, R-Cal enable procedure, polarity and acceptance limits. No automatic wiring or calibration instruction is generated.
A shunt simulates bridge imbalance
For an ideal symmetric bridge, output ratio r = Rbridge / (4 Rcal + 2 Rbridge). A 350 Ω bridge at 80% of 3.33 mV/V gives r = 0.002664 and an illustrative Rcal ≈ 32.67 kΩ. Actual internal circuits and factory trim differ; this is not a resistor retrofit instruction.
Shielding follows the complete installation
Confirm the manufacturer's grounding and EMC instructions, cable construction and cabinet bonding. The cited Dynisco bridge manual describes a cable shield connected at the transducer end. That arrangement must not be generalized to every digital or safety-rated installation.