Description
Product Core Brief
- Model: 1C31150G01
- Brand: Westinghouse / Emerson Ovation lineage, Ovation being the non safety related platform used for plant control while Common Q covers the 1E safety level
- Correct Class: Characteristic module, also called PMOD or personality module, for the pulse count path
- Core Function: Accepts 24/48V counting and control inputs from dry contacts or from open collector transistor drivers, with the input signal active low and referenced to the internal auxiliary supply return, the common negative branch
- Paired EMOD: 1C31147G01, the pulse accumulator covering 24/48V on CT plus and CT minus, 12V medium speed and 5V medium speed
- Not A Standalone Card: It runs no logic, has no firmware to program and no protocol stack
- Condition: New Original / New Surplus / Refurbished, demand nameplate photos
Product Introduction
1C31150G01 is the pulse count characteristic module that sits under the pulse accumulator EMOD. The EMOD does the counting, the PMOD decides what the field side looks like and how the input is referenced. This one takes 24/48V counting and control inputs from dry contacts or open collector transistor drivers, active low, referenced to the internal auxiliary supply common negative branch
That reference detail is the whole reason this part gets ordered wrong. If your circuit is wired active high and referenced to the internal auxiliary positive, you need 1C31150G02 instead, which accepts 24/48V dry contact counting and control inputs active high referenced to the internal auxiliary positive branch. If your counter needs its own field power, you need 1C31150G03, which provides a dedicated 24/48V counting and control field input supply taken from an external DC source connected to two base terminal block terminals, DSA and DSB
Ignore the trading page hype. Some sellers describe this as a plug in I/O module that runs on the Ovation backplane with redundant architecture and easy hot swap, while others paste whole variable frequency drive selection guides under the part number, talking about motor current, harmonic content, power factor and derating at altitude. Neither describes a passive characteristic module. A few pages even list it as a Rosemount transmitter that converts thermocouple or load cell signals into 4 to 20mA, which is completely unrelated
Key Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 1C31150G01 |
| Platform | Ovation DCS, Westinghouse and Emerson heritage |
| Module Class | Characteristic module, PMOD, for pulse counting |
| Input Type | 24/48V counting and control from dry contacts or open collector transistor drivers |
| Signal Polarity | Active low, referenced to internal auxiliary supply return, common negative |
| Paired EMOD | 1C31147G01, pulse accumulator for 24/48V, 12V medium speed and 5V medium speed |
| Sibling PMODs | 1C31150G02 active high dry contact referenced to internal auxiliary positive, 1C31150G03 dedicated external 24/48V field supply via DSA and DSB |
| Mounting | Ovation standard and compact modules install in base units on DIN rails, and each base holds two I/O modules with two terminal blocks even if only one module is used |
| Jumpers | Most Ovation personality modules have no configurable jumpers, and where they exist the card must come out of the PMOD case to change defaults |
| Typical Failure Mode | Cracked case, corroded terminal, burned trace, missed counts from wrong polarity PMOD, intermittent count from loose clamp |
| Handling | Anti-static bag with desiccant, store flat, keep away from conductive dust |
| Verification Method | Confirm active low or active high and internal or external field supply against cabinet drawing and Ovation hardware manual |
Quality Control Process
A pulse PMOD gets continuity, polarity and pulse injection checks, not a firmware load.
- Nameplate and suffix match. Confirm G01, not G02 or G03. All three sit on the same shelf and cover different wiring schemes.
- Polarity confirmation. Verify your field circuit is active low referenced to common negative before accepting G01.
- EMOD pairing check. Confirm the pulse accumulator is 1C31147G01 and that your pulse voltage class matches one of its three input levels
- Continuity trace with a Fluke multimeter. Probe from the field terminal through to the mating point on every channel.
- Pulse generator injection. Feed a known count and compare the accumulated value against the generator at your real field rate.
- Contact bounce observation. Watch for double counting with a bouncing dry contact, which inflates totals silently.
- Clamp and thread check. Run every screw in by hand first. Cross threaded clamps walk loose under vibration weeks later.
- Insulation test using a Megger. Confirm no short between input groups and cabinet ground.
I once saw a plant lose roughly four percent on fuel totalizing for months. The EMOD was healthy. Someone had installed the active high PMOD on a circuit wired for active low, so half the pulses never registered and nothing alarmed.
Replacement Pitfall Guide
Buying G02 for an active low circuit. G02 accepts dry contact inputs active high referenced to the internal auxiliary positive, so swapping it silently drops pulses instead of fixing them
Buying G03 thinking it is a generic upgrade. G03 only provides a dedicated 24/48V field input supply from an external DC source connected to the DSA and DSB base terminals, so it changes your power scheme entirely
Believing it counts at 100 MHz. Some pages claim the pulse path supports speeds up to 100 MHz with single ended, differential and quadrature inputs plus software configurable filtering and non volatile count storage. That is copied generic counter marketing and does not match Ovation pulse accumulator documentation
Expecting hot swap convenience in every cabinet. Sellers describe fast low risk swaps on the backplane with redundant architecture, but you still need to put points out of service and stop scanning before pulling hardware in most Ovation setups
Ignoring the base unit. Ovation modules mount in base units on DIN rails and each base contains two terminal blocks even when only one I/O module is used, so a cracked base makes a good PMOD look dead
Assuming jumpers can be changed in place. Where a personality module has configurable jumpers, the card usually has to come out of the PMOD case to change default settings
Trusting random pricing. One older Ovation price sheet listed the 24/48V pulse input card 1C31147G01 at 32000 and 1C31150G01 at 5500, while trading listings show anywhere from a single dollar placeholder to negotiated quotes with two to three day lead times. Treat all of it as unverified
Keep these in mind and you’ll cut most rework time.
Compatibility Matrix & Benchmarks
| Original Model | Replacement / Alternative | Compatibility Level | Migration Notes |
|---|---|---|---|
| 1C31150G01 | Refurbished same part | Direct | Inspect terminals, run continuity, insulation and pulse injection |
| 1C31150G01 | 1C31150G02 | Needs Adaptation | Active high dry contact referenced to internal auxiliary positive, rewiring required |
| 1C31150G01 | 1C31150G03 | Needs Adaptation | Needs external DC field supply wired to DSA and DSB base terminals |
| 1C31150G01 | 1C31147G01 | Not Compatible | Pulse accumulator EMOD, pairs rather than replaces |
| 1C31150G01 | 1C31147G02 | Not Compatible | 5V high speed pulse EMOD, different signal class |
| 1C31150G01 | Third party pulse counter interface | Needs Adaptation | Loses native Ovation registration and diagnostics, needs isolation and supply redesign |
Benchmark references
- Acceptance criterion: accumulated count matches the pulse generator exactly over at least 1000 pulses at your real field rate.
- Polarity target: every simulated contact closure registers once, with no double counting from bounce.
- Drift target: daily totalized value stays within plant tolerance against a reference meter over a week.
Procurement Notes
Push for four things before paying: a clear nameplate photo showing the G01 suffix, confirmation from the seller that it is a pulse count characteristic module for active low 24/48V inputs rather than a controller, transmitter or VFD, confirmation of which pulse accumulator EMOD and base it pairs with, and customs paperwork if it is claimed as imported original stock.
If a seller describes it as a Rosemount transmitter, a variable frequency drive needing derating at altitude, or a high speed counter running to 100 MHz with quadrature inputs, treat the listing as unverified and move on. That usually means nobody in that office has opened an Ovation cabinet.
