Logic that matches the specification, line for line
Many safety system defects start in the specification and the application logic rather than the hardware. These packages check application logic against the cause & effect and SRS, and deliver control logic that can be tested and maintained.
Service packages
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SIS & ESD Logic Review
Every trip, bypass, reset and voting path in the safety application checked against the cause & effect matrix and the SRS. Findings are classified by consequence, so the critical ones are fixed first.
Deliverables
- Logic review report
- Deviation list with severity
- Suggested corrections
from $240 per functionMinimum $2,400; large systems priced by I/O count
See an example deliverable
ID Finding Reference Severity F-01 Trip reset possible from the operator station without a local confirmation SRS reset requirement High F-02 Maintenance override of PT-12B has no time limit SRS bypass requirement High F-03 On one bad PV the voting degrades to 1oo2 instead of 2oo2 Cause & effect rev B Medium F-04 XV-12 limit switch discrepancy alarm not passed to the DCS Alarm philosophy Low Illustrative excerpt written for this site; tags and values are invented, not client data. -
DCS & PLC Application Engineering
Control strategies, interlocks and sequences written from a control narrative, with operator graphics built to ISA-101 high-performance HMI principles and test records for each one.
Deliverables
- Control narratives
- Application logic
- ISA-101 style operator graphics
- Internal test records
from $350 per control moduleInterlocks and sequences quoted after the narrative review; $850 per day for larger scopes
See an example deliverable
Test Expected Result Manual to auto transfer Bumpless; output holds at the last value Pass PV quality bad Loop goes to manual, output held, alarm raised Pass Interlock from LSLL-202 FV-201 closes and stays closed until reset Pass Setpoint limits Operator entry clamped to 0–120 m³/h Pass Faceplate Tag, units and alarm colours as per the HMI style guide Pass Illustrative excerpt written for this site; tags and values are invented, not client data. -
Machinery Protection Review
Configuration of a vibration and position monitoring system reviewed against machine data, the protection philosophy and API 670, with a maintenance and test plan.
Deliverables
- Configuration review
- Alarm and trip setpoint register
- Maintenance and test plan
from $1,300 per machine trainConfiguration review, setpoint register and test plan
See an example deliverable
Measurement Alert / danger Voting and delay Finding Radial vibration, drive end X/Y 75 / 112 µm pk-pk 2oo2, 1 s Consistent with OEM limits Axial position ± 0.5 / ± 0.7 mm 2oo2, 1 s Re-zero after the thrust bearing change is not recorded Overspeed 105 / 110 % 2oo3 Consistent; trip test due Bearing temperature 105 / 115 °C 1oo1 trip Single sensor trips the train: consider 2oo2 with deviation alarm Illustrative excerpt written for this site; tags and values are invented, not client data.
Systems worked on
Hands-on configuration, programming and maintenance experience. Product names describe experience only; this work is independent of the manufacturers.
Safety systems
- Triconex safety instrumented systems
- Honeywell Safety Manager SC
- HIMA safety PLCs
Process control
- Foxboro DCS
- SIMATIC PCS 7
- SIMATIC S7-1500 with TIA Portal
- SIMATIC S7-300
- ISA-101 high-performance HMI
Machinery protection
- Bently Nevada 3500 machinery protection system
- API 670 practice for vibration and position monitoring
How a logic review runs
The review works from exported application files or printouts, the cause & effect matrix and the SRS. Each safety function is traced from input to output and compared with what the specification says it should do, including voting, time delays, bypass permissives and reset behaviour.
No connection to a live control or safety network is needed or requested.
Questions
Do you need access to our live system?
No. Reviews use exported application files, printouts or screenshots that you provide. Live systems are never accessed remotely.
Can you work on systems not listed here?
The review method applies to any safety PLC. For platforms outside the list, the proposal states it plainly and the time estimate reflects it.
Do you work for system manufacturers or integrators?
Enquiries from manufacturers and integrators are screened for conflicts of interest first and may be declined.