The methods below apply to all licensed French Bernard products; model designations (including internal part numbers) may differ — verify before use.
Bottom line: commissioning the Bernard GAMX-D positioner in five steps — (1) confirm rotation direction (press the limit switch; if ineffective, cut power immediately and swap two phases); (2) dead band via P3 (counter-clockwise reduces it); (3) cams 3 and 4 set the end positions; (4) P1 sets 0% and P2 sets 100%; (5) verify overload protection by pressing the torque switch manually. Then switch to AUT: 4 mA → 0%, 20 mA → 100%, proportional in between.
1. Installation
1.1 General — The SD series quarter-turn actuators are very flexible in model, overall and mounting dimensions; consult the manufacturer for special requirements.
1.2 Wiring — Internal wiring is factory-completed; the user connects only the external cables. Disconnect the supply before wiring.
2. Commissioning — Integrated modulating actuators are fully adjusted at the factory and normally need no readjustment. If special requirements call for it, proceed as follows:
2.1 Determining the direction of rotation — Turn the handwheel to mid-travel, set the AUTO/MAN switch to MAN, and pre-set the local manual control potentiometer P1 to mid-position (see Fig. 3, GAMX-D board layout). After power-up the actuator runs to the position preset on P1 and then turns in one direction. Press the limit switch of that direction with a screwdriver — rotation must stop. If it does not, cut the power immediately, swap two supply phases and try again. Once working, the actuator stops at mid-position; turning P1 then moves the actuator under control between 0° and 90°.
2.2 Dead-band adjustment — Adjust P3 (multi-turn potentiometer): turning P3 anticlockwise reduces the dead band.
2.3 Travel (end-position) adjustment — Disconnect power and open the travel-control box to expose the potentiometer cam mechanism.
For type B: remove the potentiometer bracket (8); below it is the cam disc holding four differently coloured and numbered cam plates — plates 4 and 3 (blue and black) control the start and end positions. To set the closed position, align a screwdriver with the slot of adjusting screw No. 4 on the cam plate, push down and rotate the cam towards close until the cam lobe just actuates the close limit switch. Adjust cam No. 3 the same way so it just actuates the open limit switch. Then tighten the three screws of the potentiometer bracket.
Note: on type A, cams 3 and 4 are the reverse of type B.
2.3.1 Zero adjustment (0%) — Set AUTO/MAN to MAN and power up. Turn P1 to the 0% end so the actuator runs towards CLOSE. If the actuator stops before reaching the close limit switch: loosen the three screws marked 9, rotate the potentiometer slowly (see Fig. 4) — the actuator follows until the driven cam stops just before the close limit switch and the LED just goes out — then re-tighten the three screws.
If the actuator keeps turning towards close past the close position (even though the close limit switch stops the actuator, the red LED stays lit): turn the potentiometer slowly in the other direction until the LED just goes out, then re-tighten the screws.
2.3.2 Span adjustment (100%) — Turn P1 (Fig. 3) to the 100% end; the actuator runs towards OPEN. If it stops before reaching the open limit switch (LED already out), turn span potentiometer P2 clockwise until the actuator stops just before the open limit switch. If it does not stop at the open position, turn P2 anticlockwise until the green LED goes out.
When the above is complete, set AUTO/MAN to AUT: with 4 mA the actuator goes to 0%; with 20 mA to 100%; between 4 and 20 mA it follows proportionally. Precise full-open/full-close positions can only be defined in automatic mode.
2.4 Checking the torque protection — While the actuator runs open or close, press the corresponding torque limit switch manually: the red LED flashes, the overload protection must stop the actuator. The protection unlocks automatically on reverse rotation or power-off.
3.1 — The GAMX-D electronic positioner accepts analogue or pulsed switch signals and outputs a position signal itself. Keep these signal cables at least 1 inch away from other cables, otherwise interference affects operation. The screen may be terminated at terminal "71" or the signal earth, which must be separate from the equipment earth.
3.2 — The GAMX-D input and output circuits are not isolated. If isolation is required, state this when ordering and add the isolation module.
3.3 — Before live commissioning on site, first confirm the actuator is correctly mounted on the valve.
3.4 — Before commissioning, carefully check the phase sequence of the three-phase supply and motor connections.
3.5 — Too small a dead band causes hunting; at minimum dead band the actuator only runs one way; too large a dead band gives no output in either direction.
3.6 — After commissioning, seal the cable entries and tighten the cover screws to prevent water ingress.
Quick reference — commissioning steps and precautions:
| Step | Action | Verdict / handling |
|---|---|---|
| 2.1 Rotation direction | Handwheel to mid-travel, selector to MAN, P1 pre-set mid-scale; power up and press the limit switch of the turning direction with a screwdriver | Rotation must stop; if not, cut power immediately, swap two phases and retry; when effective the actuator stops mid-travel and turning P1 moves it across 0°–90° |
| 2.2 Dead band | Adjust P3 (multi-turn pot) | Counter-clockwise reduces the dead band |
| 2.3 End positions (cams) | Power off, open the travel-control box; B type: screwdriver into cam slot 4, push down and turn the cam toward close until it just presses the close limit switch; likewise cam 3 for open; tighten the three potentiometer-bracket screws | Four colored cams; 4 and 3 (blue, black) are the end-position pair. Note: type A cams 3 and 4 are the reverse of type B |
| 2.3.1 Zero (0%) | Selector MAN, power on, P1 to the 0% end — actuator runs toward close | If it stops before the close limit switch: loosen screws 9, rotate the potentiometer slowly until the cam reaches the close limit and the LED just goes dark, then retighten |
| 2.3.2 Span (100%) | P1 to the 100% end — actuator runs toward open | Stops early with LED dark: turn P2 clockwise until it stops just before the open switch; still running at the open position: turn P2 counter-clockwise until the green LED goes out |
| 2.4 Overload check | During open/close running, press the torque switch manually | Red LED flashes, protection acts, actuator stops; protection auto-resets on reverse running or power-off |
| Acceptance | Selector to AUT | 4 mA → 0%, 20 mA → 100%, proportional across 4–20 mA; precise end positions are only settable in AUT |
| Item | Precaution |
|---|---|
| 3.1 | GAMX-D accepts analog or pulse signals and outputs position indication; signal cables must be separated from other cables (min. 1 inch); shield to terminal 71 or signal ground, which must be separate from equipment earth |
| 3.2 | GAMX-D input/output circuits are not isolated — order an isolation module if required |
| 3.3 | Before power-up commissioning, confirm correct mounting of actuator and valve |
| 3.4 | Check three-phase supply and motor phase sequence before commissioning |
| 3.5 | Too small a dead band causes hunting; extremely small — one-direction-only motion; too large — no output either way |
| 3.6 | After commissioning, seal the cable entries and tighten cover screws against water ingress |
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